MIC3001BML

MIC3001 FOM Management IC with Internal Calibration Consider MIC3003 for New Designs General Description Features The MIC3001 enables the implementation of sophisticated, hot-pluggable fiber optic transceivers with intelligent laser control and an internally calibrated digital diagnostic monitoring interface per SFF-8472. It essentially integrates all non-data path functions of an SFP transceiver into a tiny (4mm × 4mm) QFN package. A highly-configurable automatic power control (APC) circuit controls laser bias. Bias and modulation are temperature compensated using dual DACs, an on-chip temperature sensor, and NVRAM look-up tables. A programmable internal feedback resistor provides unprecedented dynamic range for APC. Controlled laser turn-on facilitates hot plugging. An analog-to-digital converter converts the measured temperature, voltage, bias current, transmit power, and received power from analog to digital. An EEPOT provides front-end adjustment of RX power. Each parameter is compared against user-programmed warning and alarm thresholds. Analog comparators and DACs provide highspeed monitoring of received power and critical laser operating parameters. Data can be reported as either internally calibrated or externally calibrated. An interrupt output, power-on hour meter, and data-ready bits add user friendliness beyond SFF-8472. The interrupt output and data-ready bits reduce overhead in the host system. The power-on hour meter logs operating hours using an internal real-time clock and stores the result in NVRAM. Communication with the MIC3001 is via an industry standard 2-wire serial interface. Nonvolatile memory is provided for serial ID, configuration, and separate OEM and user scratchpad spaces. Two-level password protection guards against data corruption. Data sheets and support documentation can be found on Micrel’s web site at: www.micrel.com. • APC or constant-current laser bias • Turbo mode for APC loop start-up and shorter laser turn on time • Supports multiple laser types and bias circuit topologies • Drives external low-cost BJT for laser bias • Integrated digital temperature sensor • Temperature compensation of modulation, bias, and fault levels via NVRAM look-up tables • Direct interface to SY88932, SY88982, SY89307 and other drivers • NVRAM to support GBIC/SFP serial ID function • User writable EEPROM scratchpad • Diagnostic monitoring interface per SFF-8472 − Monitors and reports critical parameters: temperature, bias current, TX and RX optical power, and supply voltage − S/W control and monitoring of TXFAULT, RXLOS, RATESELECT, and TXDISABLE − Internal or external calibration − EEPOT for adjusting RX power measurement • Power-on hour meter • Interrupt capability • Extensive test and calibration features • 2-wire, I2C-compatible serial interface • SFP MSA and SFF-8472 compliant • 3.0V to 3.6V power supply range • 5V-tolerant I/O • 4mm × 4mm 24-pin QFN package Applications • • • • • • SFF/SFP optical transceivers SONET/SDH transceivers and transponders Fibre channel transceivers 10Gbps transceivers Free space optical communications Proprietary optical links MLF and MicroLeadFrame are registered trademarks of Amkor Technology Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com August 2004 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Ordering Information Package Type Junction Temperature Range Package Marking Lead Finish MIC3001BML 24-Pin QFN −45°C to +105°C 3001 Sn-Pb or NiPdAu MIC3001BMLTR(1) 24-Pin QFN −45°C to +105°C 3001 Sn-Pb or NiPdAu MIC3001GML 24-Pin QFN −45°C to +105°C MIC3001GMLTR(1) 24-Pin QFN −45°C to +105°C 3001 with Pb-Free Bar-Line Indicator 3001 with Pb-Free Bar-Line Indicator Part Number NiPdAu NiPdAu Note: 1. Tape and Reel. August 2004 3 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Contents General Description ...................................................................................................................................................... 1 Applications ................................................................................................................................................................... 1 Ordering Information .................................................................................................................................................... 2 Pin Configuration .......................................................................................................................................................... 7 Pin Description .............................................................................................................................................................. 7 Absolute Maximum Ratings ......................................................................................................................................... 9 Operating Ratings ......................................................................................................................................................... 9 Electrical Characteristics ............................................................................................................................................. 9 Timing Diagram ........................................................................................................................................................... 14 Address Map ................................................................................................................................................................ 15 Block Diagram ............................................................................................................................................................. 17 MIC3000 Capability...................................................................................................................................................... 17 Analog-to-Digital Converter/Signal Monitoring.......................................................................................................... 17 Internal/External Calibration...................................................................................................................................... 19 A/ External Calibration .............................................................................................................................................. 19 Voltage.................................................................................................................................................................. 19 Temperature ......................................................................................................................................................... 19 Bias Current .......................................................................................................................................................... 19 TX Power .............................................................................................................................................................. 19 RX Power.............................................................................................................................................................. 20 B/ Internal Calibration ................................................................................................................................................. 20 C/ ADC Result Registers Reading ............................................................................................................................. 22 RXPOT ...................................................................................................................................................................... 22 Laser Diode Bias Control .......................................................................................................................................... 22 Laser Modulation Control .......................................................................................................................................... 23 Power ON and Laser Start-Up .................................................................................................................................. 24 Fault Comparators .................................................................................................................................................... 25 SHDN and TXFIN ..................................................................................................................................................... 26 Temperature Measurement ...................................................................................................................................... 26 Diode Faults .............................................................................................................................................................. 26 Temperature Compensation ..................................................................................................................................... 26 Alarms and Warning Flags........................................................................................................................................ 31 Control and Status I/O .............................................................................................................................................. 31 System Timing ............................................................................................................................................................. 32 Warm Resets ............................................................................................................................................................ 35 Power-On Hour Meter ............................................................................................................................................... 35 Test and Calibration Features .................................................................................................................................. 35 Serial Port Operation ................................................................................................................................................ 36 Page Writes .............................................................................................................................................................. 36 Acknowledge Polling ................................................................................................................................................. 37 Write Protection and Data Security ........................................................................................................................... 37 OEM Password ..................................................................................................................................................... 37 User Password ..................................................................................................................................................... 37 Detailed Register Descriptions .................................................................................................................................. 38 Alarm Threshold Registers ........................................................................................................................................ 38 Warning Threshold Registers .................................................................................................................................... 43 ADC Result Registers ................................................................................................................................................. 49 August 2004 3 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Alarm Flags .................................................................................................................................................................. 52 Warning Flags .............................................................................................................................................................. 53 Applications Information ............................................................................................................................................ 69 Controlling Laser Diode Bias ..................................................................................................................................... 69 Choosing CCOMP ........................................................................................................................................................ 70 Measuring Laser Bias Current .................................................................................................................................. 70 Interfacing To Laser Drivers...................................................................................................................................... 70 SY88912 3.3V 3.2Gbps SONET/SDH Laser Driver ................................................................................................. 71 Modulation Current ................................................................................................................................................... 71 SY88932 3.3V 3.2Gbps SONET/SDH Laser Driver ................................................................................................. 71 SY89307 5.0V/ 3.3V 2.5Gbps VCSEL Driver ........................................................................................................... 72 Laser Drivers Programmed via a Sink Current ......................................................................................................... 72 Drivers with Monitor Outputs .................................................................................................................................... 72 Shutdown Output ...................................................................................................................................................... 72 Temperature Sensing ............................................................................................................................................... 73 Remote Sensing ....................................................................................................................................................... 73 Minimizing Errors ........................................................................................................................................................ 73 Self-Heating .............................................................................................................................................................. 73 Series Resistance with External Temperature Sensor ............................................................................................. 74 XPN Filter Capacitor Selection ................................................................................................................................. 74 XPN Layout Considerations ...................................................................................................................................... 74 Layout Considerations .............................................................................................................................................. 75 Small Form-Factor Pluggable (SFP) Transceivers............................................................................................... 75 Power Supplies ......................................................................................................................................................... 75 Using the MIC3001 In a 5V System .......................................................................................................................... 75 Package Information ................................................................................................................................................... 76 August 2004 4 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 List of Figures Figure 1. MIC3001 Block Diagram ................................................................................................................................................... 17 Figure 2. Analog-to-Digital Converter Block Diagram....................................................................................................................... 18 Figure 3. RXPOT Block Diagram ..................................................................................................................................................... 22 Figure 4. MIC3001 APC and Modulation Control Block Diagram .................................................................................................... 22 Figure 5. Programmable Feedback Resistor .................................................................................................................................... 22 Figure 6. Transmitter Configurations Supported by MIC3001 ......................................................................................................... 23 Figure 7. VMOD Configured as Voltage Output with Gain ................................................................................................................. 23 Figure 9. Fault Comparator Logic..................................................................................................................................................... 25 Figure 10. Saturation Detector ......................................................................................................................................................... 26 Figure 11. RXLOS Comparator Logic .............................................................................................................................................. 26 Figure 12. Examples of LUTOFF Operation ..................................................................................................................................... 29 Figure 13. Temperature Compensation Examples ........................................................................................................................... 30 Figure 14. Control and Status I/O Logic ........................................................................................................................................... 32 Figure 15. Transmitter ON-OFF Timing ........................................................................................................................................... 32 Figure 16. Initialization Timing with TXDISABLE Asserted .............................................................................................................. 32 Figure 17. Initialization Timing with TXDISABLE Not Asserted ........................................................................................................ 33 Figure 18. Loss-of-Signal (LOS) Timing ........................................................................................................................................... 33 Figure 20. Successfully Clearing a Fault Condition .......................................................................................................................... 34 Figure 21. Unsuccessful Attempt to Clear a Fault ............................................................................................................................ 34 Figure 22. Write Byte Protocol ......................................................................................................................................................... 36 Figure 23. Read Byte Protocol ......................................................................................................................................................... 36 Figure 24. Read_Word Protocol ....................................................................................................................................................... 36 Figure 25. Four-Byte Page_White Protocol ...................................................................................................................................... 37 Figure 26. Example APC Circuit for Common-Cathode TOSA ........................................................................................................ 69 Figure 27. Example APC Circuit for Common Anode TOSA ............................................................................................................ 69 Figure 28. Slew Rate vs. CCOMP Value ............................................................................................................................................. 