GaN versus Silicon Which, where, why, how

GaN transistors: are they ready to replace silicon FETs?

I would like to start a discussion regarding GaN transistors for power conversion applications. I picked three pairs of transistors based on the first set of parameters a designer will use to filter possible parts for a specific application: breakdown voltage and Rdson. I would like to see comments, particularly from real power supply designers regarding:

 - Which part would you choose and why?

 - How important is a lower Ciss in a real application from efficiency perspective.

 - Is it 125ºC maximum junction temperature OK or not?

 - Do you see gate driving requirements important in selecting silicon versus GaN parts?

 - Do you have a real-life, apples-to-apples comparison, GaN versus Silicon solution for the same final application?

 - Should we pick a different set of parts for GaN/Silicon comparison?

The comments should help both power supply designers and manufacturers of silicon and GaN transistors. Here are the contenders:

Post your comments on www.GoToPower.net or SMPS Power Supplies group on LinkedIn.