iC-WJB

2.7 V LASER DIODE DRIVER

Rev E1, Page 2/12

DESCRIPTION

The iC-WJB device is a driver IC for laser diodes in

continuous or pulsed operation of up to 300 kHz. The

wide power supply range of 2.7 to 6 V and the inte-

grated reverse battery protection allows for battery-

operation with two to four AA/AAA cells.

The laser diode is activated via switching input IN.

A control to the average value of the optical laser

power (APC) and integrated protective functions en-

sure nondestructive operation of the sensitive semi-

conductor laser.

The IC contains protective diodes to prevent destruc-

tion due to ESD, a protective circuit to guard against

overtemperature and undervoltage and a soft-start

circuit to protect the laser diode when switching on

the power supply. Short-term reversed battery con-

nection destroys neither the IC nor the laser diode.

An external resistor at ISET is employed to adapt the

APC to the laser diode being used. The capacitor at

CI determines the recovery time constants and the

starting time.

A watchdog circuit monitors the switching input IN.

If IN remains low longer than preset by the capaci-

tor at CWD, the capacitor of the APC is discharged

at pin CI. This ensures that the current through the

laser diode during the next high pulse at input IN is

not impermissibly high.

PACKAGES SO8, MSOP8 to JEDEC Standard

PIN CONFIGURATION SO8

1

2

3

4

8

7

6

5

GND

ISET

CI

VCC

AMD

CWD

IN

KLD

PIN CONFIGURATION MSOP8

1

GND

CWD

CI

ISET

KLD

AMD

IN

VCC

PIN FUNCTIONS

No. Name Function

1 GND

Ground

2 CWD Capacitor for Watchdog

3 CI

Capacitor for Power Control

4 ISET

Reference Current Input

5 VCC

+2.7 to +6 V Supply Voltage

6 IN

Input

7 AMD

Anode Monitor Diode

8 KLD

Cathode Laser Diode