A low-noise self-calibrating dynamic comparator for high-speed ADCs

Abstract

This paper presents a low offset voltage, low noise dynamic latched comparator using a self-calibrating technique. The new calibration technique does not require any amplifiers for the offset voltage cancellation and quiescent current. It achieves low offset voltage of 1.69 mV at 1 sigma in low power consumption, while 13.7 mV is measured without calibration. Furthermore the proposed comparator requires only one phase clock while conventionally two phase clocks were required leading to relaxed clock. Moreover, a low input noise of 0.6 mV at 1 sigma, three times lower than the conventional one, is obtained. Prototype comparators are realized in 90 nm 10M1P CMOS technology. Experimental and simulated results show that the comparator achieves 1.69 mV offset at 250 MHz operating, while dissipating 40 muW/GHz ( 20 fJ/conv. ) from a 1.0 V supply.