SiC JFETs – The ideal circuit protection solution

The UJN & UJ3N series are high-performance SiC normally-on JFET transistors. This series exhibits ultra-low on resistance (RDS(ON)) and gate charge (QG) allowing for low conduction and switching loss. The device normally-on characteristics with low RDS(ON) at VGS = 0 V is also ideal for current protection circuits without the need for active control.  The devices are also commonly used in series connection with a Si-MOSFET as robust ‘supercascodes’, which give all the advantages of wide band-gap technology with very high operating voltages and easy gate drive.


  • 650 V & 1200 V device options

  • Low on-resistance: RDS(on) maximum of 80mΩ

  • Current limiting: rapid current decrease due to self-heating, limiting I2t

  • Normally-on JFETs: VG(th) invariant with temperature

  • Peak TJ > 600°C

SiC JFET Selector Guide

Part Number Package V RDS(on) typ Id max
ID New Part Number Package V RDS(on) typ Id max Data Sheet SPICE Model Buy Now
1 UJN1205K¹ TO-247-3L 1200 45 38.0 Order Online
3 UJN1208K¹ TO-247-3L 1200 80 21.0 Order Online
12 UJ3N120070K3S TO-247-3L 1200 70 33.5 Order Online
13 UJ3N120035K3S TO-247-3L 1200 35 63.0 Order Online
14 UJ3N065080K3S TO-247-3L 650 80 32.0 Order Online
15 UJ3N065025K3S TO-247-3L 650 25 85.0 Order Online
  1. This product is not recommended for new designs. Instead, select the appropriate version of the UJ3N series.
  2. For all die inquiries, contact

Design Resources

Full Product Selector Guide

Reliability & Package Data

FET & JFET Datasheets / SPICE Models

Normally-On JFET limits current flow from a surge event

Ability to handle TJ > 600ºC

Back-to-back normally-on JFETs support bidirectional current limiting


Low series resistance, excellent current limiting behavior

Normally-on JFETs create self-powered two-terminal fast acting circuit breakers


High Side Switch (DC Breaker)


Reliability & Package Data


Marking and tape & reel / tube information

1200 V xJ SiC Series

Reliability Documentation

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