Low-power 4-bit flash analogue to digital converter for ranging applications

A 4-bit 700 MS/s flash ADC is presented in 0.18 m CMOS. By lowering the kickback noise of the individual comparators it was possible to reduce the power consumption to 4.43 mW. Improved calibration capabilities resulted in an INL and DNL smaller than 0.25 LSB. These low nonlinearities give rise to 3.77 effective number of bits at the Nyquist input frequency and this in turn yields an overall figure of merit of 0.46 pJ per conversion step, the lowest figure of merit reported for ADCs with sampling rate above 500 MHz in 0.18 m CMOS.