A 12b 200MS/s frequency scalable zero-crossing based pipelined ADC in 55nm CMOS

Abstract

A 12-bit 200MS/s zero-crossing based pipeline ADC is presented. A coarse phase followed by a level-shifted fine phase is employed for higher accuracy. To enable high frequency operation, sub-ADC flash comparators are strobed immediately after the coarse phase. The ADC occupies 0.276mm2 in 55nm CMOS and dissipates 28.5mW. 62.5dB SNDR and 78.6dBc SFDR with a 99.6MHz input signal at 200MS/s are achieved for a FOM of 131fJ/step. The reference buffer, bias circuitry, and digital error correction circuits are all implemented on chip.