This part is a kind of semiconductor called ATR0843.

Function of this product has 4-channel Laser Driver.

Manufacturers : ATMEL

Image and pinout :

Some of the text within the PDF file :

Features • • • • • • • • • • • • Current-controlled Output Current Source with 4 Input Channels LVDS/CMOS Compatible Inputs Channel 2, 3, and 4 Separate Read-channel Enable (NER) Two Selectable Outputs for Grounded Laser Diodes Output Current per Channel up to 350 mA Total Output Current up to 500 mA 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 mApp Single 5 V Power Supply Small Pb-free QFN24 Package (4 mm × 4 mm) Applications • DVD Blue Laser • DVD-RAM/DVD-RW/DVD+RW with CD-RW Capability • Recordable Optical Drives 4-channel Laser Driver with 2 Outputs and 3 LVDS Inputs, NER Enable ATR0843 Su [ ... ]

ATR0843 PDF Datasheet Download