ATR0839 Datasheet | Atmel

.. Features - - - - - - - - - - - - Current-controlled Output Current Source with 4 Input Channels LVDS patible Inputs at Channels 2, 3 and 4 with On-chip 100Ω Termination Separate Read-channel Enable Two Selectable Outputs for Grounded Laser Diodes Output Current per Channel up to 350 m A Total Output Current up to 600 m A On-chip RF Oscillator with LVDS Enable 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 5V Power Supply Small Pb-free QFN24, 4 mm × 4 mm Package Applications - Double Layer DVD+/-RW with CD-RW Capability - Recordable Optical Drives 4-Channel LVDS Laser Driver for Dual-layer Application ATR0839 1. Description The ATR0839 is a laser diode driver designed to operate two different grounded laser diodes for DVD-RW/DVD+RW (650 nm) and CD-RW (780 nm). The device includes four channels for four different optical power levels. The write channels (channels 2 to 4) can be controlled by fast LVDS (Low Voltage Differential Signaling). The read channel generates a continuous output current, whereas 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 (channel 2 to 4) can contribute up to 350 m A to the total output current of up to 600 m A. The read channel can contribute up to 150 m A. Total gains of 100 (read channel) and 250 (channels 2, 3 and 4), 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....