Gate-drive isolation for industrial power stages
The FOD8343T is a single-channel optoisolated gate driver from onsemi, built for driving IGBTs and power MOSFETs in industrial motor drives, uninterruptible power supplies, and switch-mode power converters. Its 5000 Vrms isolation rating provides the reinforced safety barrier required between the low-voltage controller side and the high-voltage power stage. With a 4 A peak output current and symmetrical 3 A source/sink capability, it can directly drive the gate of medium-power IGBTs up to the 50 A class without an external booster stage — saving board space and BOM cost. The 50 kV/µs common-mode transient immunity ensures the output stays clean when the power-stage voltage swings at hundreds of volts per microsecond — a common failure point in half-bridge and full-bridge topologies.
Switching speed and timing margin
Typical rise and fall times of 38 ns and 24 ns keep switching losses low, while a maximum propagation delay of 210 ns and pulse-width distortion of 65 ns give the control loop predictable timing — important for dead-time management in bridge circuits. The 10 V to 30 V output supply range matches the gate drive voltage of standard IGBTs and MOSFETs, and the 1.5 V typical forward voltage with 25 mA max forward current keeps the LED drive within standard microcontroller GPIO capability.
Active production — no obsolescence concern
The tube package is the standard through-hole compatible format for manual assembly or low-volume production; for reel-fed pick-and-place, the FOD8343TR2 variant is the tape-and-reel equivalent.
Package and footprint fit
Housed in a 6-SOIC (0.268", 6.80 mm width) surface-mount package with a 6-SOP supplier device package designation, the FOD8343T occupies a compact footprint on the PCB. The 6-pin SOIC layout is a common industry standard, simplifying layout reuse across multiple gate-driver designs. The -40°C to 100°C operating temperature range covers industrial environments — motor drive cabinets, solar inverters, and factory-floor power supplies — where ambient temperatures can reach 70°C with additional self-heating from adjacent power components.