ATR0808 Datasheet, PDF (1/8 Pages) ATMEL Corporation – Three Channel Laser Driver with RF Oscillator and Two Outputs

Features
• Current-controlled Output Current Source with 3 Input Channels
• Two Selectable Outputs for Grounded Laser Diodes
• Output Current per Write Channel: 350 mA
• Total Output Current: 500 mA
• 200 Ω Channel Input Resistance
• On-chip RF Oscillator
• Control of Two Different Swings by Use of Two External Resistors
• Oscillator Frequency Range from 200 MHz to 500 MHz
• Oscillator Swing: 100 mA
• Single 5 V Power Supply
• Common Enable/Disable Input
• TTL/CMOS Control Signals
• Small Pb-free QFN16 (4 mm × 4 mm) or SSO16 Package
Applications
• DVD-ROM with CD-RW Capability
• DVD+RW with CD-RW Capability
• DVD-RW with CD-RW Capability
• Writable Optical Drives
Three Channel
Laser Driver
with RF
Oscillator and
Two Outputs
ATR0808
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.
Summary
Rev. 4724ES–DVD–01/04