XRT91L33IG-F

XRT91L33 STS-12/STS-3 MULTIRATE CLOCK AND DATA RECOVERY UNIT AUG 2008 REV. V1.0.0 FEATURES • Performs clock and data recovery for selectable data of 622.08 Mbps (STS-12/STM-4) or 155.52 Mbps (STS-3/STM-1) NRZ data • Meets Telcordia, ANSI and ITU-T G.783 and G.825 SDH jitter requirements including T1.105.03 - 2002 SONET Jitter Tolerance specification, and GR-253 CORE, GR-253 ILR SONET Jitter specifications. • Lock output pin monitors data run length and frequency drift from reference clock • Data is resampled at the output • Active High Signal Detect (SIGD) LVPECL input • Low jitter, high-speed outputs support LVPECL and low-power LVDS termination • 19.44 MHz reference frequency LVTTL input • Low power: 215 mW typical • 3.3V power supply • 20-pin TSSOP package • Requires one external capacitor • PLL bypass operation facilitates board debug process APPLICATIONS • SONET/SDH-based Transmission Systems • Add/Drop Multiplexers • Cross Connect Equipment • ATM and Multi-Service Switches, Routers and Switch/Routers • DSLAMS • SONET/SDH Test Equipment • DWDM Termination Equipment GENERAL DESCRIPTION The XRT91L33 is a fully integrated multirate Clock and Data Recovery (CDR) device for SONET/SDH 622.08 Mbps STS-12/STM-4 or 155.52 Mbps STS-3/ STM-1 applications. The device provides Clock and Data Recovery (CDR) function by synchronizing its on-chip Voltage Controlled Oscillator (VCO) to the incoming serial scrambled non-return to zero (NRZ) data stream. Figure 1 shows the block diagram of the XRT91L33. • ESD greater than 2kV on all pins FIGURE 1. BLOCK DIAGRAM OF XRT91L33 STS12_MODE REFCK 19.44 MHz CAP+ 1u F CAP+ PLL RX LOOP FILTER TEST Differential Receiver RECVDDATAOUT RXDIP RXDATAIN RXDIN External 100R termination Internal biasing 0 CDR STS-12/3 or STM-4/1 Clock and Data Recovery LVDS/LVPECL Output Drivers RXDOP RXDON 1 RECVDCLKOUT RXCLKOP RXCLKON LOCK LCKTOREFN SIGD MUTE RXDO Exar Corporation 48720 Kato Road, Fremont CA, 94538 • (510) 668-7000 • FAX (510) 668-7017 • www.exar.com XRT91L33 STS-12/STS-3 MULTIRATE CLOCK AND DATA RECOVERY UNIT REV. V1.0.0 CLOCK AND DATA RECOVERY OVERVIEW The clock and data recovery (CDR) unit accepts high speed NRZ serial data from the Differential receiver and generates a clock with a frequency equal to that of the incoming data. The CDR block uses a reference clock to train and monitor its clock recovery PLL. Upon startup, the PLL locks to the local reference clock. Once this is achieved, the PLL attempts to lock onto the incoming receive serial data stream. Whenever the recovered clock frequency deviates from the local reference clock frequency by more than approximately ±500 ppm, the clock recovery PLL will switch and lock back onto the local reference clock and declare a Loss of Lock. Whenever a Loss of Lock or a Loss of Signal event occurs, the CDR will continue to supply a recovered clock (based on the local reference) to the framer/mapper device. An LOS condition occurs when either SIGD or LCKTOREFN is low. In this case, the receive serial data output is forced to a logic zero state for the entire duration of the LOS condition. This acts as a receive data mute upon LOS function to prevent random noise from being misinterpreted as valid incoming data. When SIGD becomes active again, the recovered clock is determined to be within ±500 ppm accuracy with respect to the local reference source and LOS is no longer declared, the clock recovery PLL will switch and lock back onto the incoming receive serial data stream. FIGURE 2. 20 PIN TSSOP OF XRT91L33 (TOP VIEW) 1 VDDA VDDA 20 2 RXDIP VSSA 19 3 RXDIN CAP+ 18 4 VSSA CAP- 17 5 LOCK TEST 16 6 STS12_MODE SIGD 15 7 REFCK RXDOP 14 8 LCKTOREFN RXDON 13 9 VSS RXCLKOP 12 10 VDD RXCLKON 11 TABLE 1: ORDERING INFORMATION PART NUMBER PACKAGE OPERATING TEMPERATURE RANGE XRT91L33IG 20-pin TSSOP Package -40°C to +85°C XRT91L33IG-F 20-Pin TSSOP Lead-Free Package -40°C to +85°C 2 XRT91L33 REV. V1.0.0 STS-12/STS-3 MULTIRATE CLOCK AND DATA RECOVERY UNIT FEATURES......................................................................................................................... 