Dual-Loop, 50 Mbps to 2.7 Gbps

Laser Diode Driver

Data Sheet

ADN2841

Rev. B

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FEATURES

50 Mbps to 2.7 Gbps operation

Typical rise/fall time: 80 ps

Bias current range: 2 mA to 100 mA

Modulation current range: 5 mA to 80 mA

Monitor photodiode current: 50 µA to 1200 µA

Closed-loop control of power and extinction ratio

Laser fail and laser degrade alarms

Automatic laser shutdown (ALS)

Dual MPD functionality for DWDM

Optional clocked data

Full current parameter monitoring

5 V operation

48-lead LFCSP

32-lead LFCSP (reduced functionality)

APPLICATIONS

DWDM dual MPD wavelength fixing

SONET OC-1/3/12/48

SDH STM-1/4/16

Fibre Channel

Gigabit Ethernet

GENERAL DESCRIPTION

The ADN2841 uses a unique control algorithm to control both

the average power and extinction ratio of the laser diode (LD)

after initial factory setup. Because power and extinction ratio

control are fully integrated, external component count is low

and PCB area is small. Programmable alarms are provided for

laser fail (end of life) and laser degrade (impending fail).

The ADN2841 has circuitry for a second monitor photodiode,

which enables DWDM wavelength control.

FUNCTIONAL BLOCK DIAGRAM

CONTROL

DATAP

DATAN

CLKP

CLKN

IMODP

LD

GND

ASET

GND

GND

GND

GND

GND

LBWSET

IDTONE

PAVCAP

ERCAP

ERSET

PSET

IMPD2

IMPD

MPD

ADN2841

IMODN

IBIAS

Figure 1.