ADN2872

3.3 V Dual-Loop, 50 Mbps to 3.3 Gbps Laser Diode Driver ADN2872 FEATURES SFP/SFF and SFF-8472 MSA compliant SFP reference design available Any rate from 50 Mbps to 3.3 Gbps operation Dual-loop control of average power and extinction ratio Typical rise/fall time: 60 ps Bias current range: 2 mA to 100 mA Modulation current range: 5 mA to 90 mA Laser FAIL alarm and automatic laser shutdown (ALS) Bias and modulation current monitoring 3.3 V operation 4 mm × 4 mm LFCSP Voltage setpoint control Resistor setpoint control GENERAL DESCRIPTION Like the ADN2870, the ADN28721 laser diode driver is designed for advanced SFP and SFF modules, using SFF-8472 digital diagnostics. The device features dual-loop control of the average power and extinction ratio, which automatically compensates for variations in laser characteristics over temperature and aging. The laser needs only be calibrated at 25°C, eliminating the need for expensive and time consuming temperature calibration. The ADN2872 supports single-rate operation from 50 Mbps to 3.3 Gbps, or multirate operation from 155 Mbps to 3.3 Gbps. With a new alarm scheme, this device avoids the shutdown issue caused by the system transient generated from various lasers. The average power and extinction ratio can be set with a voltage provided by a microcontroller DAC or by a trimmable resistor. The part provides both bias and modulation current monitoring, as well as fail alarms and automatic laser shutdown. The ADN2872, a SFF-/SFP-compliant laser diode driver, can work with the Analog Devices, Inc., ADuC7019/ADuC702x MicroConverter® family and the ADN289x limiting amplifier family, to form a complete SFP/SFF transceiver solution. The ADN2872 is available in a space-saving 4 mm × 4 mm LFCSP specified over the −40°C to +85°C temperature range. Figure 1 shows an application diagram with a microcontroller interface. 1 APPLICATIONS Multirate OC3 to OC48-FEC SFP/SFF modules 1×/2×/4× Fibre Channel SFP/SFF modules LX-4 modules DWDM/CWDM SFP modules 1GE SFP/SFF transceiver modules Protected by U.S. Patent 6,414,974. APPLICATIONS DIAGRAM VCC VCC Tx_FAULT Tx_FAIL VCC MPD FAIL ALS IMODN VCC VCC L R IMODP DATAP ANALOG DEVICES MICROCONTROLLER DAC ADC PAVSET IMOD PAVREF CONTROL RPAV 1kΩ GND ERREF IBIAS CCBIAS IBIAS 100Ω DATAN VCC RZ LASER DAC ADN2872 1kΩ GND VCC GND GND 1kΩ GND 470Ω GND GND 08013-001 ERSET IBMON IMMON PAVCAP ERCAP Figure 1. Rev. 0 Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781.329.4700 www.analog.com Fax: 781.461.3113 ©2009 Analog Devices, Inc. All rights reserved. ADN2872 TABLE OF CONTENTS Features .............................................................................................. 1  Applications ....................................................................................... 1  General Description ......................................................................... 1  Applications Diagram ...................................................................... 1  Revision History ............................................................................... 2  Specifications..................................................................................... 3  SFP Timing Specifications........................................................... 4  Absolute Maximum Ratings............................................................ 5  ESD Caution .................................................................................. 5  Pin Configuration and Function Descriptions ............................. 6  Typical Performance Characteristics ............................................. 7  Optical Waveforms ........................................................................... 9  Theory of Operation ...................................................................... 10  Dual-Loop Control..................................................................... 10  Control ......................................................................................... 11  Voltage Setpoint Calibration ..................................................... 11  Resistor Setpoint Calibration .................................................... 13  IMPD Monitoring .......................................................................... 13  Loop Bandwidth Selection ........................................................ 14  Power Consumption .................................................................. 14  Automatic Laser Shutdown (Tx_Disable)............................... 14  Bias and Modulation Monitor Currents.................................. 14  IBIAS Pin ..................................................................................... 14  Data Inputs .................................................................................. 15  Laser Diode Interfacing ............................................................. 