A single die 1.2 V 55 to 95 dB DR delta sigma ADC with configurable modulator and OSR

Abstract

A single die 1.2 V multi-stage noise shaping (Mash) 2-2 delta sigma analog to digital converter (ADC) for wide applications is implemented. The configurable Mash 2-2 modulator with a new decimation filter design is presented to achieve wide and high dynamic range (DR) for multiple practical applications. The novel modulator can be configured as a Mash 2-2 modulator for high precision or a 2-order modulator for low DR. The decimation filter is designed to select the OSR flexibly among cascaded integrator comb (CIC) filter and two half-band filters (HBF). The serial peripheral interface (SPI) can be used to adjust the sampling frequency and the oversampling ratio (OSR). The design was fabricated in a 0.13 μm CMOS process with an area of 0.91 mm2 and a total power of 5.2 mW. The measurement results show that the dynamic range (DR) of the proposed ADC can change from 55 to 95 dB with the configurable OSR from 16 to 256. The spurious free dynamic range (SFDR) and signal-to-noise distortion ratio (SNDR) can get 99 dB and 86.5 dB, respectively.