ATR0808-TCQ

The ATR0808-TCQ is a laser diode driver for the operation of two different grounded laser diodes for DVD-RW/DVD+RW (650 nm) and CD-RW (780 nm). It includes three channels for three different optical power levels which are controlled by a separate IC. The read channel generates a continuous output level, whereas the channels 2 and 3 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 and switched to one of the two IOUTA or IOUTB outputs by the select input SELA. Each write channel (channel 2 and 3) can contribute up to 350 mA to the total output current, up to 500 mA. The ATR0808-TCQ read channel can contribute up to 150 mA. Total gains of 100 (read channel), 250 (channel 2 and 3) 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 ATR0808-TCQ 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.