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ADN2830

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REV.

REV.

Continuous Wave Laser

FUNCTIONAL BLOCK DIAGRAM

GND

GND

PAVCAP

MPD

IBMON

IMPDMON

ALS

FAIL

DEGRADE

GND

CONTROL

GND

IMPD

IBIAS

GND

RASET

MODE

LD

PSET

ASET

FEATURES

Bias Current Range 4 mA to 200 mA

Monitor Photodiode Current 50

A to 1200

A

Closed-Loop Control of Average Power

Laser FAIL and Laser DEGRADE Alarms

Automatic Laser Shutdown, ALS

Full Current Parameter Monitoring

5 V Operation

–40 C to +85 C Temperature Range

5 mm

5 mm 32-Lead LFCSP Package

APPLICATIONS

Fiber Optic Communication

GENERAL DESCRIPTION

The ADN2830 provides closed-loop control of the average

optical power of a continuous wave (CW) laser diode (LD)

after initial factory setup. The control loop adjusts the laser

IBIAS to maintain a constant back facet monitor photodiode

(MPD) current and thus a constant laser optical power. The

external PSET resistor is adjusted during factory setup to set

is the MPD current corresponding to the desired optical power.

Programmable alarms are provided for laser fail (end of life)

and laser degrade (impending fail).

To provide monitoring of the MPD current, the MPD can be

connected to the IMPD pin. In this case, the MPD current is

mirrored to the IMPDMON pin to provide a monitor and

internally to the PSET pin to close the control loop.

By closing the feedback using IBMON rather than an MPD

connected to PSET, the device is configured to control a constant

current in the laser rather than a constant optical output power.

Average Power Controller

B

781/461-3113

2012