The ISO5851 is an isolated gate driver for IGBTs and MOSFETs. Input CMOS logic and output power stage are separated by a capacitive, silicon dioxide (SiO₂), isolation barrier.

The IO circuitry on the input side interfaces with a micro controller and consists of gate drive control and RESET ( RST) inputs, READY (RDY) and FAULT ( FLT) alarm outputs. The power stage consists of power transistors to supply 2.5-A pullup and 5-A pulldown currents to drive the capacitive load of the external power transistors, as well as DESAT detection circuitry to monitor IGBT collector-emitter overvoltage under short circuit events. The capacitive isolation core consists of transmit circuitry to couple signals across the capacitive isolation barrier, and receive circuitry to convert the resulting low-swing signals into CMOS levels. The ISO5851 also contains under voltage lockout circuitry to prevent insufficient gate drive to the external IGBT, and active output pulldown feature which ensures that the gate-driver output is held low, if the output supply voltage is absent. TheISO5851 also has an active Miller clamp function which can be used to prevent parasitic turn-on of the external power transistor, due to Miller effect, for unipolar supply operation.