1-GHz GaAs ADC building blocks

GaAs ICs for high-speed, 6-b, 1G-sample/s (Gs/s) data acquisition are under development, using a low-cost conventional D-MESFET technology. First-generation sample-and-holds (S/Hs) and comparators are currently being sampled to customers. Diode-bridge and FET-switch S/Hs have been compared. Best performances have been achieved with diode-bridge switches: 1 ns and 6 bits. Comparators provide 6-b sensitivity at 1 GHz, but require offset adjustments. Second-generation analog-to-digital converter (ADC) building blocks have been made. Performances and applications of resulting circuits as well as advanced ADC design criteria are discussed, with special attention to yield. First results on a 4-b ADC are presented.<
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