ONET4291PARGVR

ONET4291PA www.ti.com SLLS671 – SEPTEMBER 2005 1-Gbps to 4.25-Gbps Rate-Selectable Limiting Amplifier FEATURES • • • • • • • • Multirate Operation from 1 Gbps up to 4.25 Gbps Loss-of-Signal Detection (LOS) Two-Wire Digital Interface Digitally Selectable LOS Threshold Digitally Selectable Bandwidth Digitally Selectable Output Voltage Low Power Consumption Input Offset Cancellation • • • CML Data Outputs With On-Chip, 50-Ω Back-Termination to VCC Single 3.3-V Supply Surface-Mount, Small-Footprint, 4-mm × 4-mm, 16-Terminal QFN Package APPLICATIONS • • • Multirate SONET/SDH Transmission Systems 4.25-Gbps, 2.125-Gbps, and 1.0625-Gbps Fibre-Channel Receivers Gigabit Ethernet Receivers DESCRIPTION The ONET4291PA is a versatile, high-speed, rate-selectable limiting amplifier for multiple fiber-optic applications with data rates up to 4.25 Gbps. The device provides a two-wire interface, which allows digital bandwidth selection, digital output amplitude selection, and digital loss of signal threshold adjust. This device provides a gain of about 43 dB, which ensures a fully differential output swing for input signals as low as 5 mVp-p. The ONET4291PA provides loss-of-signal detection with either digital or analog threshold adjust. The part is available in a small-footprint, 4-mm × 4-mm, 16-terminal QFN package. It requires a single 3.3-V supply. This power-efficient, rate-selectable limiting amplifier is characterized for operation from –40°C to 85°C ambient temperature. Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of the Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. Copyright © 2005, Texas Instruments Incorporated ONET4291PA www.ti.com SLLS671 – SEPTEMBER 2005 BLOCK DIAGRAM A simplified block diagram of the ONET4291PA is shown in Figure 1. This compact, 3.3-V, low-power, 1-Gbps to 4.25-Gbps rate-selectable limiting amplifier consists of a high-speed data path with offset cancellation block (dc feedback), a loss-of-signal detection block using two peak detectors, a programmable resistor, a two-wire interface and control-logic block, and a band-gap voltage reference and bias-current generation block. DC Feedback Stage COC+ + COC− − 50 Ω Band-Gap Voltage Reference and Bias Current Generation 50 Ω CML Output Buffer DIN+ DIN− Bandwidth Switch + + + DOUT+ − − − DOUT− Gain Stage VCC 4 Gain Stage Peak Detector GND Peak Detector 2 2 SDA SCK Two-Wire Interface and Control Logic 6 Programmable Resistor Loss-of-Signal Detection RTHI TH LOS SD B0067-01 Figure 1. Simplified Block Diagram of the ONET4291PA HIGH-SPEED DATA PATH The high-speed data signal is applied to the data path by means of the input signal terminals DIN+ and DIN–. The data path consists of a digitally controllable bandwidth switch followed by two 50-Ω on-chip line termination resistors; two gain stages, which provide a typical gain of about 37 dB; and a CML output stage, which provides another 6-dB gain. The amplified data-output signal is available at the output terminals DOUT+ and DOUT–, which feature on-chip 2 × 50-Ω back-termination to VCC. A dc feedback stage compensates for internal offset voltages and thus