GaN driver enables robust and reliable control of GaN FETs

Analog Devices, Inc. now supplies a 100V half-bridge GaN driver that simplifies the implementation of GaN FETs, providing robust gate control, high-frequency switching, and increased system efficiency. Integrating top and bottom driver stages, driver logic control, and protections, the new LT8418 can be configured into synchronous half-bridge, full-bridge topologies or buck, boost, and buck-boost topologies. The device supplies strong current sourcing/sinking capability with 0.6-Ohm pull-up and 0.2-Ohm pull-down resistance for driving various GaN FETs. It also incorporates a smart integrated bootstrap switch to generate a balanced bootstrap voltage from VCC with a minimum dropout voltage.

The device delivers split gate drivers to adjust the turn-on and turn-off slew rates of GaN FETs to suppress ringing and optimise EMI performance. All driver inputs and outputs have default low-state to prevent GaN FETs from false turn-on. The PWM inputs of the driver, INT, and INB are independent, and TTL logic is compatible for precise control. The device performs with a fast propagation delay of 10ns and maintains a delay matching of 1.5ns between the top and bottom channels, making it suitable for high-frequency DC-DC converters, motor drivers, and class-D audio amplifiers. In addition, it employs the WLCSP package to minimise parasitic inductance, allowing its wide use in high-performance and high-power density applications.