A 10-b 320-MS/s Stage-Gain-Error Self-Calibration Pipeline ADC

A 10-b 320-MS/s pipeline analog-to-digital converter (ADC) with low dc gain opamps, as low as 30.6 dB based on simulations, in its multiplying digital-to-analog converters (MDACs) is presented. A foreground self-calibration technique is proposed to reduce stage gain error by adjusting feedback factor with a calibration capacitor array. The prototype in 90-nm low-power CMOS technology achieves conversion rate of 320 MS/s with peak SFDR and SNDR of 66.7 and 54.2 dB, respectively. The total power dissipation is 42 mW, and it occupies an active chip area of 0.21 mm² including the calibration circuit. It results in a figure-of-merit (FOM) of 442 fJ/conversion-step. Only 168 clock cycles are used, and no external precise reference sources are needed for the calibration.