ensures proper operation even for small input data signals. This stage is driven by the output signal of the second gain stage. The signal is low-pass filtered, amplified, and fed back to the input of the first gain stage via the on-chip 50-Ω termination resistors. The required low-frequency cutoff is determined by an external 0.1-µF capacitor, which must be differentially connected to the COC+ and COC– terminals. LOSS-OF-SIGNAL DETECTION AND PROGRAMMABLE RESISTOR The peak values of the output signals of the first and second gain stages are monitored by two peak detectors. The peak values are compared to a predefined loss-of-signal threshold voltage inside the loss-of-signal detection block. As a result of the comparison, the loss-of-signal detection block generates the SD signal, which indicates a sufficient input-signal amplitude, or the LOS signal, which indicates that the input signal amplitude is below the defined threshold level. 2 ONET4291PA www.ti.com SLLS671 – SEPTEMBER 2005 The threshold voltage can be set within a certain range by means of an external resistor connected between the TH terminal and ground (GND). Alternatively, shorting the TH and RTHI terminals causes an internal, digitally selectable resistor to be used for threshold adjustment. The resistor value is selectable using the two-wire interface. The principle of the digitally selectable resistor is shown in Figure 2. The complete resistor between the RTHI terminal and GND consists of seven series-connected resistors. Six of the resistors have binary-weighted resistance values, and each can be shunted individually by means of a parallel-connected MOS transistor. The seventh resistor defines the minimum remaining resistance in case all six MOS devices are conductive. With the resistor values shown in Figure 2, the minimum selectable resistance is 8 kΩ, the maximum resistance is 86.75 kΩ, and the resolution is 1.25 kΩ/step. RTHI R5 20 kΩ LOS Threshold Register From 2-Wire Interface and Control Logic Block R6 40 kΩ R7 8 kΩ R4 10 kΩ R3 5 kΩ R2 2.5 kΩ R1 1.25 kΩ S0098-01 Figure 2. Digitally Controllable On-Chip Resistor 3 ONET4291PA www.ti.com SLLS671 – SEPTEMBER 2005 TWO-WIRE INTERFACE AND CONTROL LOGIC The ONET4291PA uses a two-wire serial interface for digital control of the amplifier bandwidth, output amplitude, and LOS threshold. A simplified block diagram of this interface is given in Figure 3. SDA and SCK are inputs for the serial data and the serial clock, respectively, and can be driven by a microprocessor. Both inputs have 100-kΩ pullup resistors to VCC. For driving these inputs, an open-drain output is recommended. A write cycle consists of a START command, 3 address bits with MSB first, 8 data bits with MSB first, and a STOP command. In idle mode, both the SDA and SCK lines are at a high level. A START command is initiated by a falling edge on SDA with SCK at a high level. Bits are clocked into an 11-bit-wide shift register while the SCK level is high. A STOP command is detected on the rising edge of SDA after SCK has changed from a low level to a high level. At the time of detection of a STOP command, the 8 data bits