STM’s First Reference Design for MasterGaN

STM’s First Reference Design for MasterGaN

MasterGaN Reference Design from STMicroelectronics Demonstrates Heatsink-Free 250W Resonant Converter

STMicroelectronics has released the first reference design for its MasterGaN power packages, demonstrating how the new highly integrated devices increase power density, boost energy efficiency, simplify design, and accelerate time to market.

The EVLMG1-250WLLC reference design is a 250W resonant converter with a 100mm x 60mm board outline and 35mm maximum component height. It features the MasterGaN1, which contains one half-bridge STDRIVE gate driver optimally connected to two 650V normally-off GaN transistors with matched timing parameters, 150mΩ on-resistance (Rds(on)), and 10A maximum current rating. The logic inputs are compatible with signals from 3.3V to 15V.

MasterGaN1 is suitable for high-efficiency soft-switching topologies including resonant converters, active clamp flyback or forward converters and bridgeless totem-pole PFC (power-factor correction) in AC/DC power supplies, DC/DC converters, and DC/AC inverters up to 400W.

The primary side runs heatsink-free, leveraging the high efficiency of the GaN power transistors. In addition, GaN’s superior switching performance allows a higher operating frequency than ordinary silicon MOSFETs, permitting smaller magnetic components and capacitors for greater power density and reduced bill of materials.

Designed for a nominal 400V supply, the EVLMG1-250WLLC provides a 24V/10A output and achieves maximum efficiency above 94%. Benefiting from MasterGaN’s integrated safety features, the converter output is protected against short circuit and overcurrent. There is also brown-out protection and an input-voltage monitor that permits sequencing within an array of DC/DC converters and prevents a motor from starting under low-voltage conditions.

ST’s MasterGaN family comprises pin-compatible integrated half-bridge products including symmetrical and asymmetrical configurations, housed in a 9mm x 9mm low-profile GQFN package.  Containing circuitry rated up to 650V, the packages have over 2mm creepage distance between high-voltage and low-voltage pads. MasterGaN modules are available in various power ratings, allowing engineers to scale their designs with minimal hardware changes.

Key Features

  • High efficiency and compact solution for DC/DC conversion using MasterGaN1
  • Output voltage: 24 V
  • Output power up to 250 W
  • Nominal Input voltage: 400 V +/- 10%
  • Efficiency: >92%
  • Outputs protected against short-circuit and overcurrent
  • Input voltage monitor for correct sequencing as D2D converter, and brownout protection
  • Board size: 100 x 60 (W x H) mm. Maximum components height: 35 mm
  • WEEE and RoHS compliant
  • Applications: industrial DC-DC applications, adapters, consumer SMPS


GaN technology enables these devices to handle more power even as they become smaller, more lightweight, and more energy-efficient. These improvements will make a difference for smartphone ultra-fast chargers and wireless chargers, USB-PD compact adapters for PCs and gaming, as well as in industrial applications like solar-energy storage systems, uninterruptible power supplies, or high-end OLED TVs and server cloud.

The EVLMG1-250WLLC is available now from and distributors, for $230.00.

About the Demonstration Board

This demonstration board is a resonant LLC converter dedicated to any kind of industrial application where minimum size and high efficiency is required, based on MasterGaN1. This device, embedding a couple of GaN power transistors and a driver in the same package, allows to interface directly any kind of SMPS controller. Thanks to the GaN technology and to the embedded driver, the converter can be designed with an operating frequency higher than using conventional MOSFETs. Actually, the board has no heatsinks on the primary side and has very reduced dimensions; the power density is 20 W/inch^3. The high efficiency and small size make the board suitable also when available space is limited.

Output power can be up to 250 W at 24 Vdc. Converters come with overcurrent, short-circuit and overvoltage protection. The input voltage monitoring allows the startup with correct sequencing of cascade converters, preventing operation with too low input voltage.

The board is composed of a motherboard with the transformer and the primary controller, and two small daughterboards: one on the primary side embeds the MasterGaN1, another on the secondary side has the SR controller SRK2001 and the MOSFETs.


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