1 APPLICATIONS ................................................................................................................. 1 GENERAL DESCRIPTION................................................................................................. 1 FIGURE 1. BLOCK DIAGRAM OF XRT91L33 ...................................................................................................................................... 1 CLOCK AND DATA RECOVERY OVERVIEW ....................................................................................................... 2 FIGURE 2. 20 PIN TSSOP OF XRT91L33 (TOP VIEW) .................................................................................................................... 2 TABLE 1: ORDERING INFORMATION ................................................................................................................................................... 2 1.0 PIN DESCRIPTIONS .............................................................................................................................. 4 TABLE 2: PIN DESCRIPTION TABLE ................................................................................................................................................... 4 ..................................................................................................................................................................... 5 2.0 FUNCTIONAL DESCRIPTION ............................................................................................................... 6 2.1 2.2 2.3 2.4 2.5 REFERENCE CLOCK INPUT ........................................................................................................................... RECEIVE CLOCK AND DATA RECOVERY .................................................................................................... EXTERNAL RECEIVE LOOP FILTER CAPACITOR ....................................................................................... STS-12/STM-4 AND STS-3/STM-1 MODE OF OPERATION ........................................................................... SIGNAL DETECTION ....................................................................................................................................... 6 6 6 6 6 FIGURE 3. CONTROL DIAGRAM FOR SIGNAL DETECTION CIRCUIT AND PLL TEST OPERATION ............................................................ 7 2.6 LOCK DETECTION ........................................................................................................................................... 7 2.7 PLL TEST OPERATION ................................................................................................................................... 7 TABLE 3: SIGNAL DETECT AND PLL TEST OPERATION CONTROL .................................................................................................... 8 3.0 ELECTRICAL CHARACTERISTICS ..................................................................................................... 9 3.1 ABSOLUTE MAXIMUM RATINGS ................................................................................................................... 9 TABLE 4: ABSOLUTE MAXIMUM RATINGS........................................................................................................................................... 9 3.2 OPERATING CONDITIONS .............................................................................................................................. 9 TABLE 5: RECOMMENDED OPERATING CONDITIONS .......................................................................................................................... 