The GS66504B is an enhancement mode GaN-on-silicon power transistor. The properties of GaN allow for high current, high voltage breakdown and high switching frequency. GaN Systems implements patented Island Technology® cell layout for high-current die performance & yield. GaNPX™ packaging enables low inductance & low thermal resistance in a small package. The GS66504B is a bottom-side cooled transistor that offers very low junction-to-case thermal resistance for demanding high power applications. These features combine to provide very high efficiency power switching.GaN Systems has introduced the GS66504B-MR part number. This reflects a move to high volume production, with associated finalized production test limits and production test flow. This New Part Number will replace the GS66504B-E01-MR. The E0x and non-E0x are equivalent devices. They are tested to the same production test limits and have the same datasheet specifications.