from the shift register are copied to a selected 8-bit register. Register selection occurs according to the 3 address bits in the shift register, which are decoded to 8 independent select signals using a 3-to-8 decoder block. In the ONET4291PA, only addresses 4 (100b) and 5 (101b) are used. SDA 11-Bit Shift Register SCK 8 Bits Data 3 Bits Addr 3 8 8 START 000 001 STOP 010 8 8-Bit Register LOS Threshold (6 Bits) Output Amplitude (2 Bits) 011 100 101 3-to-8 Decoder Start/Stop Detector Logic 8-Bit Register Bandwidth (4 Bits) Unused (4 Bits) 110 111 B0068-01 Figure 3. Simplified Two-Wire Interface Block Diagram 4 ONET4291PA www.ti.com SLLS671 – SEPTEMBER 2005 The timing definition for the serial data signal SDA and the serial clock signal SCK is shown in Figure 4. START 1 0 1 0 1 1 STOP DTAF DTAR DTAHI DTAWT SDA SCK STRTHLD DTASTP CLKR DTAHLD CLKF STOPSTP CLKHI T0077-01 DESCRIPTION MIN STRTHLD PARAMETER START hold time Time required from data falling edge to clock falling edge at START 10 MAX UNIT CLKR, DTAR Clock and data rise time Clock and data rise time CLKF, DTAF Clock and data fall time Clock and data fall time CLKHI Clock high time Minimum clock high period 50 ns DTAHI Data high time Minimum data high period 100 ns DTASTP Data setup time Minimum time from data rising edge to clock rising edge 10 ns DTAWT Data wait time Minimum time from data falling edge to data rising edge 50 ns DTAHLD Data hold time Minimum time from clock falling edge to data falling edge 10 ns STOPSTP STOP setup time Minimum time from clock rising edge to data rising edge at STOP 10 ns ns 10 ns 10 ns Figure 4. Two-Wire Interface Timing Diagram The register mapping for register addresses 4 (100b) and 5 (101b) is shown in Table 1 and Table 2, respectively. Table 1. Register 4 (100b) Mapping BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0 BW3 BW2 BW1 BW0 – – – – Table 2. Register 5 (101b) Mapping BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0 A1 A0 R5 R4 R3 R2 R1 R0 Table 3 through Table 5 describe circuit functionality based on the register settings. 5 ONET4291PA www.ti.com SLLS671 – SEPTEMBER 2005 Table 3. Bandwidth Selection BW3 BW2 BW1 BW0 TYP UNIT 0 0 0 0 4.39 GHz 0 0 0 1 3.91 GHz 0 0 1 0 3.47 GHz 0 0 1 1 3.03 GHz 0 1 0 0 2.81 GHz 0 1 0 1 2.31 GHz 0 1 1 0 1.82 GHz 0 1 1 1 1.60 GHz 1 0 0 0 1.55 GHz 1 0 0 1 1.33 GHz 1 0 1 0 1.11 GHz 1 0 1 1 1.03 GHz 1 1 0 0 0.86 GHz 1 1 0 1 0.82 GHz 1 1 1 0 0.76 GHz 1 1 1 1 0.73 GHz Table 4. Output Amplitude Selection A1 A0 TYP UNIT 0 0 400 mVp-p 0 1 600 mVp-p 1 0 800 mVp-p 1 1 1000 mVp-p Table 5. LOS-Threshold Digitally Controlled Resistor Selection 6 R5 R4 R3 R2 R1 R0 TYP UNIT 0 0 0 0 0 0 86.75 kΩ 0 0 0 0 0 1 85.5 kΩ 0 0 0 0 1 0 84.25 kΩ 0 0 0 0 1 1 83 kΩ 0 0 0 1 0 0 81.75 kΩ 0 0 0 1 0 1 80.5 kΩ 0 0 0 1 1 0 79.25 kΩ 0 0 0 1 1 1 78 kΩ 0 0 1 0 0 0 76.75 kΩ 0 0 1 0 0 1 75.5 kΩ 0 0 1 0 1 0 74.25 kΩ 0 0 1 0 1 1 73 kΩ 0 0 1 1 0 0 71.75 kΩ 0 0 1 1 0 1 70.5 kΩ 0 0 1 1 1 0 69.25 kΩ 0 0 1 1 1 1 68 kΩ 0 1 0 0 0 0 66.75 kΩ 0 1 0 0 0 1 65.5 kΩ 0 1 0 0 1 0 64.25 kΩ 0 1 0 0 1 1 63 kΩ 0 1 0 1 0 0 61.75 kΩ ONET4291PA www.ti.com SLLS671 – SEPTEMBER 2005 Table 5. LOS-Threshold Digitally