The SM9103M is a photodiode photoelectric current-to-voltage conversion head amplifier LSI for optical disk pickups in DVDRAM/DVDROM equipment. It sums the photodiode current data signals and then converts the signals to a differential signal for output. The output tracking servo and focusing servo signals are derived from built-in sum and difference circuits, and the gain for these servo signals can be adjusted using serial interface controls. Each of the signals from the photodiodes, used to generate DPD (Differential Phase Detection) tracking servo signal, is current-to-voltage converted and then also output. It operates from a single 5 V supply, and is available in 36-pin plastic SSOP packages.