TIQ flash ADC with threshold compensation

Threshold Inverter Quantizer (TIQ) is a novel idea which can effectively replace the reference voltage generator, resistive/capacitive voltage divider network and array of differential comparators in a conventional flash Analog to Digital Converter (ADC) by an internal reference comparator array constructed of Complementary Metal Oxide Semiconductor (CMOS) inverters. The inverter threshold voltage serving as the reference voltage, this architecture claims large improvements in terms of silicon area, power consumption and operating speed. Perturbations due to sensitivity of the inverter threshold voltage to operating temperature/process variations pose impediments in such ADC designs and strongly demand a compensation scheme to such variations. This paper presents a TIQ based flash ADC, with inverter threshold voltage compensation for a flash ADC architecture which is thermally reliable up to 120 °C. The complete circuit is modeled in cadence virtuoso simulation suite with gpdk 180 nm design library.