Controlled Resistor Selection (continued) R5 R4 R3 R2 R1 R0 TYP UNIT 0 1 0 1 0 0 1 0 1 1 1 60.5 kΩ 0 59.25 0 1 0 1 kΩ 1 1 58 kΩ 0 1 1 0 1 1 0 0 0 56.75 kΩ 0 0 1 55.5 0 1 kΩ 1 0 1 0 54.25 kΩ 0 0 1 1 0 1 1 53 kΩ 1 1 1 0 0 51.75 kΩ 0 1 1 1 0 1 50.5 kΩ 0 1 1 1 1 0 49.25 kΩ 0 1 1 1 1 1 48 kΩ 1 0 0 0 0 0 46.75 kΩ 1 0 0 0 0 1 45.5 kΩ 1 0 0 0 1 0 44.25 kΩ 1 0 0 0 1 1 43 kΩ 1 0 0 1 0 0 41.75 kΩ 1 0 0 1 0 1 40.5 kΩ 1 0 0 1 1 0 39.25 kΩ 1 0 0 1 1 1 38 kΩ 1 0 1 0 0 0 36.75 kΩ 1 0 1 0 0 1 35.5 kΩ 1 0 1 0 1 0 34.25 kΩ 1 0 1 0 1 1 33 kΩ 1 0 1 1 0 0 31.75 kΩ 1 0 1 1 0 1 30.5 kΩ 1 0 1 1 1 0 29.25 kΩ 1 0 1 1 1 1 28 kΩ 1 1 0 0 0 0 26.75 kΩ 1 1 0 0 0 1 25.5 kΩ 1 1 0 0 1 0 24.25 kΩ 1 1 0 0 1 1 23 kΩ 1 1 0 1 0 0 21.75 kΩ 1 1 0 1 0 1 20.5 kΩ 1 1 0 1 1 0 19.25 kΩ 1 1 0 1 1 1 18 kΩ 1 1 1 0 0 0 16.75 kΩ 1 1 1 0 0 1 15.5 kΩ 1 1 1 0 1 0 14.25 kΩ 1 1 1 0 1 1 13 kΩ 1 1 1 1 0 0 11.75 kΩ 1 1 1 1 0 1 10.5 kΩ 1 1 1 1 1 0 9.25 kΩ 1 1 1 1 1 1 8 kΩ 7 ONET4291PA www.ti.com SLLS671 – SEPTEMBER 2005 BAND-GAP VOLTAGE AND BIAS GENERATION The ONET4291PA limiting amplifier is supplied by a single, 3.3-V supply voltage connected to the VCC terminals. This voltage is referred to GND. On-chip band-gap voltage circuitry generates a reference voltage, independent of supply voltage, from which all other internally required voltages and bias currents are derived. TERMINAL ASSIGNMENTS For the ONET4291PA, a small-footprint 4-mm × 4-mm, 16-terminal QFN package is used, with a terminal pitch of 0,65 mm. GND DOUT+ DOUT− GND RGV PACKAGE (TOP VIEW) 16 15 14 13 11 VCC SCK 3 10 TH SDA 4 9 5 6 7 8 DIN− SD 2 DIN+ VCC COC+ 12 COC− LOS 1 RTHI P0030-01 TERMINAL DESCRIPTION TERMINAL TYPE DESCRIPTION 6 Analog Offset cancellation filter capacitor plus terminal. An external 0.1-µF filter capacitor must be connected between this terminal and COC– (terminal 5). COC– 5 Analog Offset cancellation filter capacitor minus terminal. An external 0.1-µF filter capacitor must be connected between this terminal and COC+ (terminal 6). DIN+ 7 Analog input Non-inverted data input. On-chip 50-Ω terminated to COC+. Differentially 100-Ω terminated to DIN–. DIN– 8 Analog input Inverted data input. On-chip 50-Ω terminated to COC–. Differentially 100-Ω terminated to DIN+. DOUT+ 15 CML output Non-inverted data output. On-chip 50-Ω back-terminated to VCC. DOUT– 14 CML output Inverted data output. On-chip 50-Ω back-terminated to VCC. NAME NO. COC+ GND 13, 16, EP Supply LOS 1 Open-drain MOS RTHI 9 Analog SCK 3 CMOS input SD 2 CMOS output SDA 4 CMOS input Two-wire interface serial data input. Includes a 100-kΩ pullup resistor to VCC. TH 10 Analog input LOS threshold adjustment with resistor to GND. For use of the internal digitally controlled resistor, connect TH with RTHI (terminal 9). VCC 11, 12 Supply 8 Circuit ground. Exposed die pad (EP) must be grounded. High level indicates that the input signal amplitude is below the programmed threshold level. Open-drain output. Requires an external 10-kΩ pullup resistor to VCC for proper operation. Digitally controlled internal resistor to ground, which can be used for LOS threshold adjustment. A 6-bit-wide control register can be set via the two-wire interface. Two-wire interface serial clock. Includes a 100-kΩ pullup resistor to VCC. High level indicates that sufficient input signal amplitude is applied to the device. Low level indicates that the input signal amplitude is below the programmed threshold level. 