T0806 Datasheet, PDF (1/7 Pages) ATMEL Corporation – 3 CHANNEL LASER DRIVER WITH RF OSCILLATOR AND 2 OUTPUTS

Features
• Current-controlled Output Current Source, 3 Input Channels
• Two Selectable Outputs for Grounded Laser Diodes
• Output Current per Channel up to 250 mA
• Total Output Current to 300 mA (Minimum)
• Rise Time 1.0 ns, Fall Time 1.1 ns
• On-chip RF Oscillator
• Control of 2 Different Swings by Use of 2 external Resistors
• Oscillator Frequency Range from 200 MHz to 600 MHz
• Oscillator Swing to 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 (Combo Drives)
• Combo Drives with CD and DVD Writing Capability
3-Channel Laser
Driver with
RF Oscillator
and 2 Outputs
Description
The T0806 is a laser diode driver for the operation of two different grounded laser
diodes for DVD-RAM (650 nm) and CD-RW (780 nm) drives. 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 channels 2 and 3 are pro-
vided 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 outputs IOUTA or IOUTB by the select input
SELA. Each channel can contribute up to 250 mA to the total output current of up to
300 mA. A total gain of 100 is provided between each reference 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.
Figure 1. Block Diagram
I3
NE3
Channel 3
IOUTA
I2
NE2
Channel 2
IOUTB
T0806
Summary
IR
ENABLE
Read channel
ENOSC
RF oscillator
RF RSA RSB
SELA
Rev. 4522ES–DVD–01/04