ATR0841 Datasheet | Atmel

Features - - - - - - - - - - - Current-controlled Output Current Source with 4 Input Channels LVDS patible Inputs, Channel 2, 3, and 4, with On-chip 100 Ω Termination Two Selectable Outputs for Grounded Laser Diodes Output Current per Channel up to 350 m A Total Output Current up to 500 m A On-chip RF Oscillator Control of 2 Different Swings and Frequencies by Use of 4 External Resistors Oscillator Frequency Range from 200 MHz to 500 MHz Maximum Oscillator Current Amplitude 100 m App Single 5 V Power Supply Small Pb-free QFN24 4 mm × 4 mm Package Applications - DVD Blue Laser - DVD-RAM/DVD-RW/DVD+RW with CD-RW Capability - Recordable Optical Drives Description The ATR0841 is a laser diode driver designed to operate two differently grounded laser diodes for DVD-RW/+RW (650 nm) and CD-RW (780 nm). The device includes four channels for four different optical power levels. The write channels (channel 2 to 4) can be controlled by fast LVDS (Low Voltage Differential Signaling). Due to the integrated termination external resistors are not needed. The function of the read channel is to generate a continuous output current, channels 2 to 4 are designed as write channels with very fast switching speed. All channels are summed together and routed to one of the two outputs, IOUTA or IOUTB, controlled by the select input SELA. Each write channel (channels 2 to 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 gain of 100 (read channel) and 250 (channel 2, 3 and 4), respectively, are 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 available to reduce laser-mode hopping noise during read mode. The oscillator current amplitude can be set independently for the two selectable outputs with two different resistors. Oscillation is enabled by a high signal...