The GS66506T from GaN Systems is a GaN Power Transistor with Gate Threshold Voltage 1.1 to 2.6 V, Drain Source Voltage 650 V, Drain Source Resistance 67 to 175 milli-ohm, Continous Drain Current 18 to 22.5 A, Pulsed Drain Current 48 A. Tags: Die. More details for GS66506T can be seen below.