70 Figure 29. Open Loop Unity-Gain Bandwidth vs. CCOMP ................................................................................................................. 70 Figure 31. Controlling the SY88932 Modulation Current .................................................................................................................. 71 Figure 32. Controlling the SY89307 Modulation Current .................................................................................................................. 72 Figure 33. Controlling the Modulation Current via a Sink Current ................................................................................................... 72 Figure 34. Redundant Switch Circuits .............................................................................................................................................. 73 Figure 35. Guard Traces and Kelvin Return for Remote Thermal Diode......................................................................................... 75 Figure 36. Typical SFP Control and Status I/O Signal Routing (not to scale) ................................................................................. 75 Figure 37. Power Supply Routing and Bypassing ............................................................................................................................ 75 August 2004 5 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 List of Tables Table 1. MIC3001 Address Map, Serial Address = A0h ................................................................................................ 15 Table 2. MIC3001 Address Map, Serial Address = A2h ................................................................................................ 15 Table 3. Temperature Compensation Tables, Serial Address = A4h ............................................................................ 15 Table 4. OEM Configuration Registers, Serial Address = A6h ...................................................................................... 16 Table 5. A/D Input Signal Ranges and Resolutions ...................................................................................................... 18 Table 6. VAUX Input Signal Ranges and Resolutions ..................................................................................................... 18 Table 7. LSB Values of Offset Coefficients ................................................................................................................... 20 Table 8. Internal Calibration Coefficient Memory Map – Part I ..................................................................................... 21 Table 9. Internal Calibration Coefficient Memory Map – Part II .................................................................................... 21 Table 10. Shutdown State of SHDN vs. Configuration Bits ......................................................................................... 24 Table 11. Shutdown State of VBIAS vs. Configuration Bits ............................................................................................ 24 Table 12. Shutdown State of VMOD vs. Configuration Bits ............................................................................................ 24 Table 13. Temperature Compensation Look-up Tables, Serial Address I2CADR + 4h ............................................... 27 Table 14. APC Temperature Compensation Look-Up Table, Serial Address 12C ADR+4h ......................................... 28 Table 15. VMOD Temperature Compensation Look-Up Table, Serial Address 12C ADR+4h ........................................ 28 Table 16. IBIAS Comparator Temperature Compensation Look-Up Table, Serial Address 12C ADR+4h ...................... 28 Table 17. BIAS Current High Alarm Temperature Compensation Table, Serial Address 12C ADR+4h ....................... 28 Table 18. Range of Temperature Compensation Table vs. LUTOFF .......................................................................... 29 Table 19. MIC3001 Events ............................................................................................................................................ 31 Table 20. Power-On Hour Meter Result Format ........................................................................................................... 35 Table 21. Test and Diagnostic Features ....................................................................................................................... 35 Table 22. Typical Values for CCOMP ............................................................................................................................... 70 Table 23. Control Range of SY88912 Modulation Control Circuit ............................................................................... 71 Table 24. Transistors Suitable for Use as Remote Diodes .......................................................................................... 73 Table 25. Contributors to Self-Heating .......................................................................................................................... 74 August 2004 6 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Pin Configuration 24-Pin QFN Pin Description Pin Number Pin Name 1 FB 2 VMPD Analog Input. Multiplexed A/D converter input for monitoring transmitted optical power via a monitor photodiode. In most applications, VMPD will be connected directly to FB. The input range is 0 - VREF or 0 - VREF/4 depending on the setting of the APC configuration bits 3 GNDA Ground return for analog functions. 4 VDDA Power supply input for analog functions. 5 VILD– Analog Input. Reference terminal for the multiplexed pseudo-differential A/D converter inputs for monitoring laser bias current via a sense resistor (VILD+ is the sensing input). Tie to VDD or GND to reference the voltage sensed on VILD+ to VDD or GND respectively. Limited common-mode voltage range, see “Applications Information” section for more details. 6 VILD+ Analog Input. Multiplexed A/D input for monitoring laser bias current via a sense resistor (signal input); accommodates inputs referenced to VDD or GND (see pin 5 description). Limited common-mode voltage range, see “Applications Information” section for more details. 7 SHDN (TXFIN) Digital output; Programmable polarity. When used as shutdown output (SHDN), asserted at the detection of a fault condition that can be used to activate a second series transistor in the laser current path, enhancing protection against single-point failures. When programmed as TXFIN, it is an input for external fault signals to be ORed with the internal fault sources to drive TXFAULT. 8 SHDN (TXFIN) Analog Input. Multiplexed A/D converter input for monitoring received optical power. The input range is 0 to VREF. A 5-bit programmable EEPOT on this pin provides for coarse calibration and ranging of the RX power measurement. 9 XPN 10 TXFAULT August 2004 Pin Function Analog Input. Feedback voltage for the APC loop op-amp. Polarity and scale are programmable via the APC configuration bits. Connect to VBIAS if APC is not used. Analog Input/Output. Optional connection to an external PN junction for sensing temperature at a remote location. The Zone bit in OEMCFG1 determines whether temperature is measured using the on-chip sensor or the remote PN junction. Digital Output; Open-Drain. A high level indicates a hardware fault impeding transmitter operation. The state of this input is always reflected in the TXFLT bit. 7 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Pin Description Pin Number Pin Name Pin Function 11 TXDISABLE 12 DATA 13 CLK Digital Input; Serial bit clock input. 14 VIN If bit 4 (IE) in USRCTL register is set to 0 (default), this pin is configured as analog input. If IE bit is set to 1, this pin is configured as open-drain output. Analog Input: Multiplexed A/D input for monitoring supply voltage. 0V to 5.5V input range. Open-drain output: outputs the internally generated interrupt signal /INT. 15 RSIN Digital Input; Rate Select Input; ORed with rate select bit to determine the state of the RSOUT pin. The state of this pin is always reflected in the RSEL bit. 16 GNDD Ground return for digital functions. 17 NC Digital Input; Active High. The transmitter is disabled when this line is high or the STXDIS bit is set. The state of this input is always reflected in the TXDIS bit. Digital I/O; Open-drain. Bi-directional serial data input/output. No connection. This pin is used for test purposes and must be left unconnected. 18 VDDD Power supply input for digital functions. 19 RXLOS Digital Output; Active-High/Open-Drain. Indicates the loss of the received signal as indicated by a level of received optical power below the programmed RXLOS comparator threshold; may be wire-ORed with external signals. Low indicates normal operation. RXLOS is deasserted when VRX > LOSFLTn. The LOS bit reflects the state of RXLOS whether driven by the MIC3001 or an external circuit. 20 RSOUT (GPO) Digital Output. Open-Drain or push-pull. When used as rate select output, this output is controlled by the SRSEL bit ORed with RSIN input and is open drain only. When used as a general-purpose, non-volatile output, it is controlled by the GPO configuration bits in OEMCFG3. 21 COMP Analog Output, compensation terminal. Connect a capacitor between this pin and GNDA or VDDA with appropriate value to tune the APC loop time constant to a desirable value. 22 VBIAS Analog Output. Buffered DAC output capable of sourcing or sinking up to 10mA under control of the APC function to drive an external transistor for laser diode D.C. bias. The output and feedback polarity are programmable to accommodate either a NPN or an PNP transistor to drive a common-anode or common-cathode laser diode. 23 VMOD– Analog Input. Inverting terminal of VMOD buffer op-amp. Connect to VMOD+ (gain = 1) or feedback resistors network to set a different gain 24 VMOD+ Analog Output. Buffered DAC output to set the modulation current on the laser driver IC. Operates with either a 0– VREF or a (VDD–VREF) – VDD output swing so as to generate either a ground-referenced or a VDD referenced programmed voltage. A simple external circuit can be used to generate a programmable current for those drivers that require a current rather than a voltage input. See “Applications Information” section for more details. August 2004 8 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Absolute Maximum Ratings(1) Operating Ratings(2) Power Supply Voltage, VDD ................................. +3.8V Voltage on CLK, DATA, TXFAULT, VIN, RXLOS, DISABLE, RSIN ................................. –0.3V to +6.0V Voltage On Any Other Pin ............... –0.3V to VDD+0.3V Power Dissipation, TA = 85°C ............................... 1.5W Junction Temperature (TJ) .................................. 150°C Storage Temperature (TS).................. –65°C to +150°C Power Supply Voltage, VDDA/VDDD ..... +3.0V to +3.6V Ambient Temperature Range (TA) ... –40°C to +105°C Package Thermal Resistance QFN (θJA) ............................................... 43°C/W ESD Ratings(3) Human Body Model ............................................. 2kV Machine Model .................................................. 300V Soldering (20sec) .................................................260ºC Electrical Characteristics For typical values, TA = 25°C, VDDA = VDDD = +3.3V, unless otherwise noted. Bold values are guaranteed for +3.0V ≤ (VDDA = VDDD) ≤ 3.6V, T(min) ≤ TA ≤ T(max)(8) Symbol Parameter Condition Min Typ Max Units CLK = DATA = VDDD = VDDA; TXDISABLE low; all DACs at full-scale; all A/D inputs at full-scale; all other pins open. 2.3 3.5 mA CLK = DATA = VDDD = VDDA; TXDISABLE high; FLTDAC at full-scale; all A/D inputs at full-scale; all other pins open. 2.3 3.5 mA 2.9 2.98 V Power Supply IDD Supply Current VPOR Power-on Reset Voltage All registers reset to default values; A/D conversions initiated. VUVLO Under-Voltage Lockout Threshold Note 5 VHYST Power-on Reset Hysteresis Voltage tPOR Power-on Reset Time VREF Reference Voltage ∆VREF/∆VDDA Voltage Reference Line Regulation 2.5 VDD > VPOR(4) 1.210 2.73 V 170 mV 50 µs 1.225 1.24 0 1.7 V mV/V Temperature-to-Digital Converter Characteristics Local Temperature Measurement Error –40°C ≤ TA ≤ +105°C(6) ±1 ±3 °C Remote Temperature Measurement Error –40°C ≤ TA ≤ +105°C(6) ±1 ±3 °C tCONV Conversion Time Note 4 60 ms tSAMPLE Sample Period 100 ms 400 µA Remote Temperature Input, XPN IF Current to External Diode(4) XPN at high level, clamped to 0.6V. XPN at low level, clamped to 0.6V. August 2004 9 192 7 12 µA M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Voltage-to-Digital Converter Characteristics (VRX, VAUX, VBIAS, VMPD, VILD±) Symbol Parameter Condition Voltage Measurement Error –40°C ≤ TA ≤ +105°C(6) Min Typ Max Units ±1 ±2.0 %fs tCONV Conversion Time Note 4 10 ms tSAMPLE Sample Period Note 4 100 ms 5.5 V Voltage Input, VIN (Pin 14 used as an ADC Input) VIN Input Voltage Range –0.3 ≤ VDD ≤ 3.6V ILEAK Input Current VIN = VDD or GND; VAUX = VIN CIN nput Capacitance GNDA 55 µA 10 pF Digital-to-Voltage Converter Characteristics (VMOD, VBIAS) Accuracy –40°C ≤ TA ≤ +105°C(6) tCONV Conversion Time Note 4 DNL Differential Non-linearity Error Note 4 ±1 ±0.5 2.0 %fs 20 ms ±1 LSB VREF/4 mV ±1 µA Bias Current Sense Inputs, VILD+, VILD– VILD Differential Input Signal Range, | VILD+ – VILD– | IIN+ VILD+ input current IIN– VILD– input current VILD– referred to VDDA +150 µA | VILD+ – VILD– | = 0.3V VILD– referred to GND -150 µA 10 pF 1 MHz 1 µV/°C CIN 0 Input Capacitance APC Op Amp, FB, VBIAS, COMP GBW Gain Bandwidth Product TCVOS Input Offset Voltage Temperature Coefficient(4) VOUT Output Voltage Swing CCOMP = 20pF; Gain = 1 IOUT = 10mA, SRCE bit = 1 GNDA 1.25 V IOUT = -10mA, SRCE bit = 0 VDDA -1.25 VDDA V ISC Output Short-Circuit Current tSC Short Circuit Withstand Time TJ ≤ 150°C(4) PSRR Power Supply Rejection Ratio CCOMP = 20pF; Gain = 1, to GND 55 CCOMP = 20pF; Gain = 1, to VDD 40 55 mA sec AMIN Minimum Stable Gain CCOMP = 20pF, Note 4 ∆V/∆t Slew Rate CCOMP = 20pF; Gain = 1 ∆RFB dB 1 V/V 3 V/µs Internal Feedback Resistor Tolerance ±20 % ∆RFB/∆t Internal Feedback Resistor Temperature Coefficient 25 ppm/C ISTART Laser Start-up Current Magnitude START = 01h 0.375 mA START = 02h 0.750 mA START = 04h 1.500 mA START = 08h 3.000 mA 10 pF CIN Pin Capacitance August 2004 10 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Electrical Characteristics Symbol Parameter Condition Min Typ Max Units VMOD Buffer Op-Amp, VMOD+, VMOD– CCOMP = 20pF; Gain = 1 1 MHz 1 µV/°C GBW Gain Bandwidth TCVOS Input Offset Voltage Temperature Coefficient IBIAS VMOD– Input Current VOUT Output Voltage Swing ISC Output Short-Circuit Current tSC Short Circuit Withstand Time TJ ≤ 150°C(4) PSRR Power Supply Rejection Ratio CCOMP = 20pF; Gain = 1, to GND 65 dB CCOMP = 20pF; Gain = 1, to VDD 44 dB ±0.1 IOUT = ±1mA GNDA+75 ±1 µA VDDA-75 mV 35 mA sec AMIN Minimum Stable Gain CCOMP = 20pF ∆V/∆T Slew Rate CCOMP = 20pF; Gain = 1 CIN Pin Capacitance 1 V/V 1 V/µs 10 pF Control and Status I/O, TXDISABLE, TXFAULT, RSIN, RSOUT(GPO), SHDN(TXFIN), RXLOS, /INT VIL Low Input Voltage VIH High Input Voltage VOL Low Output Voltage IOL ≤ 3mA 0.3 V VOH High Output Voltage (applies to SHDN only) IOH ≤ 3mA VDDD–0.3 V ILEAK Input Current ±1 µA CIN Input Capacitance 0.8 2.0 V V 10 pF Transmit Optical Power Input, VMPD VIN Input Voltage Range Note 4 VRX Input Signal Range BIASREF=0 GNDA VDDA–VREF BIASREF=1 CIN Input Capacitance ILEAK Input Current Note 4 VDDA V VREF V VDDA V 10 pF ±1 µA GNDA VDDA V 0 VREF V Received Optical Power Input, VRX, RXPOT Input Voltage Range VRX Valid Input Signal Range (ADC Input Range) RRXPOT(32) End-to-End Resistance ∆RXPOT Note 4 RXPOT = 1Fh 32 KΩ Resistor Tolerance ±20 % ∆RXPOT/∆T Resistor Temperature Coefficient 25 ppm/C ∆VRX/VRXPOT Divider Ratio Accuracy 00 ≤ RXPOT ≤ 1Fh ILEAK Input Current RXPOT = 0 (disconnected) CIN Input Capacitance Note 4 ILEAK Input Current August 2004 -5 +5 % ±1 µA 10 pF ±1 11 µA M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Electrical Characteristics Symbol Parameter Condition Min Typ Max Units Control and Status I/O Timing, TXFAULT, TXDISABLE, RSIN, RSOUT, and RXLOS tOFF TXDISABLE Assert Time From input asserted to optical output at 10% of nominal, CCOMP = 10nF. 10 µs tON TXDISABLE De-assert Time From input de-asserted to optical output at 90% of nominal, CCOMP = 10nF. 1 ms tINIT Initialization Time From power on or transmitter enabled to optical output at 90% of nominal and TX_FAULT de-asserted.(4) 300 ms tINIT2 Power-on Initialization Time From power on to APC loop enabled. 200 ms tFAULT TXFAULT Assert Time From fault condition to TXFAULT assertion.(4) 95 µs tRESET Fault Reset Time Length of time TXDISABLE must be asserted to reset fault condition. tLOSS_ON RXLOS Assert Time From loss of signal to RXLOS asserted. 95 µs tLOSS_OFF RXLOS De-assert Time From signal acquisition to LOS deasserted. 100 µs tDATA Analog Parameter Data Ready From power on to valid analog parameter data available.(4) 400 ms tPROP_IN TXFAULT, TXDISABLE, RXLOS, RSIN Input Propagation Time Time from input change to corresponding internal register bit set or cleared.(4) 1 µs tPROP_OUT TXFAULT, RSOUT, /INT Output Propagation Time From an internal register bit set or cleared to corresponding output change.(4) 1 µs 0.525 ms +3 %/F.S. 10 µs Fault Comparators φFLTTMR Fault Suppression Timer Clock Period 0.475 Note 4 Accuracy 0.5 -3 tREJECT Glitch Rejection Maximum length pulse that will not cause output to change state.(4) VSAT Saturation Detection Threshold High level 95 %VDDA Low level 5 %VDDA 4.5 µs Power-On Hour Meter Timebase Accuracy Resolution 0°C ≤ TA ≤ +70°C(4) +5 -5 % –40°C ≤ TA ≤ +105°C +10 -10 % Note 4 10 hours Non-Volatile (FLASH) Memory tWR Write Cycle Time(7) Data Retention Endurance August 2004 13 From STOP of a one to four-byte write transaction.(4) Minimum Permitted Number Write Cycles 12 ms 100 years 10,000 cycles M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Serial Data I/O Pin, Data Symbol Parameter Condition VOL Low Output Voltage VIL Low Input Voltage VIH High Input Voltage ILEAK Input Current CIN Input Capacitance Min Typ Max Units IOL = 3mA 0.4 V IOL = 6mA 0.6 V 0.8 2.1 ±1 Note 4 V V 10 µA pF Serial Clock Input, CLK VIL Low Input Voltage 2.7V ≤ VDD ≤ 3.6V VIH High Input Voltage 2.7V ≤ VDD ≤ 3.6V ILEAK Input Current CIN Input Capacitance Serial Interface Timing 0.8 2.1 V ±1 Note 4 V 10 µA pF (4) t1 CLK (clock) Period 2.5 µs t2 Data In Setup Time to CLK High 100 ns t3 Data Out Stable After CLK Low 300 ns t4 Data Low Setup Time to CLK Low Start Condition 100 ns t5 Data High Hold Time After CLK High Stop Condition 100 ns tDATA Data Ready Time From power on to completion of one set of ADC conversions; analog data available via serial interface. 400 ms Notes: 1. Exceeding the absolute maximum rating may damage the device. 2. The device is not guaranteed to function outside its operating rating. 3. Devices are ESD sensitive. Handling 4. precautions recommended. 5. Guaranteed by designing and/or testing of related parameters. Not 100% tested in production. 6. The MIC3000 will attempt to enter its shutdown state when VDD falls below VUVLO. This operation requires time to complete. If the supply voltage falls too rapidly, the operation may not be completed. 7. Does not include quantization error. 8. The MIC3001 will not respond to serial bus transactions during an EEPROM write-cycle. The host will receive a NACK during tWR. 9. Final test on outgoing product is performed at TA = +25°C. August 2004 13 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Timing Diagram Serial Interface Timing August 2004 14 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Address Map Address(s) Field Size (Bytes) Name Description 0 –95 96 Serial ID defined by SEP MSA G-P NVRAM; R/W under valid OEM password. 96 – 127 32 Vendor Specific Vendor specific EEPROM 128 – 255 128 Reserved Reserved for future use. G-P NVRAM; R/W under valid OEM password. Table 1. MIC3001 Address Map, Serial Address = A0h Address(s) Field Size (Bytes) HEX DEC Name Description 00-27 0-39 40 Alarm and Warning Threshold High/low limits for warning and alarms; writeable using OEM p/w; read-only otherwise. 28-37 40-55 16 Reserved Reserved – do not write; reads undefined. 38-5B 56-91 36 Calibration Constants Numerical constants for external calibration; writeable using OEM p/w; read-only otherwise. 5C-5E 92-94 3 Reserved Reserved – do not write; reads undefined. 