This paper analyses the effect of decreasing the operating temperature on the electrical characteristics of 1100 V epitaxial EST structures. Detailed performed static and transient measurements on ceramic packaged devices at 77 K have shown a significant increase of the maximum controllable current density and a notable reduction of the transient losses and the turn-off time. A reduction of the on-state voltage drop with temperature is observed at current density values higher than 80 A/cm2 (positive coefficient), leading to a more uniform turn-off process. Furthermore, a model is provided to include the temperature effect on the latching current of the main and parasitic thyristor, transconductance and dynamic parameters. © 1999 Elsevier Science Ltd. All rights reserved.