9 3.3 LVPECL SINGLE ENDED INPUT AND OUTPUT DC CHARACTERISTICS .................................................. 9 TABLE 6: LVPECL SINGLE ENDED INPUTS AND OUTPUTS ................................................................................................................. 9 3.4 LVPECL DIFFERENTIAL INPUT AND OUTPUT DC CHARACTERISTICS ................................................. 10 TABLE 7: LVPECL DIFFERENTIAL INPUTS AND OUPUTS .................................................................................................................. 10 FIGURE 4. DIFFERENTIAL VOLTAGE SWING DEFINITIONS (INPUT OR OUTPUT) FOR CLOCK AND DATA ................................................... 10 TABLE 8: LVDS OUTPUTS............................................................................................................................................................. 10 TABLE 9: LVTTL INPUTS ................................................................................................................................................................ 11 3.5 AC CHARACTERISTICS ................................................................................................................................ 11 TABLE 10: PERFORMANCE SPECIFICATIONS .................................................................................................................................... 11 4.0 JITTER PERFORMANCE .................................................................................................................... 12 4.1 SONET JITTER REQUIREMENTS ................................................................................................................. 12 4.1.1 RX JITTER TOLERANCE: .......................................................................................................................................... 12 FIGURE 5. GR-253/G.783 JITTER TOLERANCE MASK ..................................................................................................................... 12 FIGURE 6. XRT91L33 JITTER TOLERANCE AT 155 MBPS OC3/STM-1.......................................................................................... 13 FIGURE 7. XRT91L33 JITTER TOLERANCE AT 622 MBPS OC12/STM-4........................................................................................ 13 4.1.2 JITTER GENERATION................................................................................................................................................ 13 5.0 HIGH-SPEED OUTPUTS ..................................................................................................................... 14 FIGURE 8. HIGH SPEED OUTPUTS, LVDS TERMINATION.................................................................................................................. 14 FIGURE 9. HIGH-SPEED OUTPUTS, LVPECL TERMINATION OPTIONS ............................................................................................... 14 6.0 RESAMPLED DATA AND CLOCK OUTPUTS .................................................................................. 15 FIGURE 10. OUTPUT DATA AND CLOCK AFTER RESAMPLING............................................................................................................ 15 TABLE 11: OUTPUT TIMING ............................................................................................................................................................ 15 7.0 PACKAGE DIMENSIONS .................................................................................................................... 16 TABLE 12: REVISION HISTORY ........................................................................................................................................................ 