5F 95 1 Checksum G-P NVRAM; writeable using OEM p/w; ready only otherwise. 60-69 96-105 10 Analog Data Real time analog parameter data. 6A-6D 106-109 4 Reserved Reserved – do not write; reads undefined. 6E 110 1 Control/Status Bits Control and status bits. 6F 111 1 Reserved Reserved – do not write; reads undefined. 70-71 112-113 2 Alarm Flags Alarm status bits; read only. 72-73 114-115 2 Reserved Reserved – do not write; reads undefined. 74-75 116-117 2 Warning Flags Warning status bits; read only. 76-77 118-119 2 Reserved Reserved – do not write; reads undefined. 78-7B 120-123 4 OEMPW OEM password entry field. 7C-7F 124-127 4 Vendor Specific Vendor specific. Reserved – do not write; reads undefined. 80-F7 128-247 120 User Scratchpad User writeable EEPROM. G-P NVRAM; R/W using any valid password. F8-F9 248-249 2 Reserved Reserved – do not write; reads undefined. FA 250 1 USRPWSET User password setting; read/write using any p/w; returns zero otherwise. FB 251 1 USRPW Entry field for user password. FC-FD 252-253 2 POH Power-on hour meter result; ready only. FE 254 1 Data Ready Flags Data ready bits for each measured parameter; read only. FF 255 1 User Control End-user control and status bits. Table 2. MIC3001 Address Map, Serial Address = A2h Address(s) HEX DEC 00-3F 0-63 40-7F 80-BF C0-FF Field Size (Bytes) Name Description 64 APCLUTn A.P.C temperature compensation L.U.T. 64-127 64 MODLUTn VMOD temperature compensation L.U.T. 128-191 64 IFLTUT Bias current fault threshold temperature compensation L.U.T. 192-255 64 EOLLUTn Bias current high alarm threshold temperature compensation L.U.T. Table 3. Temperature Compensation Tables, Serial Address = A4h August 2004 15 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Address(s) HEX DEC Field Size (Bytes) 00 0 40 OEMCFG0 Control/status bits 01 1 16 OEMCFG1 Control/status bits 02 2 36 OEMCFG2 Control/status bits 03 3 3 APCSET0 APC setpoint 0 04 4 1 APCSET1 APC setpoint 1 05 5 10 APCSET2 APC setpoint 2 06 6 4 MODSET Nominal modulation DAC setpoint 07 7 1 IBFLT Bias current fault-comparator threshold 08 8 1 TXPFLT TX power fault threshold 09 9 2 LOSFLT RX LOS fault-comparator threshold 0A 10 2 FLTTMR Fault comparator masking interval timer setting 0B 11 2 FLTMSK Fault source mask bits 0C-0F 12-15 2 OEMPWSET Password for access to OEM areas 10 16 4 OEMCAL0 OEM calibration register 0 11 17 4 OEMCAL1 OEM calibration register 1 12 18 120 LUTINDX Look-up table index read-back 13 19 2 RESERVED Reserved – do not write; reads undefined. 14 20 1 APCDAC Reads back current APC DAC setting 15 21 1 MODDAC Reads back current modulation DAC setting 16 22 2 OEMREAD Reads back OEM calibration data 17 23 1 LOSFLTn LOS De-assert threshold 18 24 1 RXPOT RXPOT tap selection 19 25 1 OEMCFG4 I START selection bits 1A-1F 26-31 6 RESERVED Reserved – do not write; reads undefined. 20-27 32-39 8 POHDATA Power-on hour meter scratchpad 28-47 40-71 32 RXLUT RX power calibration look-up table 48-49 72-73 2 RESERVED Reserved – do not write; reads undefined. 4A-57 74-87 18 CAL Internal calibration slope/offset data 59-7D 88-125 37 RESERVED Reserved – do not write; reads undefined. 7E-FD 126-253 128 SCRATCH OEM scratchpad area FE 254 1 MFG_ID Manufacturer identification (Micrel = 42) FF 255 1 DEV_ID Device and die revision Name Description Table 4. OEM Configuration Registers, Serial Address = A6h August 2004 16 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Block Diagram Figure 1. MIC3001 Block Diagram MIC3000 Capability In general, the MIC3001 is completely hardware and software backward compatible with the MIC3000. Every feature available in the MIC3000 is still present in the MIC3001. New features have, of course, been added. The following differences between the MIC3000 and MIC3001 would be evident to host software: 1. Faults do not set alarm or warning bits as in the MIC3000. 2. RXOPI at register address 69h at serial address x2h now contains four bits of data rather then being fixed at zero as in the MIC3000. Analog-to-Digital Converter/Signal Monitoring A block diagram of the monitoring circuit is shown below. Each of the five analog parameters monitored by the MIC3001 are sampled in sequence. All five parameters are sampled and the results updated within the tCONV internal given in the “Electrical Characteristics” section. In OEM, Mode, the channel that is normally used to measure VIN may be assigned to measure the level of the VDDA pin or one of five other nodes. This provides a kind of analog loopback for debug and test purposes. The VAUX bits in OEMCFG0 control which voltage source is being sampled. The various VAUX channels are level-shifted differently depending on the signal source, resulting in different LSB values and signal ranges. See Table 5. August 2004 17 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Figure 2. Analog-to-Digital Converter Block Diagram Channel ADC Resolution (bits) TEMP 8 VAUX 8 VMPD 8 VILD 8 VRX 12 Conditions (1) Input Range (V) LSB N/A 1°C See Table 6 GAIN = 0; BIASREF = 0 GNDA - VREF 4.77mV GAIN = 0; BIASREF = 1 VDDA – (VDDA – VREF) GAIN = 1; BIASREF = 0 GNDA - VREF/4 1.17mV /4 GAIN = 1; BIASREF = 1 VDDA – (VDDA – VREF ) VILD- = VDDA VDDA – (VDDA – VREF) VILD- = GNDA GNDA - VREF RXPOT = 00 0 - VREF 4.77mV 0.298mV Table 5. A/D Input Signal Ranges and Resolutions Note: 1. Assumes typical VREF value of 1.22V. Channel (1) VAUX [2:0] Input Range (V) LSB (mV) VIN 000 = 00h 0.5V to 5.5V 25.6mV VDDA 0001 = 01h 0.5V to 5.5V 25.6mV VBIAS 010 = 02h 0.5V to 5.5V 25.6mV VMOD 011 = 03h 0.5V to 5.5V 25.6mV APCDAC 100 = 04h 0V to VREF 4.77mV MODDAC 101 = 05h 0V to VREF 4.77mV FLTDAC 110 = 06h 0V to VREF 4.77mV Table 6. VAUX Input Signal Ranges and Resolutions Note: 1. Assumes typical VREF value of 1.22V. August 2004 18 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. Internal/External Calibration The default mode of calibration in the MIC3001 is external calibration, for which INTCAL bit (bit 0 in OEMCF3 register) is set to 0. This mode is backward compatible with MIC3000. The internal calibration mode is selected by setting INTCAL bit to 1. A/ External Calibration The voltage and temperature values returned by the MIC3001’s A/D converter are internally calibrated. The binary values of TEMPh:TEMPl and VOLTh:VOLTl are in the format called for by SFF-8472 under Internal Calibration. SFF-8472 calls for a set of calibration constants to be stored by the transceiver OEM at specific non-volatile memory locations, refer to SFF-8472 specifications for memory map of calibration coefficient. The MIC3001 provides the non-volatile memory required for the storage of these constants. The Digital Diagnostic Monitoring Interface specification should be consulted for full details. Slopes and offsets are stored for use with voltage, temperature, bias current, and transmitted power measurements. Coefficients for a fourth-order polynomial are provided for use with received power measurements. The host system can retrieve these constants and use them to process the measured data. Since voltage and temperature require no calibration, the corresponding slopes should generally be set to unity and the offsets to zero. Voltage The voltage values returned by the MIC3001’s A/D converter are internally calibrated. The binary values of VOLTh:VOLTl are in the format called for by SFF-8472 under Internal Calibration. Since VINh:VINl requires no processing, the corresponding slope should be set to unity and the offset to zero. MIC3001 (1) The value of the least significant bit (LSB) of IBIASh is given by: (2) Per SFF-8472, the value of the bias current LSB is 2µA. The conversion factor, “slope”, needed is therefore: The tolerance of the sense resistor directly impacts the accuracy of the bias current measurement. It is recommended that the sense resistor chosen be 1% accurate or better. The offset correction, if needed, can be determined by shutting down the laser, i.e., asserting TXDISABLE, and measuring the bias current. Any nonzero result gives the offset required. The offset will be equal and opposite to the result of the “zero current” measurement. TX Power Transmit power is sensed via an external sense resistor as a voltage appearing at VMPD. It is assumed that this voltage is generated by a sense resistor carrying the monitor photodiode current. In most applications, the signal at VMPD will be feedback voltage on FB. The VMPD voltage may be measured relative to GND or VDDA depending on the setting of the BIASREF bit in OEMCFG1. The value returned by the A/D is therefore a voltage analogous to transmit power. The binary value in TXOPh (TXOPl is always zero) is related to transmit power by: Temperature The temperature values returned by the MIC3001’s A/D converter are internally calibrated. The binary values of TEMPh:TEMPl are in the format called for by SFF-8472 under Internal Calibration. Since TEMPh:TEMPl requires no processing, the corresponding slope should be set to unity and the offset to zero. Bias Current Bias current is sensed via an external sense resistor as a voltage appearing at VILD+ and VILD-. The value returned by the A/D is therefore a voltage analogous to bias current. Bias current, IBIAS, is simply VVILD/RSENSE. The binary value in IBIASh (IBIASl is always zero) is related to bias current by: August 2004 (3) For a given implementation, the value of RSENSE is known. It is either the value of the external resistor or the chosen value of RFB used in the application. The constant, K, will likely have to be determined through experimentation or closed-loop calibration, as it depends on the monitoring photodiode responsivity and coupling efficiency. It should be noted that the APC circuit acts to hold the transmitted power constant. The value of transmit power reported by the circuit should only vary by a small amount as long as APC is functioning correctly. 19 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 RX Power Received power is sensed as a voltage appearing at VRX. It is assumed that this voltage is generated by a sense resistor carrying the receiver photodiode current. (4) For a given implementation, the constant, K, will likely have to be determined through experimentation or closedloop calibration, as it depends on the gain and efficiencies of the components upstream. In SFF-8472 implementations, the external calibration constants can describe up to a fourth-order polynomial in case K is nonlinear. B/ Internal Calibration If the INTCAL bit in OEMCFG3 is set to 1 (internal calibration selected), the MIC3001 will process each piece of data coming out of the A/D converter before storing the result in memory. Linear slope/offset correction will be applied on a per-channel basis to the measured values for voltage, bias current, TX power, and RX power. Only offset correction is applied to temperature. The user must store the appropriate slope/offset parameters in memory at the time of transceiver calibration. In the case of RX power, a look-up table is provided that implements eight-segment piecewise-linear correction. This correction may be performed as temperature compensation or as simple slope/offset correction. If static slope/offset correction for RX power is desired, the eight coefficient sets can simply be made the same. The memory maps for these coefficients are shown in Table 8 and Table 9. The slopes allow for the correction of gain errors. Each slope coefficient is an unsigned, sixteen-bit, fixed-point binary number in the format: [mmmmmmmm.llllllll], where m is a data bit (5) in the most-significant byte and l is a data bit in the least significant byte Slopes are always positive. The binary point is in between the two bytes, i.e., between bits 7 and 8. This provides a numerical range of 1/256 (0.00391) to 255 in steps of 1/256. The most significant byte is always stored in memory at the lower numerical address. The offsets correct for constant errors in the measured data. Each offset is a signed, sixteen-bit, fixed-point binary number. The bit-weights of the offsets are the same as that of the final results. In the case of temperature, the offset’s least significant byte (LSB) is always zero since the MIC3001 does not deal with fractional temperature values. The sixteen bit offsets provide a numerical range of –32768 to +32767 for voltage, bias current, transmit power, and receive power. August 2004 The value returned by the A/D is therefore a voltage analogous to received power. The binary value in RXOPh (RXOPl is always zero) is related to received power by: The numerical range for the temperature offset is –32513 (–128°) to +32512 (+127°) in increments of 256 (1°). The format for offsets is: [Smmmmmmmllllllll], where S is the sign bit (6) (1 = positive, 0 = negative), m is a data bit in the most-significant byte and l is a data bit in the least significant byte The most significant byte is always stored in memory at the lower numerical address. Calibration of voltage, bias current, and TX power are performed using the following calculation: RESULTn = ADC_RESULTn x SLOPEn + (7) OFFSETn Calibration of temperature is performed using the following calculation: RESULT = ADC_RESULT + OFFSET (8) Calibration of RX power is performed using the following calculation: RESULT = ADC_RESULT x SLOPE(m) + (9) OFFSET(m) where m is the appropriate value from the RX power calibration look-up table. The results of these calculations are rounded to sixteen bits in length. If the seventeenth most significant bit is a one, the result is rounded up to the next higher value. If the seventeenth most significant bit is zero, the upper sixteen bits remain unchanged. The bit-weights of the offsets are the same as that of the final results. For SFF-8472 compatible applications, these bit-weights are given in Table 7. Parameter Magnitude of LSB Temperature 1.0°C (1) Voltage 100µV Bias Current 2µA TX Power 0.1µW RX Power 0.1µW Table 7. LSB Values of Offset Coefficients Note: 1. The LSBytes of the temperature is always zero. 20 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Address(s) HEX DEC Field Size Name Description 48-49 72-73 2 RESERVED 4A-4B 74-75 2 TOFFh:TOFFl Reserved. (There is no slope for temperature.) Do not write; reads undefined. Temperature offset; signed fixed point; LSB is always zero; MSB is at lower physical address. 4C-4D 76-77 2 VSLPh:VSLPl Voltage slope; unsigned fixed-point; MSB is at lower physical address. 4E-4F 78-79 2 VOFFh:VOFFl Voltage offset; signed fixed point; MSB is at lower physical address. 50-61 80-81 2 ISLPh:ISLPl Bias current slope; unsigned fixed-point; MSB is at lower physical address. 52-63 82-83 2 IOFFh:IOFFl Bias current offset; signed fixed point; MSB is at lower physical address. 54-65 84-85 2 TXSLPh: TXSLPl TX power slope; unsigned fixed-point; MSB is at lower physical address. 56-67 86-87 2 TXOFFh: TXOFFl TX power offset; signed fixed point; MSB is at lower physical address. Table 8. Internal Calibration Coefficient Memory Map – Part I Address(s) Field Size HEX DEC Name Description 28-29 40-41 2 RXSLP0h: RXSLP0l RX power slope 0; unsigned fixed-point; MSB is at lower physical address. 2A-2B 42-43 2 RXOFF0h: RXOFF0l RX power offset 0; signed twos-complement; MSB is at lower physical address. 2C-2D 44-45 2 RXSLP1h: RXSLP1l RX power slope 1; unsigned fixed-point; MSB is at lower physical address. 2E-2F 46-47 2 RXOFF1h: RXOFF1l RX power offset 1; signed twos-complement; MSB is at lower physical address. 30-31 48-49 2 RXSLP2h: RXSLP2l RX power slope 2; unsigned fixed-point; MSB is at lower physical address. 32-33 50-51 2 RXOFF2h: RXOFF2l RX power offset 2; signed twos-complement; MSB is at lower physical address. 34-35 52-53 2 RXSLP3h: RXSLP3l RX power slope 3; unsigned fixed-point; MSB is at lower physical address. 36-37 54-55 2 RXOFF3h: RXOFF3l RX power offset 3; signed twos-complement; MSB is at lower physical address. 38-39 56-57 2 RXSLP4h: RXSLP4l RX power slope 4; unsigned fixed-point; MSB is at lower physical address. 3A-3B 58-59 2 RXOFF4h: RXOFF4l RX power offset 4; signed twos-complement; MSB is at lower physical address. 3C-3D 60-61 2 RXSLP5h: RXSLP5l RX power slope 5; unsigned fixed-point; MSB is at lower physical address. 3E-3F 62-63 2 RXOFF5h: RXOFF5l RX power offset 5; signed twos-complement; MSB is at lower physical address. 40-41 64-65 2 RXSLP6h: RXSLP6l RX power slope 6; unsigned fixed-point; MSB is at lower physical address. 42-43 66-67 2 RXOFF6h: RXOFF6l RX power offset 6; signed twos-complement; MSB is at lower physical address. 44-45 68-69 2 RXOFF7h: RXOFF7l RX power slope 7; signed twos-complement; MSB is at lower physical address. 46-47 70-71 2 RXSLP7h: RXSLP7l RX power slope 7; signed fixed-point; MSB is at lower physical address. Table 9. Internal Calibration Coefficient Memory Map – Part II August 2004 21 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 C/ ADC Result Registers Reading In the present revision of MIC3001, the ADC result registers should be read as 16 bit registers under internal calibration while under external calibration they should be read as 8 bit registers at the MSB address. For example, TX power should be read under internal calibration as 16 bits at address A2h: 66–67 and under external calibration as 8 bits at address A2h: 66h. RXPOT A programmable, non-volatile digitally controlled potentiometer is provided for adjusting the gain of the receive power measurement signal chain in the analog domain. Five bits in the RXPOT register are used to set and adjust the position of potentiometer. RXPOT functions as a programmable divider or attenuator. It is adjustable in steps from 1:1 (no divider action) down to 1/32 in steps of 1/32. If RXPOT is set to zero, the divider is bypassed completely. There will be no scaling of the input signal, and the resistor network will be disconnected from the VRX pin. At all other settings of RXPOT, there will be a 32k Ω (typical) load seen on VRX. Furthermore, the reference level for the APC circuit is selectable to accommodate electrical, i.e., current feedback, or optical feedback via a monitor photodiode. Finally, any one of seven different internal feedback resistors can be selected. This internal resistor can be used alone or in parallel with an external resistor. This wide range of adjustability (50:1) accommodates a wide range of photodiode current, i.e, wide range of transmitter output power. The APC operating point can be kept near the midscale value of the APC DAC, insuring maximum SNR, maximum effective resolution for digital diagnostics, and the widest possible DAC adjustment range for temperature compensation, etc. See Figure 5. The APCCAL bit in OEMCAL0 is used to turn the APC function on and off. It will be turned off in the MIC3001’s default state as shipped from the factory. When APC is on, the value in the selected APCSETx register is added to the signed value taken from the APC look-up table and loaded into the VBIAS DAC. When APC is off, the VBIAS DAC may be written directly via the VBIAS register, bypassing the lookup table entirely. This provides direct control of the laser diode bias during setup and calibration. In either case, the VBIAS DAC setting is reported in the APCDAC register. The APCCFG bits determine the DACs response to higher or lower numeric values. Figure 3. RXPOT Block Diagram Laser Diode Bias Control The MIC3001 can be configured to generate a constant bias current using electrical feedback, or regulate average transmitted optical power using a feedback signal from a monitor photodiode, see Figure 4. An operational amplifier is used to control laser bias current via the VBIAS output. The VBIAS pin can drive a maximum of ±10mA. An external bipolar transistor provides current gain. The polarity of the op amp’s output is programmable BIASREF in OEMCFG1 in order to accommodate either NPN or PNP transistors that drive common anode and common cathode laser, respectively. Additionally, the polarity of the feedback signal is programmable for use with either common-emitter or emitter-follower transistor circuits. Figure 4. MIC3001 APC and Modulation Control Block Diagram Figure 5. Programmable Feedback Resistor August 2004 22 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Laser Modulation Control As shown in Figure 4, a temperature-compensated DAC is provided to set and control the laser modulation current via an external laser driver circuit. MODREF in OEMCFG0 selects whether the VMOD DAC output swings up from ground or down from VDD. If the laser driver requires a voltage input to set the modulation current, the MIC3001’s VMOD output can drive it directly. If a current input is required, a fixed resistor can be used between the driver and