A GIGASAMPLE 2ND 5-B ADC WITH ON-CHIP TRACK AND HOLD BASED ON AN INDUSTRIAL 1-MU-M GAAS-MESFET E/D PROCESS

To enhance the dynamic accuracy of high-speed A/D conversion, a 5-b flash converter with on-chip track-and-hold circuitry (T&H) has been developed. The design is based on TriQuint's commercial 1-mum GaAs E/D MESFET process. Dynamic characterization has been performed up to 1 gigasample/second (GS/s). An accuracy of 4.4 effective bits even at 1 GS/s with full Nyquist input was achieved. A comparison showing the accuracy with T&H in operation and in tracking only mode is given. The outstanding performance is due to a carefully designed T&H and the use of differential source-coupled FET logic (SCFL) in the converter.