New Industry Products

UnitedSiC Introduces Four 750V SiC FETS as Part of its Gen 4 SiC FET Platform

December 01, 2020 by Gary Elinoff

UnitedSiC’s gen 4 technology enables enhanced figures of merit.

The new UJ4CO75018K3S/K4S can handle 81 amps of continuous drain current with an RDS(on) of 18 mΩ, while the UJ4CO75018K3S/K4S features a 60 mΩ RDS(on) and can control 28 amps.


UnitedSiC’s Introduces Four 750V SiC FETS as Part of its Gen 4 SiC FET Platform Figure
Image courtesy of UnitedSiC


In many ways, designers of SiC FETs are playing a game of whack a mole, in that improvements in one parameter come at the expense of another. UnitedSic’s Gen 4 technology enables improvements both in individual specifications, and in what are often antagonistically related pairings. 

Specifically, the new units deliver what the company describes as best-in-class RDS(ON) times area. For specific RDS(ON) values, the units feature improved reverse recovery charge (Qrr) and 

turn on (Eon) - turn off (Eoff) losses. Additionally, the Eoss (stored energy) is reduced. 

Additionally, the four devices in this group all sport a gate charge (Qg) of 37.8nC

Nonetheless, specifications will vary with temperature as well as with other factors, and the astute designer will study the ramifications carefully before making a design decision.


Key parameters of the new UJ4CO750 group of SiC MOSFETs
Key parameters of the new UJ4CO750 group of SiC MOSFETs. Modified image courtesy of UnitedSiC Marketing Update


Kelvin Connections and Cascodes

In a previous article detailing United SiC’s earlier SiC FETS, we discussed the purpose of Cascodes,  and the utility of a fourth “Kelvin” lead.

Cascodes consist of a high voltage SiC JFET controlled by a low voltage Si MOSFET. The latter’s standard gate-drive characteristics allows the new device to be a “drop-in replacement” for last-generation devices such as silicon IGBTs. All four of the new devices employ cascode circuit configurations and feature typical gate threshold voltages of 4.8 volts.  

Kelvin Leads overcome the issue of the high input inductances that are characteristic of T0-247 packages, which will limit switching speeds. Two of the four new devices employ a fourth “Kelvin” lead.


3-lead package without a Kelvin lead.
3-lead package without a Kelvin lead. Image courtesy of UJ4CO75018K3S Data Sheet
4-lead package with a Kelvin lead.
4-lead package with a Kelvin lead. Image courtesy of UJ4CO75018K4S Data Sheet


The UJ4CO75060K3S and the UJ4CO75060K4S are similar.


The UJ4CO75018K3S and the UJ4CO75018K4S 

Shared features include:

  • On-resistance RDS(on): 18mW (typ)
  • Reverse recovery: Qrr = 102nC
  • Body diode VFSD: 1.14V

However, because of the Kelvin leaded TO-247-4L package, the UJ4CO75018K4S offers cleaner gate waveforms and faster switching.


The UJ4CO75060K3S and the UJ4CO75060K4S

Both of these SiC FETS feature:

  • On-resistance RDS(on): 58mW (typ)
  • Reverse recovery: Qrr = 52nC
  • Body diode VFSD: 1.31V

As in the case of the previous pair, the Kelvin lead serves to enable cleaner gate waveforms and faster switching.


New Gen 4 Devices on the Horizon

As Anup Bhalla, VP Engineering at UnitedSiC, explains: “These devices help address the challenges facing engineers working across sectors with the highest voltage and power demands - from DC-DC conversion and on-board charging to power factor correction and solar inverters.”

He goes on to state that “We will be announcing many new Gen 4 devices over the next 9 months which will further improve on cost-effectiveness, heat efficiency and design headroom. This will support all sectors in overcoming the challenges of mass adoption and to accelerate innovation.”



  • PV inverters
  • EV Charging
  • Switching power supplies (SMPS)
  • Power factor correction (PFC) modules
  • Induction heating
  • Motor drives


Physical and Environmental Considerations

  • ESD protected to HBM class 2
  • AEC-Q101 qualified
  • Lead free
  • Halogen free
  • Maximum operating temperature is 175℃
  • Available in TO247-3L and TO247-4L packages