the VMOD output. Several different configurations are possible as shown in Figure 7. When APC is on, i.e., the APCCAL bit in OEMCAL0 is set to 0, the value corresponding to the current temperature is taken from the MODLUT look-up table, added to MODSET, and loaded into the VMOD DAC. When APC is off, the value in VMOD is loaded directly into the VMOD DAC, bypassing the look-up table entirely. This provides for direct modulation control for setup and calibration. The MODREF bit determines the DACs response to higher or lower numeric values. Figure 7. VMOD Configured as Voltage Output with Gain Figure 6. Transmitter Configurations Supported by MIC3001 August 2004 23 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Power ON and Laser Start-Up When power is applied, the MIC3001 initializes its internal registers and state machine. This process takes tPOR, about 50ms. Following tPOR, analog-to-digital conversions begin, serial communication is possible, and the POR bit and data ready bits may be polled. The first set of analog data will be available tCONV after tPOR. MIC3001s are shipped from the factory with the output enable bit, OE, set to zero, off. The MIC3001’s power-up default state, therefore, is APC off, VBIAS, VMOD, and SHDN outputs disabled. VBIAS, VMOD, and SHDN will be floating (high impedance) and the laser diode, if connected, will be off. Once the device is incorporated into a transceiver and properly configured, the shutdown states of SHDN, VBIAS and VMOD will be determined by the state of the APC configuration and OE bits. Table 10, Table 11, and Table 12 illustrate the shutdown states of the various laser control outputs versus the control bits. Configuration Bits Shutdown State OE SPOL SHDN 0 Don’t Care Hi-Z 1 0 ≈GND 1 1 ≈VDD Table 10. Shutdown State of SHDN vs. Configuration Bits August 2004 Configuration Bits VBIAS Shutdown State OE INV BIASREF VBIAS 0 Don’t Care Don’t Care Hi-Z 1 Don’t Care 0 ≈GND 1 Don’t Care 1 ≈VDD Table 11. Shutdown State of VBIAS vs. Configuration Bits Configuration Bits VMOD Shutdown State OE MODREF VMOD 0 Don’t Care Hi-Z 1 0 ≈GND 1 1 ≈VDD Table 12. Shutdown State of VMOD vs. Configuration Bits In order to facilitate hot-plugging, the laser diode is not turned on until tINIT2 after power-on. Following tINIT2, and assuming TXDISABLE is not asserted, the DACs will be loaded with their initial values. Since tCONV is much less than tINIT2, the first set of analog data, including temperature, is available at tINIT2. Temperature compensation will be applied to the DAC values if enabled. APC will begin if OE is asserted. (If the output enable bit, OE, is not set, the VMOD, VBIAS, and SHDN outputs will float indefinitely.) Figure 8 shows the powerup timing of the MIC3001. If TXDISABLE is asserted at power-up, the VMOD and VBIAS outputs will stay in their shutdown states following MIC3001 initialization. A/D conversions will begin, but the laser will remain off. 24 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Figure 8. MIC3001 Power-On Timing (OE = 1) Fault Comparators In addition to detecting and reporting the events specified in SFF-8472, the MIC3001 also monitors five fault conditions: inadequate supply voltage, thermal diode faults, excessive bias current, excessive transmit power, and APC op-amp saturation. Comparators monitor these parameters in order to respond quickly to fault conditions that could indicate link failure or safety issues, see Figure 9. When a fault is detected, the laser is shut down and TXFAULT is asserted. Each fault source may be independently disabled using the FLTMSK register. FLTMSK is non-volatile, allowing faults to be masked only during calibration and testing or permanently. Figure 9. Fault Comparator Logic August 2004 Thermal diode faults are detected within the temperature measurement subsystem when an out-of-range signal is detected. A window comparator circuit monitors the voltage on the compensation capacitor to detect APC op-amp saturation (Figure 10). Op-amp saturation indicates that some fault has occurred in the control loop such as loss of feedback. The saturation detector is blanked for a time, tFLTTMR, following laser turn-on since the compensation voltage will essentially be zero at turn-on. The FLTTMR interval is programmable from 0.5ms to 127ms (typical) in increments of 0.5ms (fFLTTMR). Note that a saturation comparator cannot be relied upon to meet certain eyesafety standards that require 100ms response times. This is because the operation of a saturation detector is limited by the loop bandwidth, i.e., the choice of CCOMP. Even if the comparator itself was very fast, it would be subject to the limited slew-rate of the APC op-amp. Only the other fault comparator channels will meet TMAX Set ALARM0[7] Temperature low alarm TEMP < TMIN Set ALARM0[6] Voltage high alarm VIN > VMAX Set ALARM0[5] Voltage low alarm VIN < VMIN Set ALARM0[4] TX bias high alarm IBIAS > IBMAX Set ALARM0[3] TX bias low alarm IBIAS < IBMIN Set ALARM0[2] TX power high alarm TXOP > TXMAX Set ALARM0[1] TX power low alarm TXOP < TXMIN Set ALARM0[0] RX power high alarm RXOP > RXMAX Set ALARM1[7] RX power low alarm RXOP < RXMIN Set ALARM1[6] Temperature high warning TEMP > THIGH Set WARN0[7] Temperature low warning TEMP < TLOW Set WARN0[6] Voltage high warning VIN > VHIGH Set WARN0[5] Voltage low warning VIN < VLOW Set WARN0[4] TX bias high warning IBIAS > IBHIGH Set WARN0[3] TX bias low warning IBIAS < IBLOW Set WARN0[2] TX power high warning TXOP > TXHIGH Set WARN0[1] TX power low warning TXOP < TXLOW Set WARN0[0] RX power high warning RXOP > RXHIGH Set WARN1[7] RX power low warning RXOP < RXLOW Set WARN1[6] Temperature high alarm TEMP > TMAX Set ALARM0[7] Table 19. MIC3001 Events August 2004 31 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Figure 14. Control and Status I/O Logic System Timing The timing specifications for MIC3001 control and status I/O are given in the “Electrical Characteristics” section. Figure 15. Transmitter ON-OFF Timing Figure 16. Initialization Timing with TXDISABLE Asserted August 2004 32 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Figure 17. Initialization Timing with TXDISABLE Not Asserted Figure 18. Loss-of-Signal (LOS) Timing Figure 19. Transmit Fault Timing August 2004 33 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Figure 20. Successfully Clearing a Fault Condition Figure 21. Unsuccessful Attempt to Clear a Fault August 2004 34 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Warm Resets The MIC3001 can be reset to its power-on default state during operation by setting the reset bit in OEMCFG0. When this bit is set, TXFAULT and RXLOS will be deasserted, all registers will be restored to their normal power-on default values, and any A/D conversion in progress will be halted and the results discarded. The state of the MIC3001 following this operation is indistinguishable from a power-on reset. Power-On Hour Meter The Power-On Hour meter logs operating hours using an internal real-time clock and stores the result in NVRAM. The hour count is incremented at ten-hour intervals in the middle of each interval. The first increment therefore takes place five hours after power-on. Time is accumulated whenever the MIC3001 is powered. The hour meter’s timebase is accurate to 5% over all MIC3001 operating conditions. The counter is capable of storing counts of more than thirty years, but is ultimately limited by the write-cycle endurance of the non-volatile memory. This implies a range of at least twenty years. Actual results will depend on the operating conditions and write-cycle endurance of the part in question. Two registers, POHH and POHl, contain a 15-bit power-on hour measurement and an error flag, POHFLT. Great care has been taken to make the MIC3001’s hour meter immune to data corruption and to insure that valid data is maintained across power cycles. The hour meter employs multiple data copies and error correction codes to maintain data validity. This data is stored in the POHDATA registers. If POHFLT is set, however, the power-on hour meter data has been corrupted and should be ignored. It is recommended that a two-byte (or more) sequential read operation be performed on POHh and POHl to insure coherency between the two registers. These registers are accessible by the OEM using a valid OEM password. The only operation that should be performed on these registers is to clear the hour meters initial value, if necessary, at the time of product shipment. The hour meter result may be cleared by setting all eight POHDATA bytes to 00h. Power-On Hour Result Format High Byte, POHH Error Flag Low Byte, POHI Elapsed Time / 10 Hours, MSBs Elapsed Time / 10 Hours, LSBs MSB LSB Table 20. Power-On Hour Meter Result Format Test and Calibration Features Numerous features are included in the MIC3001 to facilitate development, testing, and diagnostics. These features are available via registers in the OEM area. As shown in Table 21, these features include: Function Description Control Register(s) Analog loop-back Provides analog visibility of op-amp and DAC outputs via the ADC OEMCFG0 Fault comparator disable control Disables the fault comparator OEMCAL0 Fault comparator spin-on-channel mode Selects a single fault comparator channel OEMCAL0 Fault comparator output read-back Allows host to read individual fault comparator outputs OEMRD RSOUT, /INT read-back Allows host to read the state of these pins OEMRD Inhibit EEPROM write cycles Speeds repetitive writes to registers backed up by NVRAM OEMCAL0 APC calibration mode Allows direct writes to MODDAC and APCDAC (temperature compensation not used) OEMCAL0 Continuity checking Forcing of RXLOS, TXFAULT, /INT OEMCAL0 Halt A/D Stops A/D conversions; ADC in one-shot mode OEMCAL1 ADC idle flag Indicates ADC status OEMCAL1 A/D one-shot mode Performs a single A/D conversion on the selected input channel OEMCAL1 A/D spin-on-channel mode Selects a single input channel OEMCAL1 Channel selection Selects ADC or fault comparator channel for spin-on-channel modes OEMCAL1 LUT index read-back Permits visibility of the LUT index calculated by the state-machine LUTINDX Manufacturer and device ID registers Facilitates presence detection and version control MFG_ID, DEV_ID Table 21. Test and Diagnostic Features August 2004 35 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Serial Port Operation The MIC3001 uses standard Write_Byte, Read_Byte, and Read_Word operations for communication with its host. It also supports Page_Write and Sequential_Read transactions. The Write_Byte operation involves sending the device’s slave address (with the R/W bit low to signal a write operation), followed by the address of the register to be operated upon and the data byte. The Read_Byte operation is a composite write and read operation: the host first sends the device’s slave address followed by the register address, as in a write operation. A new start bit must then be sent to the MIC3001, followed by a repeat of the slave address with the R/W bit (LSB) set to the high (read) state. The data to be read from the part may then be clocked out. A Read_Word is similar, but two successive data bytes are clocked out rather than one. These protocols are shown in Figure 22 to 25. The MIC3001 will respond to up to four sequential slave addresses depending on whether it is in OEM or User mode. A match between one of the MIC3001’s addresses and the address specified in the serial bit stream must be made to initiate communication. The MIC3001 responds to slave addresses A0h and A2h in User Mode; it also responds to A4h and A6h in OEM Mode (assuming I2CADR = Axh). Page Writes To increase the speed of multi-byte writes, the MIC3001 allows up to four consecutive bytes (one page) to be written before the internal write cycle begins. The entire nonvolatile memory array is organized into four-byte pages. Each page begins on a register address boundary where the last two bits of the address are 00b. Thus the page is composed of any four consecutive bytes having the addresses xxxxxx00b, xxxxxx01b, xxxxxx10b, and xxxxxx11b. The page write sequence begins just like a Write_Byte operation with the host sending the slave address, R/W bit low, register address, etc. After the first byte is sent the host should receive an acknowledge. Up to three more bytes can be sent in sequence. The MIC3001 will acknowledge each one and increment its internal address register in anticipation of the next byte. After the last byte is sent, the host issues a STOP. The MIC3001’s internal write process then begins. If more than four bytes are sent, the MIC3001’s internal address counter wraps around to the beginning of the four-byte page. To accelerate calibration and testing, NVRAM write cycles can be disabled completely by setting the WRINH bit in OEMCAL0. Writes to registers that do not have NVRAM backup will not incur write-cycle delays when writes are inhibited. Write operations on registers that exist only in NVRAM will still incur write cycle delays. Figure 22. Write Byte Protocol Figure 23. Read Byte Protocol Figure 24. Read_Word Protocol August 2004 36 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Figure 25. Four-Byte Page_White Protocol Acknowledge Polling The MIC3001’s non-volatile memory cannot be accessed during the internal write process. To allow for maximum speed bulk writes, the MIC3001 supports acknowledge polling. The MIC3001 will not acknowledge serial bus transactions while internal writes are in progress. The host may therefore monitor for the end of the write process by periodically checking for an acknowledgement. Write Protection and Data Security OEM Password A password is required to access the OEM areas of the MIC3001, specifically the non-volatile memory, look-up tables, and registers at serial addresses A4h and A6h. A four-byte field, OEMPWSET, at serial address A6h is used for setting the OEM password. The OEM password is set by writing OEMPWSET with the new value. The password comparison is performed following the write to the MSB of the OEMPW, address 7Bh at serial address A2h. Therefore, this byte must be written last! A fourbyte burst-write sequence to address 78h may be used as this will result in the MSB being written last. The new password will not take effect until after a power-on reset occurs or a warm reset is performed using the RST bit in OEMCFG0. This allows the new password to be verified before it takes effect. The corresponding four-byte field for password entry, OEMPW, is located at serial address A2h. This field is therefore always visible to the host system. OEMPW is compared to the four-byte OEMPWSET field at serial address A6h. If the two fields match, access is allowed to the OEM areas of the MIC3001 non-volatile memory at serial addresses A4h and A6h. If OEMPWSET is all zeroes, no password security will exist. The value in OEMPW will be ignored. This helps prevent a deliberately unsecured MIC3001 from being inadvertently locked. Once a valid password is entered, the MIC3001 OEM August 2004 areas will be accessible. The OEM areas may be resecured by writing an incorrect password value at OEMPW, e.g., all zeroes. In all cases OEMPW must be written LSB first through MSB last. The OEM areas will be inaccessible following the final write operation to OEMPW’s LSB. The OEMPW field is reset to all zeros at power on. Any values written to these locations will be readable by the host regardless of the locked/unlocked status of the device. If OEMPWSET is set to zero (00000000h), the MIC3001 will remain unlocked regardless of the contents of the OEMPW field. This is the factory default security setting. NOTE: A valid OEM password allows access to the OEM and user areas of the chip, i.e., the entire memory map, regardless of any user password that may be in place. Once the OEM areas are locked, the user password can provide access and write protection for the user areas. User Password A password is required to access the USER areas of the MIC3001, specifically the non-volatile memory at serial addresses A0h and A2h. A one-byte field, USRPWSET at serial address A2h is used for setting the USER password. USRPWSET is compared to the USRPW field at serial address A2h. If the two fields match, access is allowed to the USER areas of the MIC3001 non-volatile memory at serial addresses A0h and A2h. The USER password is set by writing USRPWSET with the new value. The new password will not take effect until after a power-on reset occurs or a warm reset is performed using the RST bit in OEMCFG0. This allows the new password to be verified before it takes effect. NOTE: A valid OEM password allows access to the OEM and user areas of the chip, i.e., the entire memory map, regardless of any user password that may be in place. Once the OEM areas are locked, the user password can provide access and write protection for the user areas. If a valid OEM password is in place, the user password will have no effect. 37 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Detailed Register Descriptions Note: Serial bus addresses shown assume that I2CADR = Axh. Alarm Threshold Registers Temperature High Alarm Threshold MSB (TMAXh) D[7] read/write Default Value D[6] read/write D[5] read/write D[4] D[3] read/write read/write 0000 0000b = 00h (0°C) Serial Address A2h = 1010001b Byte Address 00 = 00h D[2] read/write D[1] read/write D[0] read/write Each LSB represents one degree centigrade. This register is to be used in conjunction with TMAXl to yield a sixteen-bit temperature value. The value in this register is uncalibrated. The value in TMAXh is compared against TEMPh. Alarm bit Ax is set if TEMPh > TMAXh. Temperature High Alarm Threshold LSB (TMAXh) D[5] read/write Default Value D[4] read/write D[3] read/write D[2] D[1] read/write read/write 0000 0000b = 00h (0°C) Serial Address A2h = 1010001b Byte Address 01 = 01h D[0] read/write This register is to be used in conjunction with TMAXh to yield a sixteen-bit temperature value. The value in TMAXh is compared against TEMPh. Alarm bit Ax is set if TMAXh > TEMPh. Since TEMPl is always zero, it is recommended that this register always be programmed to zero. This register is provided for compliance with SFF-8472. It is not used by the MIC3001 when doing threshold comparisons and setting alarm or warning bits. Temperature Low Alarm Threshold MSB (TMINh) D[7] read/write Default Value D[6] read/write D[5] read/write D[4] D[3] read/write read/write 0000 0000b = 00h (0°C) Serial Address A2h = 1010001b Byte Address 02 = 02h D[2] read/write D[1] read/write D[0] read/write Each LSB represents one degree centigrade. This register is to be used in conjunction with TMINl to yield a sixteen-bit temperature value. The value in TMINh is compared against TEMPh. Alarm bit Ax is set if TEMPh < TMINh. Temperature Low Alarm Threshold LSB (TMINl) D[7] read/write Default Value D[6] read/write D[5] read/write D[4] D[3] read/write read/write 0000 0000b = 00h (0°C) Serial Address A2h = 1010001b Byte Address 03 = 03h D[2] read/write D[1] read/write D[0] read/write This register is to be used in conjunction with TMINh to yield a sixteen-bit temperature value. The value in TMINh is compared against TEMPh. Alarm bit Ax is set if TEMPh < TMINh. Since TEMPl is always zero, it is recommended that this register always be programmed to zero. This register is provided for compliance with SFF-8472. It is not used by the MIC3001 when doing threshold comparisons and setting alarm or warning bits. August 2004 38 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Voltage High Alarm Threshold MSB(VMAXh) D[7] read/write D[6] read/write D[5] read/write D[4] read/write D[3] read/write Default Value 0000 0000b = 00h (0V) Serial Address A2h = 1010001b Byte Address 08 = 08h D[2] read/write D[1] read/write D[0] read/write Each LSB represents 25.6mV. This register is to be used in conjunction with VMAXl to yield a sixteen-bit value. The value in TMINh is compared against VINh. Alarm bit Ax is set if VINh > VMAXh. Voltage High Alarm Threshold LSB(VMAXl) D[7] read/write Default Value D[6] read/write D[5] read/write D[4] D[3] read/write read/write 0000 0000b = 00h (0V) Serial Address A2h = 1010001b Byte Address 09 = 09h D[2] read/write D[1] read/write D[0] read/write Each LSB represents 100µV. This register is to be used in conjunction with VINh to yield a sixteen-bit value. The value in VMAXh is compared against VINh. Alarm bit Ax is set if VINh > VMAXh. Since VINl is always zero, it is recommended that this register always be programmed to zero. This register is provided for compliance with SFF-8472. It is not used by the MIC3001 when doing