3.3-V, +10%/–12% supply voltage ONET4291PA www.ti.com SLLS671 – SEPTEMBER 2005 ABSOLUTE MAXIMUM RATINGS over operating free-air temperature range (unless otherwise noted) (1) (2) VCC Supply voltage VDIN+, VDIN– Voltage at DIN+, DIN– (2) 0.5 V to 4 V VLOS, VSD, VSCK, VSDA, VCOC+, VCOC–, VRTHI, VTH, VDOUT+, VDOUT– Voltage at LOS, SD, SCK, SDA, COC+, COC–, RTHI, TH, DOUT+, DOUT– (2) –0.3 V to 4 V VDIN,DIFF Differential voltage between DIN+ and DIN– ±1.25 V ILOS Current into LOS 10 mA IDIN+, IDIN–, IDOUT+, IDOUT– Continuous current at inputs and outputs 20 mA ESD ESD rating at all terminals (HBM) TJ,max Maximum junction temperature Tstg Storage temperature range –65°C to 85°C TA Characterized free-air operating temperature range –40°C to 85°C TLEAD Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds (1) (2) –0.3 V to 4 V 4 kV 125°C 260°C Stresses beyond those listed under "absolute maximum ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under "recommended operating conditions" is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. All voltage values are with respect to network ground terminal. RECOMMENDED OPERATING CONDITIONS over operating free-air temperature range (unless otherwise noted) MIN NOM MAX 3.3 3.6 V 85 °C VCC, VCCO Supply voltage 2.9 TA Operating free-air temperature –40 CMOS input high voltage 2 UNIT V CMOS input low voltage 0.8 V DC ELECTRICAL CHARACTERISTICS over recommended operating conditions (unless otherwise noted). Typical values are at VCC = 3.3 V and TA = 25°C. PARAMETER VCC, VCCO IVCC Supply current RIN, ROUT (1) MIN TYP MAX 2.9 3.3 3.6 VOD = 1000 mVp-p, maximum bandwidth selected 35 50 64 VOD = 800 mVp-p, maximum bandwidth selected 32 46 59 VOD = 600 mVp-p, maximum bandwidth selected 28 41 53 VOD = 400 mVp-p, maximum bandwidth selected 24 36 48 UNIT V mA Ω Data input/output resistance Single-ended CMOS output high voltage ISINK = 1 mA CMOS output low voltage ISOURCE = 1 mA 0.5 V LOS low voltage ISOURCE = 1.5 mA 0.5 V 62 kΩ Optimum LOS threshold resistor (1) TEST CONDITIONS Supply voltage 50 2.3 12 V Use of the bandwidth select switch increases current consumption. The MSB bandwidth-select bit, BW3, typically consumes 5 mA, BW2 2.6 mA, BW1 1.3 mA, and BW0 0.7 mA. 9 ONET4291PA www.ti.com SLLS671 – SEPTEMBER 2005 AC ELECTRICAL CHARACTERISTICS over recommended operating conditions (unless otherwise noted). Typical operating condition is at VCC = 3.3 V and TA = 25°C. PARAMETER TEST CONDITIONS MIN TYP MAX Maximum bandwidth selected (BW3 = BW2 = BW1 = BW0 = 0) 3.5 4.5 6 Minimum bandwidth selected (BW3 = BW2 = BW1 = BW0 = 1) 0.7 f3dB-H High-frequency –3-dB bandwidth f3dB-L Low-frequency –3-dB bandwidth COC = 0.1 µF Data rate Maximum bandwidth selected (BW3 = BW2 = BW1 = BW0 = 0) vIN,MIN A Data input sensitivity GHz 23 4.25 1.9 2.7 VOD-min ≥ 0.95 * VOD (at VIN = 25 mVp-p) (gain limited) 8 14 mVp-p 