The M66512 is a semiconductor laser-diode driver for driving a specific type* of semiconductor laser, in which the anode of a semiconductor laser diode is connected in stem structure to the cathode of a monitoring photodiode. The amplitude of laser drive current is set by applying a voltage from an external source. the M66512 is capable of driving laser diodes on a maximum current of 120 mA. It operates on a 5-V single power supply and switches laser drive current at a rate of 40 Mbit/s. *: The N type of Mitsubishi's semiconductor lasers.