16 3 XRT91L33 STS-12/STS-3 MULTIRATE CLOCK AND DATA RECOVERY UNIT REV. V1.0.0 1.0 PIN DESCRIPTIONS TABLE 2: PIN DESCRIPTION TABLE NAME LEVEL TYPE PIN DESCRIPTION VDDA PWR PWR 1 3.3V Power supply RXDIP LVDS/PECL I 2 Positive side of receive data input. The high-speed output clock (RXCLKOP/N) is recovered from this high-speed differential inupt data. RXDIN LVDS/PECL I 3 Negative side of receive data input. The high-speed output clock (RXCLKOP/N) is recovered from this high-speed differential input data. VSSA PWR PWR 4 Ground pin LOCK LVPECL O 5 Active HIGH to indicate that the PLL is locked to serial data input and valid clock and data are present at the serial outputs (RXDOP/N and RXCLKOP/N). The LOCK will go inactive under the following conditions: • If SIGD is set LOW • If LCKTOREFN is set LOW • If the VCO has drifted away from the local reference clock, REFCK, by more than +/- 500 ppm STS12_MODE LVTTL I 6 STS-12 or STS-3 mode selection. Set HIGH to select the STS-12 operation. Set LOW for STS-3 operation REFCK LVTTL I 7 Local 19.44 MHz reference clock input for the CDR. REFCK is used for the PLL phase adjustment during power up. It also serves as a stable clock source in the absence of serial input data. LCKTOREFN LVTTL I 8 Lock to REFCK input. When set LOW, this pin causes the output clock, RXCLKOP/N to be held within +/- 500ppm of the input reference clock REFCL and forces the RXDOP/N to a low state. VSS PWR PWR 9 Ground pin VDD PWR PWR 10 3.3V power supply RXCLKON LVDS/ LVPECL O 11 High-speed clock output, negative. This clock is recovered from the receive data input (RXDIP/N) and supports either LVDS or LVPECL termination RXCLKOP LVDS/ LVPECL O 12 High-speed clock output, positive This clock is recovered from the receive data input (RXDIP/N) and supports either LVDS or LVPECL. termination RXDON LVDS/ LVPECL O 13 High-speed output, negative This is the retimed version of the recovered data stream from RXDIP/N and can be in either LVDS or LVPECL termination RXDOP LVDS/ LVPECL O 14 High-speed output, positive. This is the retimed version of the recovered data stream from RXDIP/N and can be in either LVDS or LVPECL termination 4 XRT91L33 STS-12/STS-3 MULTIRATE CLOCK AND DATA RECOVERY UNIT REV. V1.0.0 NAME LEVEL TYPE PIN DESCRIPTION SIGD LVPECL I 15 Signal detect. SIGD should be connected to the SIGD output on the optical module. SIGD is active HIGH. When SIGD is set HIGH, it means there is sufficient optical power. When SIGD is LOW, this indicates an LOS condition, the RXCLKOP/N output signal will be held to within +/- 500 ppm of the REFCK input. Additionally, the RXDOP/N will be held in the LOW state. TEST LVTTL I 16 Used for production testing. Set to VSS for normal operation. CAP- Analog I 17 Negative side of the external loop filter. The loop filter capacitor should be connected to these pins. The capacitor value should be 1.0 μF +/- 10 % CAP+ Analog I 18 Positive side of the external loop filter. The loop filter capacitor should be connected to these pins. The capacitor value should be 1.0 μF +/- 10 %. VSSA PWR PWR 19 Ground pin VDDA PWR PWR 20 3.3V power supply 5 XRT91L33 STS-12/STS-3 MULTIRATE CLOCK AND DATA RECOVERY UNIT REV. V1.0.0 2.0 FUNCTIONAL DESCRIPTION The XRT91L33 CDR is designed to operate with a SONET Framer/ASIC device and provide a high-speed serial clock and data recovery interface to optical networks. The CDR receives a differential NRZ serial bit stream running at STS-12/STM-4 or STS-3/STM-1 and generates recovered serial clock and data via differential LVDS/LVPECL drivers. 2.1 Reference Clock Input The XRT91L33 accepts a 19.44 MHz LVTTL clock input at REFCK. The REFCK should be generated from a source that has a frequency accuracy better than ±100ppm in order for the CDR Loss of Lock detector to have the necessary accuracy required for SONET systems. 