GENERAL DESCRIPTION
The ADN2871 laser diode driver is designed for advanced SFP and SFF modules, using SFF-8472 digital diagnostics. The ADN2871 supports operation from 50 Mbps to 4.25 Gbps.
Average power and extinction ratio can be set with a voltage provided by a microcontroller DAC or by a trimmable resistor or digital potentiometer. The average power control loop is implemented using feedback from a monitor photodiode. The part provides bias and modulation current monitoring as well as fail alarms and automatic laser shutdown (ALS). The device interfaces easily with the Analog Devices, Inc. ADuC70xx family of MicroConverters® and with the ADN289x family of limiting amplifiers to make a complete SFP/SFF transceiver solution. An SFP reference design is available. The product is pin-compatible with the ADN2870 dual-loop LDD, allowing one PC board layout to work with either device. For dual-loop applications, refer to the ADN2870 data sheet.
The product 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 of the voltage setpoint control with single-ended laser interface. Figure 36 shows a differential laser interface.

FEATURES
  SFP/SFF and SFF-8472 MSA-compliant
  SFP reference design available
  50 Mbps to 4.25 Gbps operation
  Automatic average power control
  Typical rise/fall time 60 ps
  Supports VCSEL, DFB, and FP lasers
  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
  Pin-compatible with ADN2870
 
APPLICATIONS
  1×/2×/4× Fibre Channel SFP/SFF modules
  Multirate OC3 to OC48-FEC SFP/SFF modules
  LX-4 modules
  DWDM/CWDM SFP modules
  1GE SFP/SFF transceiver modules
  VCSEL, DFB, and FP transmitters