Right but you can make your on resistance arbitrarily small by speccing a bigger transistor. It might cost more, but there's plenty of ability to reduce the on

Right but you can make your on resistance arbitrarily small by speccing a bigger transistor. It might cost more, but there's plenty of ability to reduce the on resistance. My guess is that this is a breakthrough because it has lower resistance per unit of gate capacitance. It takes a certain amount of energy to switch the transistor on, and when you want to turn it off you generally connect it to ground so that the switch turns off very quickly. That energy is lost. I've emailed a very experienced electronics engineer friend of mine who has built more switching power supplies than anyone I know. He hasn't gotten back to me yet. It really has to be something more than the "on" resistance though. It's possible to get arbitrarily large MOSFETs and get micro-ohm resistance, where as the GaN transistor has milli-ohm resistance. http://www.digikey.com/product-detail/en/TPHR9003NL,L1Q/TPHR9003NLL1QCT-ND/4563093 http://www.digikey.com/product-detail/en/TPHR9003NL,L1Q/TPHR... http://www.gantechnology.com/products.html http://www.gantechnology.com/products.html