2.2 Receive Clock and Data Recovery The clock and data recovery (CDR) unit accepts the high-speed NRZ serial data from the Differential receiver and generates a clock that is the same frequency as the incoming data. The clock recovery block utilizes the reference clock from REFCK to train and monitor its clock recovery PLL. Upon startup, the PLL locks to the local reference clock. Once this is achieved, the PLL then attempts to lock onto the incoming receive serial data stream. Whenever the recovered clock frequency deviates from the local reference clock frequency by more than approximately ±500ppm, the clock recovery PLL will switch to the local reference clock, declare a Loss of Lock and output a LOW level signal on the LOCK output pin. Whenever a Loss of Lock (LOL) or a Loss of Signal (LOS) event occurs, the CDR will continue to supply a receive clock (based on the local reference). 2.3 External Receive Loop Filter Capacitor For STS12/STM4 and STS3/STM1 operation, the XRT91L33 uses a 1.0uF (or greater) external loop filter capacitor to achieve the required receiver jitter performance. It must be well isolated to prohibit noise entering the CDR block and should be placed as close to the pins as possible. The non-polarized capacitor should be of ±10% tolerance. Use type X7R or X5R capacitors for improved stability over temperature. 2.4 STS-12/STM-4 and STS-3/STM-1 Mode of Operation The VCO output signal is fed into a programmable frequency divider allowing to properly set the PLL operating frequency corresponding to the desired data rate. For 622.08 Mbps signal STS12_MODE is set HIGH and for 155.52 Mbps, STS12_MODE is set LOW. 2.5 Signal Detection XRT91L33 has two control pins that are used to indicate an LOS condition (Loss Of Signal). The SIGD pin is a LVPECL input and the LCKTOREFN pin is a LVTTL input. They are internally connected as shown in Figure 3. If either of these two inputs goes LOW and TEST is LOW, XRT91L33 will enter a Loss of Signal (LOS) state, and will mute the RXDOP/N. During the LOS state, XRT91L33 will also maintain RXCLKOP/N within ±500ppm of the input reference clock, REFCK. Most optical modules have an SIGD output. This SIGD output indicates that there is sufficient optical power and is typically active HIGH. If the SIGD output on the optical module is LVPECL, it should be connected directly to the SIGD input of XRT91L33, and the LCKTOREFN input should be tied HIGH. If the SIGD output is LVTTL, it should be connected directly to the LCKTOREFN input and the SIGD input should be tied HIGH. The SIGD and LCKTOREFN inputs also can be used for other applications when it is required to hold RXCLKOP/N output within ±500ppm of the input reference clock and mute the serial data output lines. 6 XRT91L33 STS-12/STS-3 MULTIRATE CLOCK AND DATA RECOVERY UNIT REV. V1.0.0 FIGURE 3. CONTROL DIAGRAM FOR SIGNAL DETECTION CIRCUIT AND PLL TEST OPERATION RXDIP/N PLL Clock (Internal) REFCK 2 2 RXDOP/N 0 2 RXCLKOP/N 1 STS12_MODE TEST LOS (Internal) LCKTOREFN SIGD 2.6 Lock Detection XRT91L33 features a PLL lock detection circuit. The lock detect (LOCK) output goes HIGH to indicate that the PLL is locked to the serial data input and valid data and clock are present at the high-speed differential output. The LOCK output will go LOW if either the LOCKTOREFN or the SIGD input is forced LOW. Additionally, LOCK will also go low if the incoming data frequency is more than +/-500ppm away from the reference clock frequency (REFCK x 32 in OC12 mode, REFCLK x 8 in OC3 mode). When LOCK output is driven LOW, the VCO is forced to lock to REFCK and then released to lock on the incoming data. If the incoming data frequency remains outside the +/-500ppm window, the training mode is repeated. Debounce logic stabilizes the LOCK output pin to stay LOW for incoming frequencies well beyond the +/-500ppm window. 2.7 PLL Test Operation The TEST pin is intended for use in production test and should be set at logic LOW in normal operation. If both TEST and STS12_MODE pins are set to logic HIGH, XRT91L33 will bypass the PLL and present an inverted version of the REFCK to the clock output RXCLKOP/N. REFCK’s rising edge is used to capture the input data and transmit data to RXDOP/N. This bypass test operation can be used to facilitate board level debugging process. 