Rev. 4724ES–DVD–01/04

Features

Ω Channel Input Resistance

× 4 mm) or SSO16 Package

Applications

Description

The ATR0808 is a laser diode driver for the operation of two different grounded laser

diodes for DVD-RW/DVD+RW (650 nm) and CD-RW (780 nm). It includes three chan-

nels for three different optical power levels which are controlled by a separate IC. The

read channel generates a continuous output level, whereas the channels 2 and 3 are

provided as write channels with very fast switching speeds. Write current pulses are

enabled when a low signal is applied to the NE pins. All channels are summed

together and switched to one of the two IOUTA or IOUTB outputs by the select input

SELA. Each write channel (channel 2 and 3) can contribute up to 350 mA to the total

output current, up to 500 mA. The read channel can contribute up to 150 mA. Total

gains of 100 (read channel), 250 (channel 2 and 3) are provided between each refer-

ence current input and the selected output. Although, the reference inputs are current

inputs, voltage control is possible by using external resistors. An on-chip RF oscillator

is provided to reduce laser mode hopping noise during read mode. Swing can be set

independently for the two selectable outputs with two different resistors. Oscillation is

enabled by a high signal at the ENOSC pin. Complete output current and oscillator

switch-off is achieved by a low signal at the ENABLE input.

Three Channel

Laser Driver

with RF

Oscillator and

Two Outputs

ATR0808

Summary