threshold comparisons and setting alarm or warning bits. Voltage Low Alarm Threshold MSB (VMINh) D[7] read/write Default Value D[6] read/write D[5] read/write D[4] D[3] read/write read/write 0000 0000b = 00h (0V) Serial Address A2h = 1010001b Byte Address 10 = 0Ah D[2] read/write D[1] read/write D[0] read/write Each LSB represents 25.6mV. This register is to be used in conjunction with VMINl to yield a sixteen-bit value. The value in this register is uncalibrated. The value in VMINh is compared against VINh. Alarm bit Ax is set if VINh IMAXh. Bias Current High Alarm Threshold LSB (IMAXl) D[7] read/write Default Value D[6] read/write D[5] read/write D[4] D[3] read/write read/write 0000 0000b = 00h (0mA) Serial Address A2h = 1010001b Byte Address 17 = 11h D[2] read/write D[1] read/write D[0] read/write Each LSB represents 2µA. This register is to be used in conjunction with IMAXh to yield a sixteen-bit value. The value in this register is uncalibrated. The value in IMAXh is compared against ILDh. Alarm bit Ax is set if ILDh > IMAXh. Since ILDl is always zero, it is recommended that this register always be programmed to zero. This register is provided for compliance with SFF8472. It is not used by the MIC3001 when doing threshold comparisons and setting alarm or warning bits. Bias Current Low Alarm Threshold MSB (IMINh) D[7] read/write Default Value D[6] read/write D[5] read/write D[4] D[3] read/write read/write 0000 0000b = 00h (0mA) Serial Address A2h = 1010001b Byte Address 18 = 12h D[2] read/write D[1] read/write D[0] read/write This register is to be used in conjunction with IMINl to yield a sixteen-bit value. The value in this register is uncalibrated. The value in IMINh is compared against ILDh. Alarm bit Ax is set if ILDh < IMINh. Bias Current Low Alarm Threshold LSB (IMINl) D[7] read/write Default Value D[6] read/write D[5] read/write D[4] D[3] read/write read/write 0000 0000b = 00h (0mA) Serial Address A2h = 1010001b Byte Address 19 = 13h D[2] read/write D[1] read/write D[0] read/write Each LSB represents 2µA. This register is to be used in conjunction with IMINh to yield a sixteen-bit value. The value in this register is uncalibrated. The value in IMINh is compared against ILDh. Alarm bit Ax is set if ILDh < IMINh. Since ILDl is always zero, it is recommended that this register always be programmed to zero. This register is provided for compliance with SFF8472. It is not used by the MIC3001 when doing threshold comparisons and setting alarm or warning bits. August 2004 40 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 TX Optical Power High Alarm MSB (TXMAXh) D[7] read/write Default Value D[6] read/write D[5] read/write D[4] D[3] read/write read/write 0000 0000b = 00h (0mW) Serial Address A2h = 1010001b Byte Address 24 = 18h D[2] read/write D[1] read/write D[0] read/write Each LSB represents 25.6µW. This register is to be used in conjunction with TXOPl to yield a sixteen-bit value. The values in TXOPh:TXOPl are in an unsigned binary format. The value in this register is uncalibrated. The value in TXMAXh is compared against TXOPh. Alarm bit Ax is set if TXOPh > TXMAXh. TX Optical Power High Alarm LSB (TXMAXl) D[7] read/write Default Value D[6] read/write D[5] read/write D[4] D[3] read/write read/write 0000 0000b = 00h (0mW) Serial Address A2h = 1010001b Byte Address 25 = 19h D[2] read/write D[1] read/write D[0] read/write Each LSB represents 0.1µW. This register is to be used in conjunction with TXMAXh to yield a sixteen-bit value. The values in TXOPh:TXOPl are in an unsigned binary format. The value in this register is uncalibrated. The value in TXMAXh is compared against TXOPh. Alarm bit Ax is set if TXOPh > TXMAXh. Since TXOPl is always zero, it is recommended that this register always be programmed to zero. This register is provided for compliance with SFF-8472. It is not used by the MIC3001 when doing threshold comparisons and setting alarm or warning bits. TX Optical Power Low Alarm MSB (TXMINh) D[7] read/write Default Value D[6] read/write D[5] read/write D[4] D[3] read/write read/write 0000 0000b = 00h (0mW) Serial Address A2h = 1010001b Byte Address 26 = 1Ah D[2] read/write D[1] read/write D[0] read/write Each LSB represents 25.6µW. This register is to be used in conjunction with TXMINl to yield a sixteen-bit value. The values in TXMINh:TMINl are in an unsigned binary format. The value in this register is uncalibrated. The value in TXMINh is compared against TXOPh. Alarm bit Ax is set if TXOPh < TXMINh. TX Optical Power Low Alarm LSB (TXMINl) D[7] read/write Default Value D[6] read/write D[5] read/write D[4] D[3] read/write read/write 0000 0000b = 00h (0mW) Serial Address A2h = 1010001b Byte Address 27 = 1Bh D[2] read/write D[1] read/write D[0] read/write Each LSB represents 0.1µW. This register is to be used in conjunction with TXMINh to yield a sixteen-bit value. The values in TXOPh:TXOPl are in an unsigned binary format. The value in this register is uncalibrated. The value in TXMINh is compared against TXOPh. Alarm bit Ax is set if TXOPh < TXMINh. Since TXOPl is always zero, it is recommended that this register always be programmed to zero. This register is provided for compliance with SFF-8472. It is not used by the MIC3001 when doing threshold comparisons and setting alarm or warning bits. August 2004 41 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 RX Optical Power High Alarm Threshold MSB (RXMAXh) D[7] read/write Default Value D[6] read/write D[5] read/write D[4] D[3] read/write read/write 0000 0000b = 00h (0mW) Serial Address A2h = 1010001b Byte Address 32 = 20h D[2] read/write D[1] read/write D[0] read/write Each LSB represents 25.6µW. This register is to be used in conjunction with RXMAXl to yield a sixteen-bit value. The value in this register is uncalibrated. The value in RXMAXh is compared against RXOPh. Alarm bit Ax is set if RXOPh > RXMAXh. RX Optical Power High Alarm Threshold LSB (RXMAXl) D[7] read/write Default Value D[6] read/write D[5] read/write D[4] D[3] read/write read/write 0000 0000b = 00h (0mW) Serial Address A2h = 1010001b Byte Address 33 = 21h D[2] read/write D[1] read/write D[0] read/write Each LSB represents 0.1µW. This register is to be used in conjunction with RXMAXh to yield a sixteen-bit value. The values in RXMAXh:RXMAXl are in an unsigned binary format. The value in this register is uncalibrated. The value in RXMAXh is compared against RXOPh. Alarm bit Ax is set if RXOPh > RXMAXh. Since RXOPl is always zero, it is recommended that this register always be programmed to zero. This register is provided for compliance with SFF-8472. It is not used by the MIC3001 when doing threshold comparisons and setting alarm or warning bits. RX Optical Power Low Alarm Threshold MSB (RMINh) D[7] read/write Default Value D[6] read/write D[5] read/write D[4] D[3] read/write read/write 0000 0000b = 00h (0mW) Serial Address A2h = 1010001b Byte Address 34 = 22h D[2] read/write D[1] read/write D[0] read/write Each LSB represents 25.6µW. This register is to be used in conjunction with RXMINl to yield a sixteen-bit value. The value in this register is uncalibrated. The value in RXMINh is compared against RXOPh. Alarm bit Ax is set if RXOPh < RXMINh. RX Optical Power Low Alarm Threshold LSB (RMINl) D[7] read/write Default Value D[6] read/write D[5] read/write D[4] D[3] read/write read/write 0000 0000b = 00h (0mW) Serial Address A2h = 1010001b Byte Address 35 = 23h D[2] read/write D[1] read/write D[0] read/write Each LSB represents 0.1µW. This register is to be used in conjunction with RXMINh to yield a sixteen-bit value. The values in RXMINh:RXMINl are in an unsigned binary format. The value in this register is uncalibrated. The value in RXMINh is compared against RXOPh. Alarm bit Ax is set if RXOPh < RXMINh. Since RXOPl is always zero, it is recommended that this register always be programmed to zero. This register is provided for compliance with SFF-8472. It is not used by the MIC3001 when doing threshold comparisons and setting alarm or warning bits. August 2004 42 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Warning Threshold Registers Temperature High Warning Threshold MSB (THIGHh) D[7] read/write Default Value D[6] read/write D[5] read/write D[4] D[3] read/write read/write 0000 0000b = 00h (0°C) Serial Address A2h = 1010001b Byte Address 04 = 04h D[2] read/write D[1] read/write D[0] read/write Each LSB represents one degree centigrade. This register is to be used in conjunction with THIGHl to yield a sixteen-bit temperature value. The value in this register is uncalibrated. The value in THIGHh is compared against TEMPh. Warning bit Wx is set if TEMPh > THIGHh. Temperature High Warning Threshold LSB (THIGHl) D[7] read/write Default Value D[6] read/write D[5] read/write D[4] D[3] read/write read/write 0000 0000b = 00h (0°C) Serial Address A2h = 1010001b Byte Address 05 = 05h D[2] read/write D[1] read/write D[0] read/write This register is to be used in conjunction with THIGHh to yield a sixteen-bit temperature value. The value in this register is uncalibrated. The value in THIGHh is compared against TEMPh. Warning bit Wx is set if THIGHh > TEMPh. Since TEMPl is always zero, it is recommended that this register always be programmed to zero. This register is provided for compliance with SFF-8472. It is not used by the MIC3001 when doing threshold comparisons and setting alarm or warning bits. Temperature Low Warning Threshold MSB (TLOWh) D[7] read/write Default Value D[6] read/write D[5] read/write D[4] D[3] read/write read/write 0000 0000b = 00h (0°C) Serial Address A2h = 1010001b Byte Address 06 = 06h D[2] read/write D[1] read/write D[0] read/write Each LSB represents one degree centigrade. This register is to be used in conjunction with TLOWl to yield a sixteen-bit temperature value. The value in this register is uncalibrated. The value in TLOWh is compared against TEMPh. Warning bit Wx is set if TEMPh < TLOWh. Temperature Low Warning Threshold LSB (TLOWl) D[7] read/write Default Value Serial Address D[6] read/write D[5] read/write D[4] D[3] read/write read/write 0000 0000b = 00h (0°C) D[2] read/write D[1] read/write D[0] read/write A2h = 1010001b Byte Address 07 = 07h This register is to be used in conjunction with TLOWh to yield a sixteen-bit temperature value. The value in this register is uncalibrated. The value in TLOWh is compared against TEMPh. Warning bit Wx is set if TEMPh < TLOWh. Since TEMPl is always zero, it is recommended that this register always be programmed to zero. This register is provided for compliance with SFF-8472. It is not used by the MIC3001 when doing threshold comparisons and setting alarm or warning bits. August 2004 43 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Voltage High Warning Threshold MSB (VHIGHh) D[7] read/write Default Value D[6] read/write D[5] read/write D[4] D[3] read/write read/write 0000 0000b = 00h (0V) Serial Address A2h = 1010001b Byte Address 12 = 0Ch D[2] read/write D[1] read/write D[0] read/write Each LSB represents 25.6mV. This register is to be used in conjunction with VHIGHl to yield a sixteen-bit value. The value in this register is uncalibrated. The value in VHIGHh is compared against VINh. Warning bit Wx is set if VINh > VHIGHh. Voltage High Warning Threshold LSB (VHIGHl) D[7] read/write Default Value D[6] read/write D[5] read/write D[4] D[3] read/write read/write 0000 0000b = 00h (0V) Serial Address A2h = 1010001b Byte Address 13 = 0Dh D[2] read/write D[1] read/write D[0] read/write Each LSB represents 100µV. This register is to be used in conjunction with VHIGHh to yield a sixteen-bit value. The value in VHIGHh is compared against VINh. Warning bit Wx is set if VINh > VHIGHh. Since VINl is always zero, it is recommended that this register always be programmed to zero. This register is provided for compliance with SFF-8472. It is not used by the MIC3001 when doing threshold comparisons and setting alarm or warning bits. Voltage Low Warning Threshold MSB (VLOWh) D[7] read/write Default Value D[6] read/write D[5] read/write D[4] D[3] read/write read/write 0000 0000b = 00h (0V) Serial Address A2h = 1010001b Byte Address 14 = 0Eh D[2] read/write D[1] read/write D[0] read/write Each LSB represents 25.6mV. This register is to be used in conjunction with VLOWl to yield a sixteen-bit value. The value in this register is uncalibrated. The value in VLOWh is compared against VINh. Warning bit Wx is set if VINh < VLOWhh. Voltage Low Warning Threshold LSB (VLOWl) D[7] read/write Default Value D[6] read/write D[5] read/write D[4] D[3] read/write read/write 0000 0000b = 00h (0V) Serial Address A2h = 1010001b Byte Address 15 = 0Fh D[2] read/write D[1] read/write D[0] read/write Each LSB represents 100µV. This register is to be used in conjunction with VLOWh to yield a sixteen-bit value. The value in VLOWh is compared against VINh. Warning bit Wx is set if VINh < VLOWh. Since VINl is always zero, it is recommended that this register always be programmed to zero. This register is provided for compliance with SFF-8472. It is not used by the MIC3001 when doing threshold comparisons and setting alarm or warning bits. August 2004 44 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Bias Current High Warning Threshold MSB (IHIGHh) D[7] read/write Default Value D[6] read/write D[5] read/write D[4] D[3] read/write read/write 0000 0000b = 00h (0mA) Serial Address A2h = 1010001b Byte Address 20 = 14h D[2] read/write D[1] read/write D[0] read/write This register is to be used in conjunction with IHIGHl to yield a sixteen-bit value. The value in this register is uncalibrated. The value in IHIGHh is compared against ILDh. Warning bit Wx is set if ILDh > IHIGHh. Bias Current High Warning Threshold LSB (IHIGHl) D[7] read/write Default Value D[6] read/write D[5] read/write D[4] D[3] read/write read/write 0000 0000b = 00h (0mA) Serial Address A2h = 1010001b Byte Address 21 = 15h D[2] read/write D[1] read/write D[0] read/write Each LSB represents 2µA. This register is to be used in conjunction with IHIGHh to yield a sixteen-bit value. The value in this register is uncalibrated. The value in IHIGHh is compared against ILDh. Warning bit Wx is set if ILDh > IHIGHh. Since ILDl is always zero, it is recommended that this register always be programmed to zero. This register is provided for compliance with SFF-8472. It is not used by the MIC3001 when doing threshold comparisons and setting alarm or warning bits. Bias Current Low Warning Threshold MSB (ILOWh) D[7] read/write Default Value D[6] read/write D[5] read/write D[4] D[3] read/write read/write 0000 0000b = 00h (0mA) Serial Address A2h = 1010001b Byte Address 22 = 16h D[2] read/write D[1] read/write D[0] read/write This register is to be used in conjunction with ILOWl to yield a sixteen-bit value. The value in this register is uncalibrated. The value in ILOWh is compared against ILDh. Warning bit Wx is set if ILDh < ILOWh. Bias Current Low Warning Threshold LSB (ILOWl) D[7] read/write Default Value D[6] read/write D[5] read/write D[4] D[3] read/write read/write 0000 0000b = 00h (0mA) Serial Address A2h = 1010001b Byte Address 23 = 17h D[2] read/write D[1] read/write D[0] read/write Each LSB represents 2µA. This register is to be used in conjunction with ILOWh to yield a sixteen-bit value. The value in this register is uncalibrated. The value in ILOWh is compared against ILDh. Warning bit Wx is set if ILDh < ILOWh. Since ILDl is always zero, it is recommended that this register always be programmed to zero. This register is provided for compliance with SFF-8472. It is not used by the MIC3001 when doing threshold comparisons and setting alarm or warning bits. August 2004 45 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 TX Optical Power High Warning MSB (TXHIGHh) D[7] read/write Default Value D[6] read/write D[5] read/write D[4] D[3] read/write read/write 0000 0000b = 00h (0mW) Serial Address A2h = 1010001b Byte Address 28 = 1Ch D[2] read/write D[1] read/write D[0] read/write Each LSB represents 25.6µW. This register is to be used in conjunction with TXHIGHl to yield a sixteen-bit value. The values in TXHIGHh:TXHIGHl are in an unsigned binary format. The value in this register is uncalibrated. The value in TXHIGHh is compared against TXOPh. Warning bit Wx is set if TXOPh > TXHIGHh. TX Optical Power High Warning LSB (TXHIGHl) D[7] read/write Default Value D[6] read/write D[5] read/write D[4] D[3] read/write read/write 0000 0000b = 00h (0mW) Serial Address A2h = 1010001b Byte Address 29 = 1Dh D[2] read/write D[1] read/write D[0] read/write Each LSB represents 0.1µW. This register is to be used in conjunction with TXHIGHh to yield a sixteen-bit value. The values in TXHIGHh:TXHIGHl are in an unsigned binary format. The value in this register is uncalibrated. The value in TXHIGHh is compared against TXOPh. Warning bit Wx is set if TXOPh > TXHIGHh. Since TXOPl is always zero, it is recommended that this register always be programmed to zero. This register is provided for compliance with SFF-8472. It is not used by the MIC3001 when doing threshold comparisons and setting alarm or warning b. TX Optical Power Low Warning MSB (TLOWh) D[7] read/write Default Value D[6] read/write D[5] read/write D[4] D[3] read/write read/write 0000 0000b = 00h (0mW) Serial Address A2h = 1010001b Byte Address 30 = 1Eh D[2] read/write D[1] read/write D[0] read/write Each LSB represents 25.6µW. This register is to be used in conjunction with TXLOWl to yield a sixteen-bit value. The values in TXLOWh:TLOWl are in an unsigned binary format. The value in this register is uncalibrated. The value in TXLOWh is compared against TXOPh. Warning bit Wx is set if TXOPh < TXLOWh. TX Optical Power Low Warning LSB (TLOWl) D[7] read/write Default Value D[6] read/write D[5] read/write D[4] D[3] read/write read/write 0000 0000b = 00h (0mW) Serial Address A2h = 1010001b Byte Address 31 = 1Fh D[2] read/write D[1] read/write D[0] read/write Each LSB represents 0.1µW. This register is to be used in conjunction with TXLOWh to yield a sixteen-bit value. The values in TXLOWh:TXLOWl are in an unsigned binary format. The value in this register is uncalibrated. The value in TXLOWh is compared against TXOPh. Warning bit Wx is set if TXOPh < TXLOWh. Since TXOPl is always zero, it is recommended that this register always be programmed to zero. This register is provided for compliance with SFF-8472. It is not used by the MIC3001 when doing threshold comparisons and setting alarm or warning bits. August 2004 46 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 RX Optical Power High Warning Threshold MSB (RXHIGHh) D[7] read/write Default Value D[6] read/write D[5] read/write D[4] D[3] read/write read/write 0000 0000b = 00h (0mW) Serial Address A2h = 1010001b Byte Address 36 = 24h D[2] read/write D[1] read/write D[0] read/write Each LSB represents 25.6µW. This register is to be used in conjunction with RXHIGHl to yield a sixteen-bit value. The value in this register is uncalibrated. The value in RXHIGHh is compared against RXOPh. Warning bit Wx is set if RXOPh > RXHIGHh. RX Optical Power High Warning Threshold LSB (RXHIGHl) D[7] read/write Default Value D[6] read/write D[5] read/write D[4] D[3] read/write read/write 0000 0000b = 00h (0mW) Serial Address A2h = 1010001b Byte Address 37 = 25h D[2] read/write D[1] read/write D[0] read/write Each LSB represents 0.1µW. This register is to be used in conjunction with RXHIGHh to yield a sixteen-bit value. The values in RXHIGHh:RXHIGHl are in an unsigned binary format. The value in this register is uncalibrated. The value in RXHIGHh is compared against RXOPh. Warning bit Wx is set if RXOPh > RXHIGHh. Since RXOPl is always zero, it is recommended that this register always be programmed to zero. This register is provided for compliance with SFF-8472. It is not used by the MIC3001 when doing threshold comparisons and setting alarm or warning bits. RX Optical Power Low Warning Threshold MSB (RXLOWh) D[7] read/write Default Value D[6] read/write D[5] read/write D[4] D[3] read/write read/write 0000 0000b = 00h (0mW) Serial Address A2h = 1010001b Byte Address 38 = 26h D[2] read/write D[1] read/write D[0] read/write Each LSB represents 25.6µW. This register is to be used in conjunction with RXLOWl to yield a sixteen-bit value. The value in this register is uncalibrated. The value in RXLOWh is compared against RXOPh. Warning bit Wx is set if RXOPh < RXLOWh. RX Optical Power Low Warning Threshold LSB (RXLOWl) D[7] read/write Default Value D[6] read/write D[5] read/write D[4] D[3] read/write read/write 0000 0000b = 00h (0mW) Serial Address A2h = 1010001b Byte Address 39 = 27h D[2] read/write D[1] read/write