MasterGaN6 Power IC Integrates 650 V GaN Half-Bridge With High-Voltage Driver

STMicroelectronics has released the MasterGaN6, the opening entry in the second generation of the company’s MasterGaN half-bridge family. Like its predecessors, the device is a power system-in-package that combines a gate driver and GaN power transistors in a single 9 mm × 9 mm QFN — but the MasterGaN6 expands the feature set meaningfully, particularly around system management and protection.

STMicroelectronics kicks off the second generation of its MasterGaN power ICs family with the MasterGaN6. Image used courtesy of STMicroelectronics

MasterGaN6 650 V GaN Half-Bridge

At the heart of the MasterGaN6 power IC is a pairing of an updated BCD gate driver with a 650 V enhancement-mode GaN HEMT rated at 140 mΩ R_DS(on). The previous first-generation devices, such as the MasterGaN1, had a resistance of 150 mΩ, so the new device improves on conduction losses while maintaining the same voltage class.

The MasterGaN6 handles up to 10 A of current and integrates LDOs and a bootstrap diode to ensure optimal driving while reducing the external component count. The bootstrap diode is particularly useful for supplying the high-side driver during start-up, a detail that would otherwise require external circuitry.

GaN transistors in a half-bridge configuration have no intrinsic body diode, eliminating reverse recovery losses, which is a meaningful advantage over silicon MOSFETs in hard and resonant switching topologies alike. The MasterGaN6 permits reverse conduction in both the on-state and off-state, and anti-parallel diodes are not required for operation in either resonant or hard-switching modes. However, they can be added to improve efficiency when reverse conduction losses are significant.

Functional block diagram of the MasterGaN6. Image used courtesy of STMicroelectronics

New Features and System Integration

The most notable additions in the second-generation MasterGaN half-bridge family are the dedicated pins for fault indication and standby control. The FLT pin is an open-drain output that signals the operating status externally, including UVLO, overtemperature, and shutdown states. The shutdown pin is active-low, giving designers a straightforward way to put the device into low-power standby without removing the supply rail. These additions enable tighter integration with system microcontrollers and power management firmware, particularly in designs where real-time fault monitoring matters.

The advanced driver allows high-frequency operation thanks to its low minimum on-time and propagation delays, helping designers minimize circuit footprint. The turn-on gate resistance is also externally adjustable via RON pins, allowing designers to tune the turn-on slew rate to suit their specific converter topology and EMC requirements.

Designers can begin their development with the EVLMG6 evaluation board. Image used courtesy of STMicroelectronics

Applications and Supported Topologies

MasterGaN6 is designed for consumer and industrial applications, including chargers, adapters, lighting power supplies, and DC-to-AC solar micro-inverters. Its half-bridge configuration suits diverse topologies, including active-clamp flyback, resonant LLC, inverse buck converters, and PFC circuits. The 650 V breakdown voltage keeps the part comfortably within reach of universal AC-offline designs, which typically need to handle peak rectified mains voltages of around 400 V.

To help designers get up and running, STMicroelectronics has released the EVLMG6 evaluation board alongside the product launch. The MasterGaN6 model has also been added to STMicroelectronics’ eDesignSuite PCB Thermal Simulator, enabling engineers to estimate thermal behavior before committing to a layout.

MasterGaN6 is in production now, priced at $4.14 per 1,000 pieces.