A 6-to-10-Bit 0.5 V-to-0.9 V Reconfigurable 2 MS/s Power Scalable SAR ADC in 0.18 $\mu{\rm m}$ CMOS

An asynchronous successive approximation register (SAR) analog-to-digital converter (ADC) for sensor applications is presented. High linear and power efficient switching scheme is proposed. The proposed low leakage latched dynamic cell in SAR logic and wide range configurable delay element extend the flexibility of speed and resolution tradeoff. The ADC fabricated in 0.18 μm CMOS process covers 6-10 bit resolution and 0.5 V-0.9 V power supply range. At 10 bit mode and 0.5 V operation, the proposed SAR ADC achieves 56.36 dB SNDR and 67.96 dB SFDR with sampling rate up to 2 MS/s, corresponding to a figure-of-merit of 20.6 fJ/conversion-step. The proposed ADC core occupies an active area of about 300×700 μm².