D[0] read/write Each LSB represents 0.1µW. This register is to be used in conjunction with RXLOWh to yield a sixteen-bit value. The values in RXLOWh:RXLOWl are in an unsigned binary format. The value in this register is uncalibrated. The value in RXLOWh is compared against RXOPh. Warning bit Wx is set if RXOPh < RXLOWh. Since RXOPl is always zero, it is recommended that this register always be programmed to zero. This register is provided for compliance with SFF-8472. It is not used by the MIC3001 when doing threshold comparisons and setting alarm or warning bits. August 2004 47 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Checksum (CHKSUM) Checksum of bytes 0 - 94 at serial address A2h D[7] read/write Default Value D[6] read/write D[5] read/write D[4] D[3] read/write read/write 0000 0000b = 00h (0°C) Serial Address A2h = 1010001b Byte Address 95 = 5Fh D[2] read/write D[1] read/write D[0] read/write This register is provided for compliance with SFF-8472. It is implemented as general-purpose non-volatile memory. Read/write access is possible whenever a valid OEM password has been entered. CHKSUM is read-only in USER mode. August 2004 48 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 ADC Result Registers Temperature Result MSB (TEMPh) D[7] read-only Default Value D[6] read-only D[5] read-only D[4] read-only Serial Address D[3] read-only 0000 0000b = 00h (0°C)(1) A2h = 1010001b Byte Address 96 = 60h D[2] read-only D[1] read-only D[0] read-only Each LSB represents one degree centigrade. This register is to be used in conjunction with TEMPl to yield a sixteen-bit temperature value. The value in this register is uncalibrated. The host should process the results using the scale factor and offset provided. See the External Calibration section. Temperature Result LSB (TEMPl) D[7] read-only Default Value D[6] read-only D[5] read-only D[4] D[3] read-only read-only 0000 0000b = 00h (0°C) Serial Address A2h = 1010001b Byte Address 97 = 61h D[2] read-only D[1] read-only D[0] read-only This register is to be used in conjunction with TEMPh to yield a sixteen-bit temperature value. The value in this register is uncalibrated. The host should process the results using the scale factor and offset provided. See the External Calibration section. In the MIC3001 this register will always return zero. This register is provided for compliance with SFF-8472. It is not used by the MIC3001 when doing threshold comparisons and setting alarm or warning bits. Voltage MSB (VINh) D[7] read-only Default Value D[6] read-only D[5] read-only D[4] read-only Serial Address D[3] read-only 0000 0000b = 00h (0V)(2) A2h = 1010001b Byte Address 98 = 62h D[2] read-only D[1] read-only D[0] read-only Each LSB represents 25.6mV. This register is to be used in conjunction with VINl to yield a sixteen-bit value. The values in VINh:VlNl are in an unsigned binary format. The value in this register is uncalibrated. The host should process the results using the scale factor and offset provided. See the External Calibration section. Voltage LSB (VINl) D[7] read-only Default Value D[6] read-only D[5] read-only D[4] D[3] read-only read-only 0000 0000b = 00h (0V) Serial Address A2h = 1010001b Byte Address 99 = 63h D[2] read-only D[1] read-only D[0] read-only Each LSB represents 100µV. This register is to be used in conjunction with VINh to yield a sixteen-bit value. The values in VINh:VINl are in an unsigned binary format. The value in this register is uncalibrated. The host should process the results using the scale factor and offset provided. See the External Calibration section. In the MIC3001, this register will always return zero. This register is provided for compliance with SFF-8472. It is not used by the MIC3001 when doing threshold comparisons and setting alarm or warning bits. Notes: 1. TEMPh will contain measured temperature data after the completion of one conversion. 2. VINh will contain measured data after one A/D conversion cycle. August 2004 49 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Laser Diode Bias Current MSB (ILDh) D[7] read-only Default Value D[6] read-only D[5] read-only D[4] read-only Serial Address D[3] read-only 0000 0000b = 00h (0mA)(3) A2h = 1010001b Byte Address 100 = 64h D[2] read-only D[1] read-only D[0] read-only This register is to be used in conjunction with ILDl to yield a sixteen-bit value. The values in ILDh:ILDl are in an unsigned binary format. The value in this register is uncalibrated. The host should process the results using the scale factor and offset provided. See the External Calibration sections. Laser Diode Bias Current LSB (ILDl) D[7] read-only Default Value D[6] read-only D[5] read-only D[4] D[3] read-only read-only 0000 0000b = 00h (0mA) Serial Address A2h = 1010001b Byte Address 101 = 65h D[2] read-only D[1] read-only D[0] read-only Each LSB represents 2µA. This register is to be used in conjunction with ILDh to yield a sixteen-bit value. The values in ILDh:ILDl are in an unsigned binary format. The value in this register is uncalibrated. The host should process the results using the scale factor and offset provided. See the External Calibration section. In the MIC3001, this register will always return zero. This register is provided for compliance with SFF-8472. It is not used by the MIC3001 when doing threshold comparisons and setting alarm or warning bits. Transmitted Optical Power MSB (TXOPh)(4) D[7] read-only Default Value D[6] read-only D[5] read-only D[4] read-only Serial Address D[3] read-only 0000 0000b = 00h (0mW)(5) A2h = 1010001b Byte Address 102 = 66h D[2] read-only D[1] read-only D[0] read-only Each LSB represents 25.6µW. This register is to be used in conjunction with TXOPl to yield a sixteen-bit value. The values in TXOPh:TXOPl are in an unsigned binary format. The value in this register is uncalibrated. The host should process the results using the scale factor and offset provided. See the External Calibration section. Transmitted Optical Power LSB (TXOPl) D[7] read-only Default Value D[6] read-only D[5] read-only D[4] D[3] read-only read-only 0000 0000b = 00h (0mW) Serial Address A2h = 1010001b Byte Address 103 = 67h D[2] read-only D[1] read-only D[0] read-only Each LSB represents 0.1µW. This register is to be used in conjunction with TXOPh to yield a sixteen-bit value. The values in TXOPh:TXOPl are in an unsigned binary format. The value in this register is uncalibrated. The host should process the results using the scale factor and offset provided. See the External Calibration section. In the MIC3001, this register will always return zero. This register is provided for compliance with SFF-8472. It is not used by the MIC3001 when doing threshold comparisons and setting alarm or warning bitsection. Notes: 3. ILDh will contain measured data after one A/D conversion cycle. 4. The scale factor corresponding to the sense resistor used must be set in the configuration register. 5. TXOPh will contain measured data after one A/D conversion cycle. August 2004 50 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Received Optical Power MSB (RXOPh) D[7] read-only Default Value D[6] read-only D[5] read-only D[4] read-only Serial Address D[3] read-only 0000 0000b = 00h (0mW)(6) A2h = 1010001b Byte Address 104 = 68h D[2] read-only D[1] read-only D[0] read-only Each LSB represents 25.6µW. This register is to be used in conjunction with RXOPl to yield a sixteen-bit value. The values in RXOPh:RXOPl are in an unsigned binary format. The value in this register is uncalibrated. The host should process the results using the scale factor and offset provided. See the External Calibration section. Received Optical Power LSB (RXOPl) D[7] read-only Default Value D[6] read-only D[5] read-only D[4] read-only Serial Address D[3] read-only 0000 0000b = 00h (0mW)(6) A2h = 1010001b Byte Address 105 = 69h D[2] read-only D[1] read-only D[0] read-only Each LSB represents 0.1µW. This register is to be used in conjunction with RXOPh to yield a sixteen-bit value. The values in RXOPh:RXOPl are in an unsigned binary format. The value in this register is uncalibrated. The host should process the results using the coefficients provided. See the External Calibration section. This register is provided for compliance with SFF-8472. It is not used by the MIC3001 when doing threshold comparisons and setting alarm or warning bits. Control and Status (CNTRL) D[7] TXDIS read-only Default Value D[6] STXDIS read/write D[5] reserved D[4] RSEL read/write D[3] SRSEL read/write D[2] XFLT read-only 0000 0000b = 00h Serial Address A2h = 1010001b Byte Address 110 = 6Eh Bit(s) D[1] LOS read-only D[0] POR read-only Function Operation Reflects the state of the TXDISABLE pin 1 = disabled, 0 = enabled, read only. Soft transmit disable 1 = disabled; 0 = enabled. Reserved Reserved - always write as zero. D[7] TXDIS D[6] STXDIS D[5] D[5] D[4] RSEL Reflects the state of the RSEL pin 1 = high; 0 = low. D[3] SREL Soft rate select 1 = high (2Gbps); 0 = low (1Gbps). D[2] TXFLT Reflects the state of the TXFAULT pin 1 = high (fault); 0 = low (no fault). D[1] LOS Loss of signal. Reflects the state of the LOS pin 1 = high (loss of signal); 0 = low (no loss of signal). D[0] POR MIC3001 power-on status 0 = POR complete, analog data ready; 1 = POR in progress. Notes: 6. RXOPh will contain measured data after one A/D conversion cycle. August 2004 51 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Alarm Flags Alarm Register 0 (ALARM0) D[7] A7 read-only Default Value D[6] A6 read-only D[5] A5 read-only D[4] D[3] D[2] A4 A3 A2 read-only read-only read-only 0000 0000b = 00h (no events pending) Serial Address A2h = 1010001b Byte Address 112 = 70h D[1] A1 read-only D[0] A1 read-only The power-up default value is 00h. Following the first A/D conversion, however, any of the bits may be set depending on the results. Bit(s) Function Operation D[7] A7 High temperature alarm, TEMPh > TMAXh. 1 = condition exists, 0 = normal/OK. D[6] A6 Low temperature alarm, TEMPh < TMINh. 1 = condition exists, 0 = normal/OK. D[5] A5 High voltage alarm, VINh > VMAXh. 1 = condition exists, 0 = normal/OK. D[4] A4 Low voltage alarm, VINh < VMINh. 1 = condition exists, 0 = normal/OK. D[3] A3 High laser diode bias alarm, IBIASh > IMAXh. 1 = condition exists, 0 = normal/OK. D[2] A2 Low laser diode bias alarm, IBIASh < IMINh. 1 = condition exists, 0 = normal/OK. D[1] A1 High transmit optical power alarm, TXOPh > TXMAXh. 1 = condition exists, 0 = normal/OK. D[0] A0 Low transmit optical power alarm, TXOPh < TXMINh. 1 = condition exists, 0 = normal/OK. Alarm Register 1 (ALARM1) D[7] A15 read-only Default Value D[6] A14 read-only D[5] reserved D[4] reserved D[3] reserved D[2] reserved D[1] reserved D[0] reserved 0000 0000b = 00h (no events pending) Serial Address A2h = 1010001b Byte Address 113 = 71h The power-up default value is 00h. Following the first A/D conversion, however, any of the bits may be set depending on the results. Function Operation D[7] Bit(s) A15 High received power (overload) alarm, RXOPh > RXMAXh. 1 = condition exists, 0 = normal/OK. D[6] A14 Low received power (LOS) alarm, RXOPh < RXMINh. 1 = condition exists, 0 = normal/OK. Reserved Reserved - always write as zero. D[5:0] August 2004 52 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Warning Flags Warning Register 0 (WARN0) D[7] W7 read-only Default Value D[6] W6 read-only D[5] W5 read-only D[4] D[3] D[2] W4 W3 W2 read-only read-only read-only 0000 0000b = 00h (no events pending) Serial Address A2h = 1010001b Byte Address 116 = 74h D[1] W1 read-only D[0] W1 read-only The power-up default value is 00h. Following the first A/D conversion, however, any of the bits may be set depending on the results. Bit(s) Function Operation D[7] W7 High temperature warning, TEMPh > THIGHh. 1 = condition exists, 0 = normal/OK. D[6] W6 Low temperature warning, TEMPh < TLOWh. 1 = condition exists, 0 = normal/OK. D[5] W5 High voltage warning, VINh > VHIGHh. 1 = condition exists, 0 = normal/OK. D[4] W4 Low voltage warning, VINh < VLOWh. 1 = condition exists, 0 = normal/OK. D[3] W3 High laser diode bias warning, IBIASh > IHIGHh. 1 = condition exists, 0 = normal/OK. D[2] W2 Low laser diode bias warning, IBIASh < ILOWh. 1 = condition exists, 0 = normal/OK. D[1] W1 High transmit optical power warning, TXOPh > TXHIGHh. 1 = condition exists, 0 = normal/OK. D[0] W0 Low transmit optical power warning, TXOPh < TXLOWh. 1 = condition exists, 0 = normal/OK. Warning Register 1 (WARN1) D[7] W15 read-only Default Value D[6] W14 read-only D[5] read-only D[4] D[3] D[2] Serial Address read-only read-only read-only 0000 0000b = 00h (no events pending) A2h = 1010001b Byte Address 117 = 75h D[1] D[0] read-only read-only The power-up default value is 00h. Following the first A/D conversion, however, any of the bits may be set depending on the results. Function Operation D[7] Bit(s) W15 Received power high warning, RXOPh > RXHIGHh. 1 = condition exists, 0 = normal/OK. D[6] W14 Received power low warning, RXOPh < RXMINh. 1 = condition exists, 0 = normal/OK. Reserved Reserved - always write as zero. D[5:0] August 2004 53 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 OEM Password Entry (OEMPW) D[7] read/write Default Value D[6] read/write D[5] read/write D[4] D[3] D[2] read/write read/write read/write 0000 0000b = 00h (reset to zero at power-on) Serial Address A2h = 1010001b Byte Address 120 – 123 = 78h - 7Bh D[1] read/write D[0] read/write (MSB is 7Bh) This four-byte field is for entry of the password required to access the OEM area of the MIC3001’s memory and registers. A valid OEM password will also permit access to the user areas of memory. The byte at address 123 (7Bh) is the most significant byte. This field is compared to the four-byte OEMPWSET field at serial address A6h, bytes 12 to 15. If the two fields match, access is allowed to the OEM areas of the MIC3001 non-volatile memory at serial addresses A4h and A6h. The OEM password is set by writing the new value into OEMPWSET. The password comparison is performed following the write to the MSB, address 7Bh. This byte must be written last! A four-byte burst-write sequence to address 78h may be used as this will result in the MSB being written last. The new password will not take effect until after a power-on reset occurs or a warm reset is performed using the RST bit in OEMCFG0. This allows the new password to be verified before it takes effect. This field is reset to all zeros at power on. Any values written to these locations will be readable by the host regardless of the locked/unlocked status of the device. If OEMPWSET is set to zero (00000000h), the MIC3001 will remain unlocked regardless of the contents of the OEMPW field. This is the factory default security setting. Byte Weight 3 OEM Password Entry, Most Significant Byte (Address = 7Bh) 2 OEM Password Entry, 2nd Most Significant Byte (Address = 7Ah) 1 OEM Password Entry, 2nd Least Significant Byte (Address = 79h) 0 OEM Password Entry, Least Significant Byte (Address = 78h) USER Password Setting (USRPWSET) D[7] read/write Default Value D[6] read/write D[5] read/write D[4] D[3] read/write read/write 0000 0000b = 00h Serial Address A2h = 1010001b Byte Address 250 = FAh D[2] read/write D[1] read/write D[0] read/write This register is for setting the password required to access the USER area of the MIC3001’s memory and registers. This field is compared to the USRPW field at serial address A2h, byte 251. If the two fields match, access is allowed to the USER areas of the MIC3001 non-volatile memory at serial addresses A0h and A2h. If a valid USER password has not been entered, writes to the serial ID fields, USRCTRL, and the user scratchpad areas of A0h and A2h will not be allowed, and USRPWSET will be unreadable (returns all zeroes). A USER password is set by writing the new value into USRPWSET. The new password will not take effect until after a power-on reset occurs or a warm reset is performed using the RST bit in OEMCFG0. This allows the new password to be verified before it takes effect. This register is non-volatile and will be maintained through power and reset cycles. A valid USER or OEM password is required for access to this register. Otherwise, this register will read as 00h. Note: a valid OEM password overrides the USER password setting. If a valid OEM password is currently in place, the user password will have no effect. August 2004 54 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 USER Password (USRPW) D[7] read/write Default Value D[6] read/write D[5] read/write D[4] D[3] read/write read/write 0000 0000b = 00h Serial Address A2h = 1010001b Byte Address 251 = FBh D[2] read/write D[1] read/write D[0] read/write USER passwords are entered in this field. This field is compared to the USRPWSET field at serial address A2h, byte 250. If the two fields match, access is allowed to the USER areas of the MIC3001 non-volatile memory at serial addresses A0h and A2h. If a valid USER password has not been entered, writes to the serial ID fields and user scratchpad areas of A0h and A2h will not be allowed and USRPWSET will be unreadable (returns all zeroes). Power-On Hours MSB (POHh) D[7] read/write Default Value D[6] read/write D[5] read/write D[4] D[3] read/write read/write 0000 0000b = 00h Serial Address A2h = 1010001b Byte Address 252 = FCh D[2] read/write D[1] read/write D[0] read/write The lower seven bits of this register contain the most-significant bits of the 15-bit power-on hours measurement. POHFLT is an error flag. The value in this register should be combined with the Power-on Hours, Low Byte, POHl, to yield the complete result. If POHFLT is set, the power-on hour meter data has been corrupted and should be ignored. It is recommended that a two-byte (or more) sequential read operation be performed on POHh and POHl to insure coherency between the two registers. This register is non-volatile and will be maintained through power and reset cycle. Bit(s) Function Operation D[7] Power-on hours fault flag 1 = fault; 0 = no fault. D[6:0] Power-on hours, high byte Non-volatile. Power-On Hours LSB (POHl) D[7] D[6] read/write read/write POH Fault Flag (POHFLT) Default Value D[5] read/write D[4] read/write D[3] read/write D[2] read/write D[1] read/write D[0] read/write 0000 0000b = 00h Serial Address A2h = 1010001b Byte Address 253 = FDh This register contains the least-significant eight bits of the 15-bit power-on hours measurement. The value in this register should be combined with the Power-on Hours, High Byte, POHh, to yield the complete result. If POHFLT is set, the power-on hour meter data has been corrupted and should be ignored. It is recommended that a two-byte (or more) sequential read operation be performed on POHh and POHl to insure coherency between the two registers. This register is non-volatile and will be maintained through power and reset cycles. August 2004 55 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Data Ready Flags (DATARDY) D[7] TRDY read/write Default Value D[6] VRDY read/write D[5] IRDY read/write D[4] D[3] TXRDY RXDY read/write read/write 0000 0000b = 00h Serial Address A2h = 1010001b Byte Address 254 = FEh D[2] reserved D[1] reserved D[0] reserved When the A/D conversion for a given parameter is completed and the results available to the host, the corresponding data ready flag will be set. The flag will be cleared when the host reads the corresponding result register. Bit(s) Function Operation D[7] TRDY Temperature data ready flag 0 = old data; 1 = new data ready D[6] VRDY Voltage data ready flag 0 = old data; 1 = new data ready D[5] IRDY Bias current data ready flag 0 = old data; 1 = new data ready D[4] TXRDY Transmit power data ready flag 0 = old data; 1 = new data ready D[3] RXRDY Receive power data ready flag 0 = old data; 1 = new data ready Reserved Reserved D[2:0] USER Control Register (USRCTL) D[7] D[6] PORM read/write read/write Default Value D[5] PORS read/write D[4] D[3] IE APCSEL read/write read/write 0010 0000b = 20h Serial Address A2h = 1010001b Byte Address 255 = FFh D[2] read/write D[1] read/write D[0] read/write This register provides for control of the nominal APC setpoint and management of interrupts by the end-user. APCSEL[1:0] select which of the APC setpoint registers, APCSET0, APCSET1, or APCSET2 are used as the nominal automatic power control setpoint. IE must be set for any interrupts to occur. If PORM is set, the power-on event will generate an interrupt and warm resets using RST will not generate a POR interrupt. When a power-on interrupt occurs, assuming PORM=1, PORS will be set. PORS will be cleared and the interrupt output de-asserted when USRCTL is read by the host. If IE is set while /INT is asserted, /INT will be de-asserted. The host must still clear the various status flags by reading them. If PORM is set following the setting of PORS, PORS will remain set, and /INT will not be de-asserted, until USRCTL is read by the host. PORM, IE, and APCSEL are non-volatile and will be maintained through power and reset cycles. A valid USER password is required for access to this register. Bit D[7] Function Operation Reserved Always write as zero; reads undefined. D[6] PORM Power-on interrupt mask 1 = POR interrupts enabled; 0 = disabled; read/write; non-volatile. D[5] PORS Power-on interrupt flag 1 = POR interrupt occurred; 0 = no POR interrupt; read-only. D[4] IE Global interrupt enable 1 = enabled; 0 = disabled; read/write; non-volatile. D[3] APCSEL Selects APC setpoint register 00 = APCSET0, 01 = APCSET1, 10 = APCSET2; 11 = reserved; read/write; non-volatile. Reserved Reserved D[2:0] August 2004 56 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 OEM Configuration Register 0 (OEMCFG0) D[7] RST write only Default Value D[6] ZONE read/write D[5] DFLT read only D[4] D[3] OE MODREF reserved reserved 0000 0000b = 00h Serial Address A6h = 1010011b Byte Address 00 = 00h D[2] VAUX[2] read/write D[1] VAUX[1] read/write D[0] VAUX[0] read/write A write to OEMCFG0 will result in any A/D conversion in progress being aborted and the result discarded. The A/D will begin a new conversion sequence once the write operation is complete. All bits in OEMCFG0 are non-volatile except DFLT and RST. A valid OEM password is required for access to this register. Bit(s) Function Operation D[7] RST 0 = no action; 1 = reset; write-only. D[6] ZONE Selects temperature zone. 0 = internal; 1 = external; non-volatile. D[5] DFLT Diode fault flag. 1 = diode fault; 0 = OK. D[4] OE Output enable for SHDN, VMOD, and VBIAS. 