An Ultra-Low-Voltage 160 MS/s 7 Bit Interpolated Pipeline ADC Using Dynamic Amplifiers

This paper presents a 0.55 V, 7 bit, 160 MS/s pipeline ADC using dynamic amplifiers. In this ADC, high-speed open-loop dynamic amplifiers with a common-mode detection technique are used as residue amplifiers to increase the ADC's speed, to enhance the robustness against supply voltage scaling, and to realize clock-scalable power consumption. To mitigate the absolute gain constraint of the residue amplifiers in a pipeline ADC, the interpolated pipeline architecture is employed to shift the gain requirement from absolute to relative accuracy. To show the new requirements of the residue amplifiers, the effects of gain mismatch and nonlinearity of the dynamic amplifiers are analyzed. The 7 bit prototype ADC fabricated in 90 nm CMOS demonstrates an ENOB of 6.0 bits at a conversion rate of 160 MS/s with an input close to the Nyquist frequency. At this conversion rate, it consumes 2.43 mW from a 0.55 V supply. The resulting FoM of the ADC is 240 fJ/conversion-step.