A 1000 Mhz low power and high speed 8-bit flash ADC architecture using 90nm cmos technology

Abstract

The design objective is to implement a Low power, High speed and High resolution Flash ADC with increased sampling rate. To make this possible the blocks of ADC are analyzed. The resistive ladder, comparator block, encoder block are the major modules of flash ADC. Firstly, the comparator block is designed so that it consumes low power. A NMOS latch based, PMOS LATCH based and a Strong ARM Latch based comparators were designed separately. A comparative analysis is made with the comparator designs. Comparators in the design is reduced to half by using time domain interpolation. Then a reference subtraction block is designed to generate the subtraction value of voltages easily and its given as input to comparator. Then a more efficient and low power consuming fat tree encoder is designed. Once all the blocks were ready, a 8 bit Flash Analog to Digital Converter was designed using 90nm CMOS technology and all the parameters such as sampling rate, power consumption, resolution were obtained and compared with other works.