New Industry Products

Transphorm’s Second 900 Volt GaN FET is Now in Production

August 24, 2020 by Gary Elinoff

This new device represents a significant improvement to the company’s first 900V device, the TP90H180PS, which sported a typical ON-resistance of 170 mΩ.

Transphorm’s TP90H050WS is a normally-OFF two-chip cascode power transistor featuring a typical ON-resistance of only 50mΩ

The JEDEC qualified device features a 1,000V spike rating and is aimed at applications in energy storage, battery charging, lighting, uninterruptible power supplies, and at photovoltaic inverters. The TP0H050WS can empower 10 kW systems to achieve better than 99% efficiency

The new device represents a significant improvement to the company’s first 900V device, the TP90H180PS, which sported a typical ON-resistance of 170 mΩ. 

The TP90H050WS. Image used courtesy of Transphorm.


“Transphorm’s work on its 900 V platform illustrates the capability of high voltage gallium nitride power transistors,” said Philip Zuk, VP of Technical Marketing and NA Sales at Transphorm. “This device gives us the ability to support applications that were not previously accessible to us. We have received strong interest when sampling these 50 milliohm FETs. We’re proud to say that their availability status has shifted now to high-volume production to meet customer demand.” 


What is a Cascode?

A cascode consists of a wide bandgap device, in this case, a GaN FET, which is co-packaged with a second semiconductor. 

Cascode Device. Image used courtesy of TP90H050WS Data Sheet.


The advantage here is that the GaN FET can be triggered by the second device, which itself is more easily triggered than the unaided GaN FET itself could be.

Key Specifications

  • Minimum drain to source voltage (VDS)  is 900 volts
  • Maximum transient drain to source voltage (V(TR)DSS) is 1000 volts
  • Maximum RDS(on)eff is 63 mΩ. This reflects both dynamic and static “on” resistance
  • Typical Reverse recovery charge (QRR) is 156 nanocoulombs
  • Typical total gate charge is (QG) is 16 nanocoulombs


The illustration below charts the efficiency of the TP90H050 vs. output power when the device is triggered at 50 kHz

Image used courtesy of Transphorm

The maximum gate voltage is ±20 volts, with a 4V threshold for increased immunity to electrical noise. This makes the unit easy to drive with readily available gate drivers

While single-phase applications can be handled by 650V devices, three-phase applications require at least 900V devices like the TP90H050WS. In a standard half-bridge configuration, the unit can deliver as much as 10 kW of power at a stated efficiency of 99%.


The TP90H050WS Forms the Basis of a Solid-State Circuit Breaker

The power converters that feed renewable power into electrical grids are somewhat delicate, and cannot handle an abnormal power surge for more than a few microseconds, and traditional mechanical circuit breakers are too slow to meet this challenge. 

To overcome this critical weakness, the Illinois Institute of Technology, through its ARPA-E CIRCUITS program, is developing solid-state circuit breakers (SSCBs) for renewable energy microgrids. The TP90H050 is at the core of this important project

“Our SSCB project required a non-traditional power conversion solution that not only outperformed mechanical circuit breakers speed-wise, but also helped us reduce power loss,” explained Dr. John Shen, IIT. “Transphorm’s GaN technology surpassed our expectations. It delivered the full package. High power density, reliable bi-directionality, and, as the only 900 V GaN device on the market, unprecedented power output in a small package.”


Physical and Environmental Specifications

The TP90H050WS is JEDEC qualified. The RoHS compliant device is available in a standard TO-247 halogen-free package. The device operates over a wide operating temperature range (case and junction) of -55 to +150°C. It’s GSD (gate source-drain) layout serves to improve high-speed design


Design Aides

The TDINV3500P100 is a 900V evaluation kit that makes it simpler to gauge the performance of GaN FETs in inverter applications including UPS and solar. 


The TDINV3500P100-KIT.  Image used courtesy of Transphorm


The unit delivers the features of a single-phase inverter operating at and above 100kHz.