A 6-bit 3.5-GS/s 0.9-V 98-mW Flash ADC in 90nm CMOS

Abstract

A 6-bit 3.5-GS/s flash ADC is fabricated in a 90nm CMOS process. A clamp diode with a replica biasing and an acceleration capacitor are introduced for high-speed overdrive recovery. Averaging network is analyzed to explore the effect of tail current mismatch. The 3.5-GS/s ADC consumes 98mW with 0.9V power supply. Its SNDR is 31.18dB with Nyquist frequency input.