7 XRT91L33 STS-12/STS-3 MULTIRATE CLOCK AND DATA RECOVERY UNIT REV. V1.0.0 . TABLE 3: SIGNAL DETECT AND PLL TEST OPERATION CONTROL STS12_MODE TEST LCKTOREFN SIGD RXDO RXCLKO 1 0 1 1 RXDI PLL clock 1 0 1 0 Muted PLL clock 1 0 0 1 Muted PLL clock 1 0 0 0 Muted PLL clock 1 1 X X RXDI REFCK 0 0 1 1 RXDI PLL clock 0 0 1 0 Muted PLL clock 0 0 0 1 Muted PLL clock 0 0 0 0 Muted PLL clock 0 1 X X Not allowed Not allowed 8 XRT91L33 STS-12/STS-3 MULTIRATE CLOCK AND DATA RECOVERY UNIT REV. V1.0.0 3.0 ELECTRICAL CHARACTERISTICS 3.1 Absolute Maximum RATINGS TABLE 4: ABSOLUTE MAXIMUM RATINGS SYMBOL VDD TS VESD 3.2 PARAMETER MINIMUM MAXIMUM UNIT Power supply voltage, referenced to GND -0.5 4.0 V DC input voltage (LVPECL, LVTTL) -0.5 VDD+0.5 V Output current (LVDS or LVPECL) -50 +50 mA Storage Temperature -65 150 °C -2000 2000 V Electrostatic discharge voltage, human body model Operating Conditions TABLE 5: RECOMMENDED OPERATING CONDITIONS SYMBOL VDD Temp PARAMETER Power supply voltage MIN. TYP MAX. UNITS 3.135 3.3 3.465 V 85 °C -40 Operating Temperature under bias 1 IDD Power supply current (outputs unterminated) 65 80 mA PD Power dissipation (outputs unterminated) 215 277 mW 1. Lower limit of specification is ambient temperature, and upper limit is case temperature. 3.3 LVPECL Single Ended Input and Output DC characteristics TABLE 6: LVPECL SINGLE ENDED INPUTS AND OUTPUTS SYMBOL PARAMETER MIN. TYP. MAX. UNITS CONDITIONS VIH Input HIGH voltage VDD-1.125 VDD-0.5 V Guaranteed input HIGH voltage VIL Input LOW voltage VDD-2.0 VDD-1.5 V Guaranteed input LOW voltage IIH Input HIGH current -0.5 10 μA VIN = VDD - 0.5V IIL Input LOW current -0.5 10 μA VIN=VDD-2.0V VOL Output LOW voltage VDD-2.0 VDD-1.8 V 50 Ω to (VDD-2.0V) VOH Output HIGH voltage VDD-1.25 VDD-0.67 V 50 Ω to (VDD-2.0V) 9 XRT91L33 STS-12/STS-3 MULTIRATE CLOCK AND DATA RECOVERY UNIT 3.4 REV. V1.0.0 LVPECL Differential Input and Output DC characteristics TABLE 7: LVPECL DIFFERENTIAL INPUTS AND OUPUTS SYMBOL PARAMETER MIN. TYP. MAX. UNITS CONDITIONS VIH Input HIGH voltage VDD-1.75 VDD-0.4 V Guaranteed input HIGH voltage VIL Input LOW voltage VDD-2.0 VDD-0.7 V Guaranteed input LOW voltage IIH Input HIGH current -0.5 10 μA VIN DIFF =0.5V IIL Input LOW current -0.5 10 μA VIN DIFF =0.5V VIDIFF Input PECL Differential Voltage, peakto-peak swing (see Figure 4) 250 VOCM Output Common-Mode Voltage 0.8 VODIFF Output LVPECL Differential Voltage, peak-to-peak swing (see Figure 4) 800 mV 1.35 1.7 V 50 Ω to (VDD-2.0V) 1700 mV 50 Ω to (VDD-2.0V) FIGURE 4. DIFFERENTIAL VOLTAGE SWING DEFINITIONS (INPUT OR OUTPUT) FOR CLOCK AND DATA V(+) V SING LE V(-) V DIFF = V(+)-V(-) 2 x V SINGLE 0V TABLE 8: LVDS OUTPUTS SYMBOL PARAMETER MIN. TYP. MAX. UNITS CONDITIONS 1.35 1.7 V 100 Ω between RXDOP/N and RXCLKP/N 1700 mV 100 Ω between RXDOP/N and RXCLKP/N VOCM Output common-mode voltage 1.0 VODIFF Output LVDS Differential Voltage, peak-to-peak Swing (see Figure 4) 700 10 XRT91L33 STS-12/STS-3 MULTIRATE CLOCK AND DATA RECOVERY UNIT REV. V1.0.0 TABLE 9: LVTTL INPUTS SYMBOL PARAMETER MIN. TYP. MAX. UNITS CONDITIONS VIH Input HIGH voltage 2.0 VDD V VIL Input LOW voltage 0 0.8 V IIH Input HIGH current -50 50 μA VIN = 2.75 V, VDD = Maximum IIL Input LOW current -50 50 μA VIN = 0.5 V, VDD = Maximum 3.5 AC Characteristics TABLE 10: PERFORMANCE SPECIFICATIONS Test Condition: VDD = 3.3V + 5% unless otherwise specified SYMBOL f fTOL fTREF_CLK PARAMETER MIN VCO center frequency TYP MAX 622.08 UNITS CONDITIONS MHz CDR’s reference clock frequency -250 250 ppm OC-12/STS-12 capture range -500 500 ppm with respect to the fixed reference frequency 45 55 % UI 20% minimum transition density CLKOUTDC Clock output duty cycle tLOCK OC-12/STS-12 acquisition lock time 16 μs Valid REFCK and device already powered up tLOCK_R, tLOCK_F LOCK output rise and fall time 500 ps 10% to 90%, with 100 Ω and 5 pF capacitive equivalent load JGEN_CLCK RXCLKOP/N iitter generation 0.01 UIrms JTOL OC-12/STS-12 jitter tolerance 0.005 0.40 11 0.5 UI Sinusoidal input jitter of RXDIP/N from 250 KHz to 5MHz XRT91L33 STS-12/STS-3 MULTIRATE CLOCK AND DATA RECOVERY UNIT REV. V1.0.0 4.0 JITTER PERFORMANCE 4.1 SONET Jitter Requirements SONET receive equipment jitter requirements are specified jitter tolerance and jitter transfer. The definitions of each of these types of jitter are given below. 