1 = enabled; 0 = hi-Z; non-volatile. D[3] MODREF Selects whether VMOD is referenced to ground or VDD. 1 = VDD; 0 = GND; non-volatile. D[2:0] VAUX[2:0] Selects the voltage reported in VINh:VINl. 000 = VIN; 001 = VDDA; 010 = VBIAS; 011 = VMOD; 100 = APCDAC; 101 = MODDAC; 110 = FLTDAC; non-volatile OEM Configuration Register 1 (OEMCFG1) D[7] INV read/write Default Value D[6] GAIN read/write D[5] BIASREF read/write D[4] D[3] RFB[2] RFB[1] read/write read/write 0000 0000b = 00h Serial Address A6h = 1010011b Byte Address 1 = 01h D[2] RFB[0] read/write D[1] SRCE read/write D[0] SPOL read/write A write to OEMCFG1 will result in any A/D conversion in progress being aborted and the result discarded. The A/D will begin a new conversion sequence once the write operation is complete. All bits in OEMCFG1 are non-volatile and will be maintained through power and reset cycles. A valid OEM password is required for access to this register. August 2004 57 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Bit(s) D[7] INV D[6] GAIN Function Operation Inverts the APC op-amp inputs. When set to “0” the BIAS DAC output is connected to the “+”input and FB is connected to the “–” input of the op amp. Set to “0” to use the ADC feedback loop. 0 = emitter follower (no inversion); Sets the feedback voltage range by changing the APCDAC output swing; 0-VREF for optical feedback, 0-VREF/4 for electrical feedback. 1 = VREF/4 full scale; 1 = common emitter (inverted); read/write; non-volatile. 0 = VREF full scale; read/write; non-volatile. D[5] BIASREF Selects whether FB and VMPD are referenced to ground or VDD and selects feedback resistor termination voltage (VDDA or GNDA). 1 = VDD; 0 = GND; read/write; non-volatile. D[4:2] RFB[2:0] Selects internal feedback resistance. (Resistors will be terminated to VDDA or GNDA according to BIASREF.) 000 = ∞; 001 = 800Ω, 010 = 1.6kΩ, 011 = 3.2kΩ, 100 = 6.4kΩ, 101 = 12.8kΩ, 110 = 25.6kΩ, 111 = 51.2kΩ; read/write; non-volatile. D[1] SRCE VBIAS source vs. sink drive. 1 = source (NPN), 0 = sink (PNP); read/write; non-volatile. D[0] SPOL Polarity of shutdown output, SHDN, when active. 1 = high; 0 = low; read/write; non-volatile. OEM Configuration Register 2 (OEMCFG2) D[7] I2CADR[3] read/write D[6] I2CADR[2] read/write D[5] I2CADR[1] read/write Default Value D[4] D[3] D[2] I2CADR[0] LUTOFF LUTOFF read/write read/write read/write 1010 xxxxb = xxh (slave address = 1010xxxb) Serial Address A6h = 1010011b Byte Address 2 = 02h D[1] LUTOFF read/write D[0] LUTOFF read/write CAUTION: Changes to I2CADR take effect immediately! Any accesses following a write to I2CADR must be to the newly programmed serial bus address. A valid OEM password is required for access to this register. This register is non-volatile and will be maintained through power and reset cycles. Bit(s) Function Operation D[7:4] I2CADR[3:0] Upper four MSBs of the serial bus slave address; writes take effect immediately. Read/write; non-volatile. D[3:0] LUTOFF LUT offset. LUTOFF is added to the result of the digital temperature sensor to derive the table index; writes take effect after reset. Read/write; non-volatile. August 2004 58 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 APC Setpoint 0 (APCSET0) Automatic power control setpoint (unsigned binary) used when APCSEL[1:0] = 00 D[7] read/write D[6] read/write D[5] read/write Default Value D[4] D[3] read/write read/write 0000 0000b = 00h Serial Address A6h = 1010011b Byte Address 3 = 03h D[2] read/write D[1] read/write D[0] read/write When A.P.C. is on, i.e., the APCCAL bit in OEMCAL0 is set, the value in APCSETx is added to the signed value taken from the A.P.C. look-up table and loaded into the VBIAS DAC. When A.P.C. is off, the value in APCSET is loaded directly into the VBIAS DAC, bypassing the look-up table entirely. In either case, the VBIAS DAC setting is reported in the VBIAS register. The APCCFG bits determine the DAC’s response to higher or lower numeric values. A valid OEM password is required for access to this register. This register is non-volatile and will be maintained through power and reset cycles. APC Setpoint 1 (APCSET1) Automatic power control setpoint (unsigned binary) used when APCSEL[1:0] = 01 D[7] read/write D[6] read/write D[5] read/write Default Value D[4] D[3] read/write read/write 0000 0000b = 00h Serial Address A6h = 1010011b Byte Address 4 = 04h D[2] read/write D[1] read/write D[0] read/write When A.P.C. is on, i.e., the APCCAL bit in OEMCAL0 is set, the value in APCSETx is added to the signed value taken from the A.P.C. look-up table and loaded into the VBIAS DAC. When A.P.C. is off, the value in APCSET is loaded directly into the VBIAS DAC, bypassing the look-up table entirely. In either case, the VBIAS DAC setting is reported in the VBIAS register. The APCCFG bits determine the DAC’s response to higher or lower numeric values. A valid OEM password is required for access to this register. This register is non-volatile and will be maintained through power and reset cycles. APC Setpoint 2 (APCSET2) Automatic power control setpoint (unsigned binary) used when APCSEL[1:0] = 10 D[7] read/write D[6] read/write D[5] read/write Default Value D[4] D[3] read/write read/write 0000 0000b = 00h Serial Address A6h = 1010011b Byte Address 5 = 05h D[2] read/write D[1] read/write D[0] read/write When A.P.C. is on, i.e., the APCCAL bit in OEMCAL0 is set, the value in APCSETx is added to the signed value taken from the A.P.C. look-up table and loaded into the VBIAS DAC. When A.P.C. is off, the value in APCSET is loaded directly into the VBIAS DAC, bypassing the look-up table entirely. In either case, the VBIAS DAC setting is reported in the VBIAS register. The APCCFG bits determine the DAC’s response to higher or lower numeric values. This register is non-volatile and will be maintained through power and reset cycles. A valid OEM password is required for access to this register. Modulation DAC Setting (MODSET) Nominal VMOD setpoint D[7] read/write D[6] read/write D[5] read/write Default Value D[4] D[3] read/write read/write 0000 0000b = 00h Serial Address A6h = 1010011b Byte Address 6 = 06h D[2] read/write D[1] read/write D[0] read/write When A.P.C. is on, the value corresponding to the current temperature is taken from the MODLUT look-up table, added to MODSET and loaded into the VMOD DAC. This register is non-volatile and will be maintained through power and reset cycles. A valid OEM password is required for access to this register. August 2004 59 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 IBIAS Fault Threshold (IBFLT) Bias current fault threshold D[7] read/write D[6] read/write D[5] read/write Default Value D[4] D[3] read/write read/write 0000 0000b = 00h Serial Address A6h = 1010011b Byte Address 7 = 07h D[2] read/write D[1] read/write D[0] read/write A valid OEM password is required for access to this register. This register is non-volatile and will be maintained through power and reset cycles. A fault is generated if the bias current is higher than IBFLT value set in this register. Transmit Power Fault Threshold (TXFLT) D[7] read/write D[6] read/write D[5] read/write Default Value D[4] D[3] read/write read/write 0000 0000b = 00h Serial Address A6h = 1010011b Byte Address 8 = 08h D[2] read/write D[1] read/write D[0] read/write A valid OEM password is required for access to this register. This register is non-volatile and will be maintained through power and reset cycles. A fault is generated if the Transmit power is higher than TXFLT value set in this register. Loss-Of-Signal Threshold (LOSFLT) D[7] read/write D[6] read/write D[5] read/write Default Value D[4] D[3] read/write read/write 0000 0000b = 00h Serial Address A6h = 1010011b Byte Address 9 = 09h D[2] read/write D[1] read/write D[0] read/write A valid OEM password is required for access to this register. This register is non-volatile and will be maintained through power and reset cycles. A fault is generated if the received power is lower than LOSFLT value set in this register. Byte Function Operation D[7:4] Receive loss-of-signal threshold Read/write; non-volatile. August 2004 60 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Fault Suppression Timer (FLTTMR) Fault suppression interval in increments of 0.5ms D[7] read/write D[6] read/write D[5] read/write Default Value D[4] D[3] read/write read/write 0000 0000b = 00h Serial Address A6h = 1010011b Byte Address 10 = 0Ah D[2] read/write D[1] read/write D[0] read/write Saturation faults are suppressed for a time, tFLTTMR, following laser turn-on. This avoids nuisance tripping while the APC loop starts up. The length of this interval is (FLTTMR∞0.5ms), typical. A value of zero will result in no fault suppression. A valid OEM password is required for access to this register. This register is non-volatile and will be maintained through power and reset cycles. Fault Mask (FLTMSK) D[7] OEMIM read/write Default Value D[6] POHE read/write D[5] reserved D[4] reserved D[3] SATMSK read/write D[2] TXMSK read/write D[1] IAMSK read/write D[0] DFMSK read/write 0000 0000b = 00h Serial Address A6h = 1010011b Byte Address 11 = 0Bh A valid OEM password is required for access to this register. This register is non-volatile and will be maintained through power and reset cycles. Bit Function Operation D[7] OEMIM OEM interrupt mask bit 1 = masked; 0 = enabled; Read/write; non-volatile. D[6] POHE OEM Power-on Hour Meter enable bit 1 = enabled; 0 = disabled; Read/write; non-volatile. D[5:4] D[5:4] Reserved Always write as zero; reads undefined. D[3] SATMSK APC saturation fault mask bit 1 = masked; 0 = enabled; Read/write; non-volatile. D[2] TXMSK High TX optical power fault mask bit 1 = masked; 0 = enabled; Read/write; non-volatile. D[1] IAMSK Bias current high alarm mask bit 1 = masked; 0 = enabled; Read/write; non-volatile. D[0] DFMSK Diode fault mask bit 1 = masked; 0 = enabled; Read/write; non-volatile. OEM Password Setting (OEMPWSET) D[7] read/write D[6] read/write D[5] read/write Default Value D[4] D[3] read/write read/write 0000 0000b = 00h Serial Address A6h = 1010011b Byte Address 12 - 15 = 0Fh - 0Fh; 0Ch = MSB D[2] read/write D[1] read/write D[0] read/write This four-byte field is the password required for access to the OEM area of the MIC3001’s memory and registers. The byte at address 250 (FAh) is the most significant byte. This field is compared to the four-byte OEMPW field at serial address A2h, byte 120 to 123. If the two fields match, access is allowed to the OEM areas of the MIC3001 non-volatile memory at serial addresses A4h and A6h. The OEM password may be set by writing the new value into OEMPWSET. The new password will not take effect until after a power-on reset occurs or a warm reset is performed using the RST bit in OEMCFG0. This allows the new password to be verified before it takes effect. These registers are non-volatile and will be maintained through power and reset cycles. A valid OEM password is required for access to this register. August 2004 61 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Byte Weight 3 OEM Password, Most Significant Byte 2 OEM Password, 2nd Most Significant Byte 1 OEM Password, 2nd Least Significant Byte 0 OEM Password, Least Significant Byte OEM Calibration 0 (OEMCAL0) D[7] D[6] FLTDIS read/write reserved Default Value D[5] FSPIN read/write D[4] D[3] WRINH APCCAL read/write read/write 0000 0000b = 00h Serial Address A6h = 1010011b Byte Address 16 = 10h D[2] FRCINT read/write D[1] FRCTXF read/write D[0] FRCLOS read/write A valid OEM password is required for access to this register. Bit D[7] Function Operation Reserved Always write as zero; reads undefined. D[6] FLTDIS Fault comparator disable; inhibits output of fault comparators when set. 0 = faults enabled; 1 = disabled; Read/write. D[5] FSPIN Fault comparator “spin-on-channel” mode select; do not enable ADC and FC spin-on-channel modes simultaneously. 0 = normal operation; 1 = spin on channel; Read/write. D[4] WRINH Inhibit NVRAM write cycles. 0 = normal operation; 1 = inhibit writes; Read/write. D[3] APCCAL Selects APC calibration mode - DACs may be controlled directly. 0 = normal mode; 1 = calibration mode; Read/write. D[2] FRCINT Forces the assertion of /INT 0 = normal operation; 1 = asserted; Read/write. D[1] FRCTXF Forces the assertion of TXFAULT 0 = normal operation; 1 = asserted; Read/write. D[0] FDCLOS Forces the assertion of RXLOS 0 = normal operation; 1 = asserted; Read/write. OEM Calibration 1 (OEMCAL1) D[7] reserved Default Value D[6] ADSTP read/write D[5] ADIDL read/write D[4] D[3] 1SHOT ADSPIN read/write read/write 0000 0000b = 00h Serial Address A6h = 1010011b Byte Address 17 = 11h D[2] SPIN[2] read/write D[1] SPIN[1] read/write D[0] SPIN[0] read/write A valid OEM password is required for access to this register. August 2004 62 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Bit D[7] Function Operation Reserved Always write as zero; reads undefined. D[6] ADSTP Stop ADC Halts the analog to digital converter 0 = normal operation; 1 = stopped; Read/write. D[5] ADIDL ADC idle flag 0 = busy; 1 = idle; Read/write. D[4] 1SHOT Triggers one-shot A/D conversion cycle 0 = normal operation; 1 = one-shot; Read/write. D[3] ADSPIN Selects ADC spin-on-channel mode; do not enable ADC and FC spin-onchannel modes simultaneously 0 = normal operation; 1 = spin-on-channel; Read/write. D[2], D[1], D[0] SPIN[2:0] ADC and fault comparator (FC) channel select for spin-on-channel mode; do not enable ADC and FC spin-on-channel modes simultaneously ADC: 000 = temperature; 001 = voltage; 010 = VILD; 011 = VMPD; 100 = VRX; FC: 001 = VILD; 001 = VMPD; 010 = VRX; Read/write. OEM Calibration 1 (OEMCAL1) D[7] read/write Default Value D[6] read/write D[5] read/write D[4] read/write D[3] read/write D[2] read/write D[1] read/write D[0] read/write 0000 0000b = 00h Serial Address A6h = 1010011b Byte Address 18 = 12h The look-up table index is derived from the current temperature measurement and LUTOFF as follows: where TAVG(n) is the current average temperature. This register allows the current table index to be read by the host. The table base address must be added to LUTINDX to form a complete table index in physical memory. A valid OEM password is required for access to this register. Otherwise, reads are undefined. OEM Configuration 3 (OEMCFG3) D[7] LUTSEL read/write Default Value D[6] TXFPOL read/write D[5] GPOD read/write D[4] GPOM read/write D[3] GPOC read/write D[2] TXFIN read/write D[1] LOSDIS read/write D[0] INTCAL read/write 0000 1000b = 08h Serial Address A6h = 1010011b Byte Address 19 = 13h This register is non-volatile and will be maintained through power and reset cycles. A valid OEM password is required for access to this register. GPOD and GPOC are ignored when GPOM = 0. TXFPOL is ignored if TXFIN = 0. August 2004 63 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Function Operation D[7] Bit LUTSEL RX power look-up table input selection bit 1 = RX power; 0 = temperature; read/write; ignored if INTCAL = 0. D[6] TXFPOL TXFIN active polarity select; a fault is indicated when TXFIN = TXFPOL 0 = active-low; 1 = active-high; read/write; ignored if TXFIN = 0. D[5] GPOD GPO output drive 0 = open drain; 1 = push-pull; read/write; ignored if GPOM = 0. D[4] GPOM GPO/RSOUT mode select 0 = RSOUT; 1 = GPO; read/write. D[3] GPOC GPO output control 0 = low; 1 = high; read/write; ignored if GPOM = 0. D[2] TXFIN TXFIN mode select 0 = SHDN; 1 = TXFIN; read/write. D[1] LOSDIS RXLOS comparator disable 0 = enabled; 1 = disabled; read/write. D[0] INTCAL Calibration mode select 0 = external calibration; 1 = internal calibration; read/write. BIAS DAC Setting (APCDAC) Current VBIAS Setting D[7] read only Default Value D[6] read only D[5] read only D[4] read only D[3] read only D[2] read only D[1] read only D[0] read only 0000 0000b = 00h Serial Address A6h = 1010011b Byte Address 20 = 14h This register reflects (reads back) the value set in the APC register (APCSET0, APCSET1, or APCSET2 whichever is selected). A valid OEM password is required for access to this register. Modulation DAC Setting (MODDAC) Current VMOD Setting D[7] read only Default Value D[6] read only D[5] read only D[4] read only D[3] read only D[2] read only D[1] read only D[0] read only 0000 0000b = 00h Serial Address A6h = 1010011b Byte Address 21 = 15h This register reflects (reads back) the value set in the MODSET register. A valid OEM password is required for access to this register. OEM Readback Register (OEMRD) Default Value D[3] D[4] APCSAT INT read only read only 0000 0000b = 00h Serial Address A6h = 1010011b Byte Address 22 = 16h D[7] reserved D[6] reserved D[5] reserved D[2] IBFLT read only D[1] TXFLT read only D[0] RSOUT read only This register reflects (reads back) the status of the bits corresponding to the parameters defined below. A valid OEM password is required for access to this register. Otherwise, reads are undefined and writes are ignored. August 2004 64 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Bit D[7:5] Function Operation Reserved Always write as zero; reads undefined. Mirrors state of /INT but active-high; not state of physical pin! 1 = interrupt; 0 = no interrupt. D[4] INT D[3] APCSAT APC saturation fault comparator output state 1 = fault; 0 = normal operation. D[2] IBFLT State of IBIAS over-current fault comparator output 1 = fault; 0 = normal operation; read-only. D[1] TXFLT State of transmit power fault comparator output 1 = fault; 0 = normal operation; read-only. D[0] RSOUT State of the rate select output pin, RSOUT 1 = high; 0 = low; Read-only. Signal Detect Threshold (LOSFLTn) D[7] read/write Default Value D[6] read/write D[5] read/write D[4] D[3] read/write read/write 0000 0000b = 00h Serial Address A6h = 1010011b Byte Address 23 = 17h D[2] read/write D[1] read/write D[0] read/write This register works in conjunction with the LOSFLT register to control the operation of the loss of signal comparator. The comparator’s output, RXLOS, is asserted when the input on VRX falls below the level in LOSFLT. The output will then be deasserted when the VRX signal rises above LOSFLTn. The input signal is subject to scaling by the RXPOT. If the LOS comparator is disabled, i.e., LOSDIS = 1, this register is ignored. A valid OEM password is required for access to this register. This register is non-volatile and will be maintained through power and reset cycles. RX EEPOT Tap Selection (RXPOT) D[7] reserved Default Value D[6] reserved D[5] reserved D[4] D[3] read/write read/write 0000 0000b = 00h Serial Address A6h = 1010011b Byte Address 24 = 18h D[2] read/write D[1] read/write D[0] read/write This register is non-volatile and will be maintained through power and reset cycles. A valid OEM password is required for access to these registers. Bit(s) Function Operation D[7:5] Reserved Reserved. Always write as zero; reads undefined. D[4:0] RXPOT tap selection: Read/write; non-volatile. 