T0820_05 Datasheet, PDF (1/12 Pages) ATMEL Corporation – 4-channel Laser Driver with RF Oscillator

Features
• Current-controlled Output Current Source with 4 Input Channels
• Low-power Consumption
• Output Current up to 150 mA, Read Channel and Channel 2
• Output Current up to 200 mA, Channel 3 and Channel 4
• Total Output Current to 300 mA
• Rise Time 1.0 ns, Fall Time 1.1 ns
• On-chip RF Oscillator
• Control Frequency and Swings by Use of 2 External Resistors
• Oscillator Frequency Range from 200 MHz to 600 MHz
• Oscillator Swing to 100 mA
• Single 5V Power Supply
• Common Enable/Disable Input
• TTL/CMOS Control Signals
• Small SSO16 Package
4-channel Laser
Driver with RF
Oscillator
T0820
Application
• DVD-RAM
• DVD-RW
• DVD+RW
• CD-RW
• Writable Optical Drives
1. Description
The T0820 is a laser diode driver for the operation of a grounded laser diode for
writable optical drives. It includes four channels for four different optical power levels
which are controlled by a separate IC. The read channel generates a continuous
output level whereas channels 2 to 4 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 at the IOUT pin. Read channel and
channel 2 can contribute up to 150 mA and channels 3 and 4 up to 200 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. Frequency and swing can be
set by two external resistors. Oscillation is enabled by a "high" at the ENOSC pin.
Complete output current and oscillator switch-off is achieved by a `low' at the ENABLE
input.
Rev. 4506G–DVD–11/05