4.1.1 Rx Jitter Tolerance: OC-3/STM-1, and OC-12/STM-4 category II SONET interfaces should tolerate, the input jitter applied according to the mask of Figure 6, with the corresponding specified parameters. Jitter measurements are done with standard SONET/SDH testers such as Acterna ANT20 as well as Agilent Omniber testers. FIGURE 5. GR-253/G.783 JITTER TOLERANCE MASK A3 slope= -20dB/decade Input Jitter Amplitude (UIpp) A2 slope= -20dB/decade A1 f0 f1 f2 f4 f3 Jitter Frequency (Hz) OC-N F0 (HZ) F1 (HZ) F2 (HZ) F3 (HZ) F4 (HZ) A1 (UIPP) A2 (UIPP) A3 (UIPP) OC1/STS11 STM-X LEVEL STM0 10 30 300 2K 20K 0.15 1.5 15 OC3/STS33 STM1 10 30 300 6.5K 65K 0.15 1.5 15 OC12/STS12 STM4 12 10 30 300 25K 250K 0.15 1.5 15 12 XRT91L33 STS-12/STS-3 MULTIRATE CLOCK AND DATA RECOVERY UNIT FIGURE 6. XRT91L33 JITTER TOLERANCE AT 155 MBPS OC3/STM-1 XRT 91L33 Jitter Tolerance OC3 100.00 Jitter (UI) 10.00 1.00 0.10 0.01 0.10 1.00 10.00 100.00 Frequency (KHz) 1,000.00 10,000.00 Jitter Mask FIGURE 7. XRT91L33 JITTER TOLERANCE AT 622 MBPS OC12/STM-4 XRT 91L33 Jitter Tolerance OC12 1,000.00 Jitter (UI) 100.00 10.00 1.00 0.10 0.01 4.1.2 0.10 1.00 10.00 100.00 Frequency (KHz) 1,000.00 10,000.00 Jitter Mask Jitter Generation Maximum jitter generation is less than 0.01 UI rms within the SONET/SDH band, when rms jitter of less than 14 ps (OC-12) or 56 ps (OC-3) is presented to the serial data inputs. 13 XRT91L33 STS-12/STS-3 MULTIRATE CLOCK AND DATA RECOVERY UNIT REV. V1.0.0 5.0 HIGH-SPEED OUTPUTS The high-speed output buffers, RXDOP/N and RXCLKOP/N can be terminated as either LVDS or LVPECL outputs. In LVDS mode, the transmission lines must be routed with 100 Ω differential impedance and terminated at the receive end with a line-to-line 100 Ω resistor (See Figure 8). FIGURE 8. HIGH SPEED OUTPUTS, LVDS TERMINATION XRT91L33 100 Ohm Receiver For LVPECL conections, the transmission line must be terminated with 50 Ω pull-down resistors near the receiving end or an equivalent circuit. (See Figure 9) FIGURE 9. HIGH-SPEED OUTPUTS, LVPECL TERMINATION OPTIONS 50 Ohm V DD – 2.0V Receiver 50 Ohm XRT91L33 V DD – 2.0V Creates 2V bias when V DD = 3.3V 82 Ohm V DD V DD 124 Ohm 168 Ohm V SS Receiver 82 Ohm 168 Ohm 124 Ohm XRT91L33 (Unbiased and No internal termination) V SS XRT91L33 168 Ohm 168 Ohm Receiver (Baised with internal termination) 14 XRT91L33 STS-12/STS-3 MULTIRATE CLOCK AND DATA RECOVERY UNIT 6.0 RESAMPLED DATA AND CLOCK OUTPUTS It is recommended that the retimed data output be captured with the rising edge of the clock output as shown in Figure 10. Data valid time is longer for OC-3/STS-3 mode of operation than that of OC-12/STS-12. Data valid time before the output clock’s rising edge is the available setup time (tSU), while the data valid time after the clock’s rising edge is the available hold time (tH). FIGURE 10. OUTPUT DATA AND CLOCK AFTER RESAMPLING RXDOP/N RXCLKOP/N tH tSU TABLE 11: OUTPUT TIMING SYMBOL tSU tH PARAMETER Available setup time Available hold time MINIMUM MAXIMUM UNIT CONDITION 450 ps STS-12 operation (622.08 MHz) 2.0 ns STS-3 operation (155.52 MHz) 650 ps STS-12 operation (622.08 MHz) 3.0 ns STS-3 operation (155.52 MHz) 15 XRT91L33 STS-12/STS-3 MULTIRATE CLOCK AND DATA RECOVERY UNIT 7.0 PACKAGE DIMENSIONS 20 pin Surface mount TSSOP TABLE 12: REVISION HISTORY REVISION # DATE V1.0.0 Aug 2008 DESCRIPTION Product Release Datasheet 16 REV. V1.0.0