38 43 Small-signal gain vs supply voltage VCC DJ Data input overload Deterministic jitter 17 vIN = 25 mVp-p, K28.5 at 4.25 Gbps, maximum bandwidth 8 15 Input = 5 mVp-p, maximum bandwidth 3 Output rise time tF Output fall time Input = 10 mVp-p, maximum bandwidth 700 850 1000 20% to 80%, vIN > 25 mVp-p, maximum bandwidth 45 90 ps 20% to 80%, vIN > 25 mVp-p, maximum bandwidth 45 90 ps K28.5 pattern at 4.25 Gbps, RTH = 62 kΩ 5.5 K28.5 pattern at 4.25 Gbps, RTH = 12 kΩ 30 10 K28.5 pattern at 4.25 Gbps mVp-p mVp-p 1 LOS threshold variation vs supply voltage VCC LOS deassert time psp-p psRMS 1.5 LOS threshold variation vs temperature TLOS_DEA mVp-p 9 tR LOS assert time dB vIN = 10 mVp-p, K28.5 at 4.25 Gbps, maximum bandwidth 800-mV output amplitude selected (default), vIN > 25 mVp-p LOS hysteresis 1 18 Differential-data output voltage TLOS_AST dB 10 VOD LOS assert threshold range dB 2000 Random jitter VTH 46 2.5 vIN = 5 mVp-p, K28.5 at 4.25 Gbps, maximum bandwidth RJ kHz Gbps Small-signal gain vs temperature vIN,MAX 50 K28.5 at 4.25 Gbps, BER < 10–12 (noise limited) Small-signal gain UNIT dB 1.5 dB 2 7.4 dB 400 1500 ns 15 80 ns ONET4291PA www.ti.com SLLS671 – SEPTEMBER 2005 TYPICAL CHARACTERISTICS Typical operating condition is at VCC = 3.3 V and TA = 25°C. FREQUENCY RESPONSE FOR DIFFERENT BANDWIDTH SETTINGS BANDWIDTH vs REGISTER-4 SETTING 5 45 43 4 41 Bandwidth − GHz Gain − dB 39 37 35 33 3 2 31 1 29 27 0 25 0.1 1 00 10 20 30 40 50 60 70 80 90 A0 B0 C0 D0 E0 F0 10 Register 4 Setting − Hex f − Frequency − GHz G002 Figure 5. Figure 6. DIFFERENTIAL INPUT RETURN GAIN vs FREQUENCY (MAXIMUM BANDWIDTH) RANDOM JITTER vs INPUT AMPLITUDE (4.25 Gbps, MAXIMUM BANDWIDTH) 0 8 −5 7 −10 6 Random Output Jitter − ps SDD11 − Differential Input Return Gain − dB G001 −15 −20 −25 −30 4 3 2 1 −35 −40 0.01 5 0 0.1 1 10 f − Frequency − GHz G003 Figure 7. 0 5 10 15 20 25 30 35 40 Differential Input Voltage − mVPP 45 50 G004 Figure 8. 11 ONET4291PA www.ti.com SLLS671 – SEPTEMBER 2005 TYPICAL CHARACTERISTICS (continued) Typical operating condition is at VCC = 3.3 V and TA = 25°C. BIT-ERROR RATIO vs INPUT AMPLITUDE (4.25 Gbps, MAXIMUM BANDWIDTH) LOS ASSERT/DEASSERT VOLTAGE vs DIGITAL CONTROL SETTING 100 100 90 LOS Assert/Deassert Voltage − mVP-P 10-2 Bit Error Ratio 10-4 10-6 10-8 10-10 10-12 10-14 80 70 60 50 40 30 20 LOS Deassert Voltage 10 LOS Assert Voltage 10-16 0.0 0.5 1.0 1.5 2.0 2.5 0 0x40 0x38 0x30 0x28 0x20 0x18 0x10 0x08 0x00 3.0 VID − Differential Input Voltage − mVP-P Register 5 Setting − Hex G006 G005 Figure 9. Figure 10. LOS ASSERT/DEASSERT VOLTAGE vs THRESHOLD RESISTANCE LOS HYSTERESIS vs DIGITAL CONTROL SETTING 55 6 5 45 40 LOS Hysteresis − dB LOS Assert/Deassert Voltage − mVPP 50 35 30 25 20 LOS Deassert Voltage 15 10 5 3 2 1 LOS Assert Voltage 0 0 0x40 0x38 0x30 0x28 0x20 0x18 0x10 0x08 0x00 12 16 20 24 28 32 36 40 44 48 52 56 60 RTH − Nominal Threshold Resistor − kΩ Figure 11. 