New low-power 1.5-bit time-interleaved MDAC based on MOS capacitor amplification

Abstract

In this paper a new time-interleaved 1.5-bit MDAC circuit is proposed. This circuit is well suited to be used in ultra low-power high-speed 4-to-8 bits pipeline ADCs. The required gain of two is implemented by switching a MOS capacitor from inversion into depletion within a clock-cycle. Low-power is achieved since no operational amplifiers are required but, instead, simple source-followers are used. Simulation results of a complete front-end stage of a 6-bit 2-channel pipeline ADC demonstrate the efficiency of the proposed technique.