15  Alarms.......................................................................................... 16  Outline Dimensions ....................................................................... 17  Ordering Guide .......................................................................... 17  REVISION HISTORY 3/09—Revision 0: Initial Version Rev. 0 | Page 2 of 20 ADN2872 SPECIFICATIONS VCC = 3.0 V to 3.6 V. All specifications TMIN to TMAX, unless otherwise noted.1 Typical values as specified at 25°C. Table 1. Parameter LASER BIAS CURRENT (IBIAS) Output Current, IBIAS Compliance Voltage IBIAS when ALS High CCBIAS Compliance Voltage MODULATION CURRENT (IMODP, IMODN)2 Output Current, IMOD Compliance Voltage IMOD when ALS High Rise Time2, 3 Fall Time2, 3 Random Jitter2, 3 Deterministic Jitter2, 3 Pulse Width Distortion2, 3 AVERAGE POWER SET (PAVSET) Pin Capacitance Voltage Photodiode Monitor Current (Average Current) EXTINCTION RATIO SET INPUT (ERSET) Resistance Range Voltage AVERAGE POWER REFERENCE VOLTAGE INPUT (PAVREF) Voltage Range Photodiode Monitor Current (Average Current) EXTINCTION RATIO REFERENCE VOLTAGE INPUT (ERREF) Voltage Range DATA INPUTS (DATAP, DATAN)4 Input Voltage Swing (Differential) Input Impedance (Single-Ended) LOGIC INPUTS (ALS) VIH VIL ALARM OUTPUT (FAIL)5 VOFF VON IBMON, IMMON DIVISION RATIO IBIAS/IBMON3 IBIAS/IBMON3 IBIAS/IBMON Stability3, 6 IMOD/IMMON IBMON Compliance Voltage Min 2 1.2 1.2 5 1.5 60 60 0.8 90 VCC 0.05 104 96 1.1 35 30 80 1.35 1200 25 1.35 1 1000 1 2.4 50 2 0.8 >1.8 1.2 V Alarm if > 2.0 V Alarm if shorted to VCC (the alarm is valid for voltage setting mode only) Ignore Undervoltage or Short to GND Condition Ignore Alarm if < 0.4 V Alarm if shorted to GND Alarm if < 0.6 V Table 6. ADN2872 Response to Various Single-Point Faults in AC-Coupled Configuration, as Shown in Figure 32 Mnemonic CCBIAS PAVSET PAVREF RPAV Short to VCC Fault state occurs Fault state occurs Voltage mode: fault state occurs Resistor mode: tied to VCC Voltage mode: fault state occurs Resistor mode: tied to VCC Does not increase laser average power Fault state occurs Does not increase laser average power Does not increase laser average power Output currents shut off Does not increase laser average power Does not affect laser power Voltage mode: fault state occurs Resistor mode: tied to VCC Fault state occurs Fault state occurs Does not increase laser average power Does not increase laser average power Fault state occurs Short to GND Fault state occurs Fault state occurs Fault state occurs Fault state occurs Open Does not increase laser average power Fault state occurs Fault state occurs Voltage mode: fault state occurs Resistor mode: does not increase average power Does not increase laser average power Fault state occurs Does not increase laser average power Does not increase laser average power Output currents shut off Does not increase laser average power Does not increase laser average power Does not increase laser average power ERCAP PAVCAP DATAP DATAN ALS ERSET IMMON ERREF IBMON FAIL IMODP IMODN IBIAS Does not increase laser average power Fault state occurs Does not increase laser average power Does not increase laser average power Normal currents Does not increase laser average power Does not increase laser average power Voltage mode: does not increase average power Resistor mode: fault state occurs Does not increase laser average power Does not increase laser average power Does not increase laser average power Does not increase laser average power Fault state occurs Does not increase laser average power Does not increase laser average power Does not increase laser average power Does not increase laser power Fault state occurs Rev. 0 | Page 16 of 20 ADN2872 OUTLINE DIMENSIONS 0.60 MAX 0.60 MAX 19 18 EXPOSED PAD (BO OMVIEW) TT 4.00 BSC SQ PIN 1 INDICATOR 24 1 PIN 1 INDICATOR TOP VIEW 3.75 BSC SQ 0.50 BSC 0.50 0.40 0.30 *2.45 2.30 SQ 2.15 6 13 12 7 0.23 MIN 2.50 REF 1.00 0.85 0.80 12° MAX 0.80 MAX 0.65 TYP 0.05 MAX 0.02 NOM 0.30 0.23 0.18 0.20 REF COPLANARITY 0.08 SEATING PLANE FOR PROPER CONNECTION OF THE EXPOSED PAD, REFER TO THE PIN CONFIGURATION AND FUNCTION DESCRIPTIONS SECTION OF THIS DATA SHEET. 080808-A *COMPLIANT TO JEDEC STANDARDS MO-220-VGGD-2 EXCEPT FOR EXPOSED PAD DIMENSION Figure 34. 24-Lead Lead Frame Chip Scale Package [LFCSP_VQ] 4 mm × 4 mm Body, Very Thin Quad (CP-24-2) Dimensions shown in millimeters ORDERING GUIDE Model ADN2872ACPZ1 ADN2872ACPZ-RL1 ADN2872ACPZ-R71 1 Temperature Range −40°C to +85°C −40°C to +85°C −40°C to +85°C Package Description 24-Lead LFCSP_VQ 24-Lead LFCSP_VQ 24-Lead LFCSP_VQ Package Option CP-24-2 CP-24-2 CP-24-2 Ordering Quantity 490 5,000 1,500 Z = RoHS Compliant Part. Rev. 0 | Page 17 of 20 ADN2872 NOTES Rev. 0 | Page 18 of 20 ADN2872 NOTES Rev. 0 | Page 19 of 20 ADN2872 NOTES ©2009 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D08013-0-3/09(0) Rev. 0 | Page 20 of 20