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