A 200-MS/s 98-dB SNR track-and-hold in 0.25-um GaN HEMT

In order to overcome the design challenges of GaN HEMT leakage and Schottky diode turn-on, a GaN track-and-hold (T/H) circuit with 20-V pseudo-differential input swing consists of an asymmetric gate device followed by a symmetric gate device. The GaN T/H provides 98-dB SNR at 200 MS/s while drawing 195 mA.