Analog Devices’ new LT8418 GaN driver

ADI now offers a 100V half-bridge GaN driver that simplifies the implementation of GaN FETs, proving 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 provides strong current sourcing/sinking capability with 0.6Ω pull-up and 0.2Ω pull-down resistance for driving a variety of GaN FETs. It also integrates a smart integrated bootstrap switch to generate a balanced bootstrap voltage from VCC with a minimum dropout voltage.

The LT8418 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 pulsed width modulation inputs of the LT8418, INT and INB, are independent and TTL logic compatible for precise control. The LT8418 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, the LT8418 employs the WLCSP package to minimise parasitic inductance, enabling its wide use in high-performance and high-power density applications.

Product specifications

• Split 0.6Ω pull-up and 0.2Ω pull-down gate drivers for adjustable turn on/off behaviour
• 4A peak source, 8A peak sink current capability
• Lower propagation delay: 10ns typical
• Propagation delay matching: 1.5ns typical
• High dv/dt immune up to 50V/ns
• Under-Voltage (VCC & BST) and Over-Voltage (VCC) lockout protections
• Smart integrated bootstrap switch will regulate the HS gate drive voltage to operate within the SOA of the GaN FETs