00000 = No divider action; POT disconnected 00001 = 31/32 00010 = 30/32 • • • 11110 = 2/32 11111 = 1/32 August 2004 65 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 OEM Configuration 4 (OEMCFG4) D[7] reserved Default Value D[6] reserved D[5] reserved D[4] D[3] reserved read/write 0000 0000b = 00h Serial Address A6h = 1010011b Byte Address 25 = 19h D[2] read/write D[1] read/write D[0] read/write This register is non-volatile and will be maintained through power and reset cycles. A valid OEM password is required for access to these registers. Bit(s) Function Operation D[7:5] Reserved Reserved. Always write as zero; reads undefined. ISTART[3:0] ISTART current level selection: Read/write; non-volatile. 0000 = No ISTART current 0001 - 1111 = 0.375mA x ISTART[3:0] ISTART is used to speed up the laser start-up after a fault accures. The charging current of the compensation cap starts from ISTART instead of ramping up from 0. Power-On Hour Meter Data (POHDATA) D[7] read/write Default Value D[6] read/write D[5] read/write D[4] D[3] read/write read/write 0000 0000b = 00h Serial Address A6h = 1010011b Byte Address 32-39 = 20h - 27h D[2] read/write D[1] read/write D[0] read/write These registers are used for backing up the POH result during power cycles. At power-up, the POH meter selects the larger of the two values as the initial count. Incremental results are stored in alternate register pairs. The power-on hour meter may be reset or preset by writing to these registers. These registers are non-volatile and will be maintained through power and reset cycles. A valid OEM password is required for access to these registers. Byte Weight 3 POHA, high-byte 2 POHA, low-byte 1 POHB, high-byte 0 POHB, low-byte OEM Scratchpad Registers (SCRATCHn) Default Value 0000 0000b = 00h Serial Address A6h = 1010011b Byte Address SCRATCH0: 126 = 7Eh SCRATCH1: 127 = 7Fh SCRATCH2: 128 = 80h ....................................... SCRATCH127: 253 = FDh The scratchpad registers are general-purpose non-volatile memory locations. They can be freely read from and written to any time the MIC3001 is in OEM mode. August 2004 66 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 RX Power Look-up Table (RXLUTn) Default Value 0000 0000b = 00h Serial Address A6h = 1010011b Byte Address 40-71 = 28h - 47h These registers are non-volatile and will be maintained through power and reset cycles. A valid OEM password is required for access to these registers. Bytes Definition RXSLP0h RX Slope 0, High Byte. RXSLP0l RX Slope 0, Low Byte. RXOFF0h RX Offset 0, High Byte. RXOFF0l RX Offset 0, Low Byte. RXSLP1h RX Slope 1, High Byte. RXSLP1l RX Slope 1, Low Byte. RXOFF1h RX Offset 1, High Byte. RXOFF1l • • • RXSLP7h RX Offset 1, Low Byte. • • • RX Slope 7, High Byte. RXSLP7l RX Slope 7, Low Byte. RXOFF7h RX Offset 7, High Byte. RXOFF7l RX Offset 7, Low Byte. Calibration Constants (CALn) Default Value 0000 0000b = 00h Serial Address A6h = 1010011b Byte Address 74 - 87 = 4A h - 57h These registers are non-volatile and will be maintained through power and reset cycles. A valid OEM password is required for access to these registers. Bytes Definition TOFFh Temperature Offset, High Byte. TOFF0l Temperature Offset, Low Byte. Always Reads Zero; Writes Ignored. VSLP0h Voltage Slope, High Byte. VSLP0l Voltage Slope, Low Byte. VOFFh Voltage Offset, High Byte. VOFF0l Voltage Offset, Low Byte. ISLP0h Bias Current Slope, High Byte. ISLP0l Bias Current Slope, Low Byte. IOFFh Bias Current Offset, High Byte. IOFF0l Bias Current Offset, Low Byte. TXSLPh TX Power Slope, High Byte. TXSLPl TX Power Slope, Low Byte. TXOFFh TX Power Offset, High Byte. TXOFFl TX Power Offset, Low Byte. August 2004 67 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Manufacturer ID Register (MFG_ID) Identifies Micrel as the manufacturer of the device. Always returns 2Ah D[7] read only Default Value D[6] read only D[5] read only D[4] D[3] read only read only 0000 0000b = 00h Serial Address A6h = 1010011b Byte Address 32-39 = 20h - 27h D[2] read only D[1] read only D[0] read only These registers are used for backing up the POH result during power cycles. At power-up, the POH meter selects the larger of the two values as the initial count. Incremental results are stored in alternate register pairs. The power-on hour meter may be reset or preset by writing to these registers. These registers are non-volatile and will be maintained through power and reset cycles. A valid OEM password is required for access to these registers. Bit(s) Function Operation D[7:0] Identifies Micrel as the manufacturer of the device. Always returns 2Ah. Read only. Always returns Ah Device ID Register (DEV_ID) D[7] read only D[6] read only D[5] read only D[4] read only D[3] read only MIC3001 DEVICE ID always reads 0 at D[5-7] and 1 at D[4] Default Value 0001 xxxxb = 1xh Serial Address A6h = 1010011b Byte Address 255 = FFh D[2] read only D[1] read only D[0] read only DIE REVISION The value in this register, in combination with the MFG_ID register, serve to identify the MIC3001 and its revision number to software. This register is read-only. August 2004 68 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Applications Information Controlling Laser Diode Bias Figure 26. Example APC Circuit for Common-Cathode TOSA Figure 27. Example APC Circuit for Common Anode TOSA August 2004 69 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Choosing CCOMP The APC loop is compensated by a capacitor, CCOMP, connected from COMP to either VDDA or GNDA. This capacitor adjusts the slew rate and bandwidth of the loop as follows: Application CCOMP (nF) 8b/10b encoding, ≥1Gbps, tON ≤ 1ms 10 SONET (62b/64b encoding), ≥1Gbps 22 ≥155Mbps, tON ≤ 1ms 22 ≥155Mbps 100 Table 22. Typical Values for CCOMP where: ISLEW = 64µA, GM = 125µMho these relationships are shown graphically in Figure 28 and Figure 29. Figure 28. Slew Rate vs. CCOMP Value Figure 29. Open Loop Unity-Gain Bandwidth vs. CCOMP The loop response should be tailored to the data rate, encoding format and maximum run-lengths, and required laser turn-on time. Higher data rates and/or shorter maximum run lengths and/or faster turn-on times call for smaller capacitors. Lower data rates and/or longer maximum run lengths and/or slower turn-on times call for larger capacitors. In order to meet the SFP/GBIC turn-on requirement of 1ms, for example, do not employ a capacitor larger than 20nF. Low ESR capacitors such as ceramics will give the best results. Excessive ESR will reduce the effectiveness of CCOMP. The capacitor’s voltage rating must exceed VDDA. Some typical values are shown in Table 22. August 2004 While there is no theoretical upper limit on the size of CCOMP, it is desirable for the loop to be able to track the changes resulting from periodic temperature compensation. The typical temperature compensation update period is 1.6s. Therefore, a maximum size of 1mF is recommended. If laser turn-on time is not a factor, a value between 100nF and 1mF can be used for virtually any typical application. The tradeoff is that higher value capacitors have a larger physical size and cost. In order to maximize the power supply rejection ratio (PSRR), CCOMP should be returned to GNDA when the VBIAS output is sourcing current, e.g., driving an NPN transistor (SRCE bit = 1). CCOMP should be returned to VDDA when the VBIAS output is sinking current, e.g., driving a PNP transistor (SRCE bit =0). Measuring Laser Bias Current VILD+ and VILD– form a pair of pseudo-differential A/D inputs for measuring laser diode bias current via a sense resistor. The signal applied to these inputs is converted to a single-ended, ground-referenced signal for input into the ADC and bias current fault comparator. These inputs have limited common-mode voltage range. The full-scale differential input range is VREF/4 or about 300mV. Figure 26 and Figure 27 illustrate the typical implementation of this function. Note that VILD– is always connected to the circuit’s reference potential: VDD in the case of a common-anode transmitter optical subassembly (TOSA) and GND in the case of a commoncathode TOSA. Note that the monitor photodiode current will also flow in the sense resistor. This will result in a small offset in the measured bias current. The APC function will hold this term constant, so it can be corrected for in the external calibration constants. The sensing resistor could also be connected between VDD and the emitter of Q1 on figure 26 or between the emitter of Q1 and GND on Figure 27. Interfacing To Laser Drivers In order for the MIC3001 to control the modulation current of the laser diode, an interface circuit may be required depending on the method used by the driver to set its modulation current level. Generally, most laser diode driver ICs use one of three methods: a) A current, ISET, is sourced into a pin on the driver IC. The modulation current delivered by the driver is then some fixed multiple of ISET. The SY88912 is an example of this type of driver. A simple circuit 70 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. can be used to create a current source controlled by the VMOD outputs. The circuit is based on an external bipolar transistor and a current sensing resistor. b) A current, ISET, is drawn out of a pin on the driver IC. The modulation current delivered by the driver is then some fixed multiple of ISET. A simple circuit can be used to create a current source controlled by the VMOD outputs. The circuit is based on an external bipolar transistor and a current sensing resistor. c) A voltage, VSET, is applied to a pin on the driver IC. This voltage may be referenced to GND or VDD. The MIC3001’s VMOD+ output can supply this voltage directly. If a voltage swing wider than VREF is needed, gain can be applied with a pair of external resistors. The SY88932, SY88982, and SY89307 are examples of this type of driver. SY88912 3.3V 3.2Gbps SONET/SDH Laser Driver The modulation level of the SY88912 driver is controlled by the current sourced into the RSET pin (Type (a) above). The circuit shown in Figure 30.allows the MIC3001’s VMOD outputs to control the SY88912’s modulation current from its minimum value, 5mA, to its maximum value, 60mA. The circuit operates as a DAC-controlled current source. The current source is formed by the VMOD buffer amplifier, external transistor, and current sense resistor. The op-amp acts to force the voltage drop across RSET to be equal to the DAC output voltage. The current, ISET, through RSET is therefore regulated as ISET = VMOD+/RSET (In this case, the DAC output and therefore the op-amp output, are referenced to VDDA.) The SY88912’s current gain, IMOD/ISET, is 23. A modulation current level of 60mA requires ISET = 60mA/23 = 2.61mA; a modulation current level of 5mA requires ISET = 5mA/23 = 0.217mA. RFLTR and CFLTR are optional and act to eliminate any noise that might be present on VDDA or VMOD. The values shown give a 100ms time constant. Note that the time constant is present whenever the laser is turned on or turned off. This must be taken into account when designing to system specifications such as the SFP MSA’s tON and tOFF requirements. The values of RFLTR and/or CFLTR may need to be adjusted accordingly. The impact of the filter time constant on the turn off time can be eliminated by using the MIC3001’s SHDN signal to drive the SY88912’s enable input, /EN. The use of the SHDN signal is completely optional. The main benefit to using SHDN, however, is that it shuts down the driver very quickly and irrespective of the values of RFLTR and CFLTR. The values of RFLTR and CFLTR can therefore be increased, enhancing their effect without incurring any turn-off time penalty. Depending on the polarity chosen for SHDN using the SPOL bit, an inversion may be required between the MIC3001’s SHDN output and the driver’s /EN input. (The SHDN output may also be used to drive a redundant safety switch and the same polarity may not be appropriate for both functions.) August 2004 MIC3001 Figure 30. Controlling the SY88912 Modulation Current For the circuit of Figure 30, the modulation current control range and corresponding DAC values are shown in Table 23 below. DAC VDDA-VMOC ISET IMOD 0 0V 0mA 0mA 19 0.091V 0.216mA 4.98mA 127 0.61V 1.45mA 33.4mA 255 1.22V 2.91mA 66.8mA Table 23. Control Range of SY88912 Modulation Control Circuit SY88932 3.3V 3.2Gbps SONET/SDH Laser Driver The modulation level of the SY88932 driver is controlled by the voltage applied to the VCTRL pin (Type (c) above). The circuit shown in Figure 31 allows the MIC3001’s VMOD output to control the SY88932’s modulation current. The circuit operates as a DACcontrolled voltage source. VCTRL is simply the DAC output voltage. See section above on SY88912 for RFLTR, CFLTR and SHDN. Figure 31. Controlling the SY88932 Modulation Current 71 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 SY89307 5.0V/ 3.3V 2.5Gbps VCSEL Driver The modulation level of the SY89307 driver is controlled by the voltage applied to the VCTRL pin (Type (c) above). The circuit shown in Figure 32 allows the MIC3001’s VMOD output to control the SY89307’s output swing. VCTRL is simply the DAC output voltage. The circuit operates as a DAC-controlled voltage source. See section above on SY88912 for RFLTR, CFLTR. Figure 33. Controlling the Modulation Current via a Sink Current Figure 32. Controlling the SY89307 Modulation Current Laser Drivers Programmed via a Sink Current The modulation level of some laser diode drivers is controlled by a current sourced out of the RSET pin (Type (b) above). The circuit shown in Figure 33 allows the MIC3001’s VMOD outputs to control the set current, ISET. The circuit operates as a DAC-controlled current sink. The current sink is formed by the VMOD buffer amplifier, external transistor, and current sense resistor. The op-amp acts to force the voltage drop across RSET to be equal to the DAC output voltage. The current through RSET is therefore regulated as IRSET = VMOD+/RSET. ISET is given by the equation: (13) where b is the DC gain of Q1 The higher the gain of the transistor, the closer ISET will be to the current in RSET. RFLTR and CFLTR act to eliminate any noise that might be present on VDDA or VMOD. The values shown give a 100ms time constant. See section above on SY88912 for RFLTR, CFLTR and SHDN. August 2004 Drivers with Monitor Outputs Laser diode driver ICs have been introduced with monitor outputs. These outputs provide ground-referred signals that mirror critical signals like laser bias current, modulation current or monitor photodiode current, an analog of transmitted power. Generally, these outputs source a current into an external resistor to generate a ground-referenced voltage. Using these outputs with the MIC3001 is straightforward since the MIC3001’s VILD+/– and VMPD inputs are polarity programmable, Shutdown Output The shutdown output, SHDN, can be used in two ways: as an enable or on/off control for the laser driver IC, and/or to control a redundant switch in the laser current path. The redundant switch provides a means for the MIC3001 to shut off the laser current even if the bias transistor or modulator is damaged or fails. SHDN is active any time the MIC3001 shuts down the laser, i.e., if the TXDISABLE function is asserted in hardware or software, or if the fault detection circuits trigger laser shutdown. The shutdown output, SHDN, is essentially a logic output with programmable polarity. The programmable polarity allows SHDN to drive either high-side or low-side switches or active-high or activelow enable inputs without the need for external inversion circuits. If an active-low and an active-high shutdown signal are required, an external inverter will be necessary. Examples of redundant switch circuits are shown in Figure 34. 72 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Remote Sensing For remote temperature sensing using the XPN pin, most small-signal PNP transistors with characteristics similar to the JEDEC 2N3906 will perform well as thermal diodes. Table 24 lists several examples of such parts that Micrel has tested for use with the MIC3001. Other transistors equivalent to these should also work well. Vendor Part Number Package Fairchild Semiconductor MMBT3906 SOT-23 On Semiconductor MMBT3906L SOT-23 Infineon Technologies SMBT3906/MMBT3906 SOT-23 Samsung Semiconductor KST3906-TF SOT-23 Figure 34. Redundant Switch Circuits Temperature Sensing The MIC3001 can measure and report its own internal temperature or the temperature of a remote PN junction or “thermal diode”. In either case it is important to note that any board-mounted semiconductor device tends to track the ground plane temperature around it. The dominant thermal path to the sensor is often the ground pin. The ground pin usually connects to the lead-frame paddle on which the die is mounted. Typical semiconductor packages, being non-conductive plastic, insulate the device from the ambient air. The advantage to using a remote sensor is that the temperature may be sensed at a specific location, such as in the proximity of the laser diode, or away from any heat sources where it will more closely track the transceiver’s case temperature. The measured temperature is reported via the digital diagnostics registers and is used to index the temperature compensation tables. (Note: SFF-8472 does not specify the meaning of the reported temperature information or the location from which it is taken. This information is to be specified in the transceiver vendor’s datasheet.) August 2004 Table 24. Transistors Suitable for Use as Remote Diodes Minimizing Errors Self-Heating One concern when measuring temperature is to avoid errors induced by self-heating. Self-heating is caused by power dissipation within the MIC3001. It is directly proportional to the internal power dissipation and the junction-to-ambient thermal resistance, θJA. The dissipation in the MIC3001 must be calculated and reduced to a temperature offset. The power dissipation, PDISS, includes the effect of quiescent current and all currents flowing into or out of any signal pins, especially VBIAS and VMOD. The temperature rise caused by self-heating is given by: (14) θJA is given in the “Operating Ratings” section above as 43°C/W. The possible contributors to self-heating are listed in Table 25. The numbers given in Table 25 suggest that the power dissipation in a typical application will be no more than a few tens of milliwatts, leading to selfheating on the order of 1°C. 73 M9999-082404-A hbwhelp@micrel.com or (408) 955-1690 Micrel, Inc. MIC3001 Description Magnitude Notes Quiescent Power IDD x VDD Typically VDD = 3.3V, IDD = 2.7mA → 3.3V x 2.7mA = 8.91mW. SHDN Current IOL x VOL Negligible if MOSFET is used as shutdown device. TXFAULT Current IOL x VOL Worst case is VDD2/RPULLUP; RPULLUP is 4.7kΩ min. per SFP MSA → 3.3V2/4.7kΩ = 2.32mW. VBIAS Current VBIAS x IVBIAS or (VDD–VBIAS) x IVBIAS Worst-case is VREF x 10mA = 1.22V x 10mA = 12.3mW. VMOD Current VMOD x IVMOD or (VDD–VMOD) x IVMOD Worst-case is VREF x 10mA = 1.22V x 10mA = 12.3mW. RSOUT Current IOL x VOL Only for rate-agile applications using RSIN/RSOUT. DATA Current IOL x VOL x duty_cycle May be negligible; Depends on bus speed, pull-up current, and bus activity. RXLOS Current IOL x VOL Worst case is VDD2/RPULLUP; RPULLUP is 4.7kΩ min. per SFP MSA → 3.3V2/4.7kΩ = 2.32mW. Table 25. Contributors to Self-Heating In any application, the best and often easiest approach is to measure performance in the final application environment. This is especially true when dealing with systems for which some temperature data may be poorly defined or unobtainable except by empirical means. If desired, the external calibration constants may be used to correct the temperature readings. Series Resistance with External Temperature Sensor The operation of the MIC3001 depends upon sensing the VCB-E of a diode-connected PNP transistor (“diode”) at two different current levels. For remote temperature measurements, this is done using an external diode connected between XPN and ground. Since this technique relies upon measuring the relatively small voltage difference resulting from two levels of current through the external diode, any resistance in series with the external diode will cause an error in the temperature reading from the MIC3001. A good rule of thumb is this: for each ohm in series with the external transistor, there will be a 0.9°C error in the MIC3001’s temperature measurement. It is not difficult to keep the series resistance well below an ohm (typically