A 1 GS/s 6 Bit 6.7 mW Successive Approximation ADC Using Asynchronous Processing

An asynchronous 6 bit 1 GS/s ADC is achieved by time interleaving two ADCs based on the binary successive approximation (SA) algorithm using a series capacitive ladder. The semi-closed loop asynchronous technique eliminates the high internal clocks and significantly speeds up the SA algorithm. A key feature to reduce the power in this design involves relaxing the comparator requirements using an error correction technique, which can be viewed as an extension of the SA algorithm to remove degradation due to metastability. Fabricated in 65 nm CMOS with an active area of 0.11 mm², it achieves a peak SNDR of 31.5 dB at 1GS/s sampling rate and has a total power consumption of 6.7 mW.