ATR0809 Datasheet | Atmel

Features - - - - - - - - - - - - Current-controlled Output Current Source with 4 Input Channels Two Selectable Outputs for Grounded Laser Diodes Up to 350 m A Output Current per Channel Total Output Current up to 500 m A On-chip RF Oscillator Oscillator Frequency Range from 200 MHz to 500 MHz Individual Setting of RF Oscillator Current on Each Output by External Resistors Maximum Oscillator Current Amplitude 100 m A Single 5 V Power Supply mon Enable/Disable Input TTL/CMOS patible Control Signals Small Pb-free QFN20 or SSO20 Package Applications - - - - DVD-ROM with CD-RW Capability DVD+RW with CD-RW Capability DVD-RW with CD-RW Capability Magneto-optical Drives and Others Four Channel Laser Driver with RF Oscillator and Two Outputs ATR0809 Summary Description ATR0809 is a laser diode driver for the operation of two different grounded laser diodes for DVD-RW/+RW (650 nm) and CD-RW (780 nm). It includes four channels for four different optical power levels. All channels (channel 1 = read channel, channel 2, 3, 4 = write channels) can be controlled by fast switches. The 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 write channel (channel 2, 3 and 4) can contribute up to 350 m A to the total output current of up to 500 m A. The read channel can contribute up to 150 m A. Total gains of 100 (read channel), 250 (channel 2 and 3) and 100 (channel 4) are provided between each reference current input and the selected output. Although the reference inputs are current inputs, voltage control is also possible by using external resistors. An on-chip RF oscillator can be used to reduce laser mode hopping noise in read mode. The oscillator current amplitude and frequency can be set independently for the two selectable outputs with four different resistors. Oscillation is enabled by a high signal at the ENOSC pin. plete shutdown of the output...