12 4 G013 Register 5 Setting − Hex G007 Figure 12. ONET4291PA www.ti.com SLLS671 – SEPTEMBER 2005 TYPICAL CHARACTERISTICS (continued) Typical operating condition is at VCC = 3.3 V and TA = 25°C. LOS HYSTERESIS vs THRESHOLD RESISTANCE LOS THRESHOLD VARIATION OVER TEMPERATURE vs DIGITAL CONTROL SETTING 6 4.0 3.5 LOS Assert Voltage Variation − dB LOS Hysteresis − dB 5 4 3 2 1 3.0 2.5 2.0 1.5 1.0 0.5 0 0.0 0x40 0x38 0x30 0x28 0x20 0x18 0x10 0x08 0x00 12 16 20 24 28 32 36 40 44 48 52 56 60 RTH − Nominal Threshold Resistor − kΩ Register 5 Setting − Hex G014 G008 OUTPUT EYE DIAGRAM AT 4.25 Gbps AND MINIMUM INPUT VOLTAGE (5 mVp-p) (K28.5 PATTERN, MAXIMUM BANDWIDTH) OUTPUT EYE DIAGRAM AT 4.25 Gbps AND MAXIMUM INPUT VOLTAGE (2000 mVp-p) (K28.5 PATTERN, MAXIMUM BANDWIDTH) VOD − Differential Output Voltage − 160 mV/Div Figure 14. VOD − Differential Output Voltage − 160 mV/Div Figure 13. t − Time − 50 ps/Div t − Time − 50 ps/Div G009 Figure 15. G010 Figure 16. 13 ONET4291PA www.ti.com SLLS671 – SEPTEMBER 2005 TYPICAL CHARACTERISTICS (continued) Typical operating condition is at VCC = 3.3 V and TA = 25°C. OUTPUT EYE DIAGRAM AT 1.0625 Gbps AND MAXIMUM INPUT VOLTAGE (2000 mVp-p) (K28.5 PATTERN, REGISTER 4 SET TO 0x70) VOD − Differential Output Voltage − 160 mV/Div VOD − Differential Output Voltage − 160 mV/Div OUTPUT EYE DIAGRAM AT 1.0625 Gbps AND MINIMUM INPUT VOLTAGE (5 mVp-p) (K28.5 PATTERN, REGISTER 4 SET TO 0x70) t − Time − 200 ps/Div t − Time − 200 ps/Div G012 G011 Figure 17. 14 Figure 18. ONET4291PA www.ti.com SLLS671 – SEPTEMBER 2005 APPLICATION INFORMATION Figure 19 shows a typical application circuit using the ONET4291PA with a microprocessor for digital control of the LOS threshold, output amplitude, and bandwidth. SD SCK SDA To/From Microprocessor L1 BLM11HA102SG VCC R1 10 kΩ DIN+ DIN− DIN− C2 0.1 µF SD LOS C3 0.1 µF DOUT+ DOUT+ DOUT− DOUT− GND To/From SFP Connector C4 0.1 µF VCC DIN+ ONET4291PA 16-Pin QFN VCC From Transimpedance Amplifier (ROSA) COC− GND TH C1 0.1 µF COC+ RTHI C5 0.1 µF SCK SDA LOS C6 0.1 µF GND S0099-01 Figure 19. Basic Application Circuit With Digital Control 15 ONET4291PA www.ti.com SLLS671 – SEPTEMBER 2005 APPLICATION INFORMATION (continued) Figure 20 shows a typical application without digital control. In this case, the output amplitude and bandwidth are fixed. The LOS threshold is adjusted by means of a resistor connected to the TH terminal. L1 BLM11HA102SG VCC R1 10 kΩ DIN+ DIN− DIN− C2 0.1 µF SD LOS C3 0.1 µF DOUT+ DOUT+ DOUT− DOUT− GND To/From SFP Connector C4 0.1 µF VCC DIN+ ONET4291PA 16-Pin QFN VCC From Transimpedance Amplifier (ROSA) COC− GND TH C1 0.1 µF COC+ RTHI C5 0.1 µF SCK SDA LOS RTH 12 kΩ − 62 kΩ C6 0.1 µF GND S0099-02 Figure 20. Basic Application Circuit With External LOS Threshold Resistor 16 PACKAGE OPTION ADDENDUM www.ti.com 10-Dec-2020 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan (2) Lead finish/ Ball material MSL Peak Temp Op Temp (°C) Device Marking (3) (4/5) (6) ONET4291PARGVR ACTIVE VQFN RGV 16 2500 RoHS & Green NIPDAU Level-2-260C-1 YEAR -40 to 85 4291PA ONET4291PARGVT ACTIVE VQFN RGV 16 250 RoHS & Green NIPDAU Level-2-260C-1 YEAR -40 to 85 4291PA (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may reference these types of products as "Pb-Free". RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption. Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of