A 16 bit Incremental ADC with Swapping DAC for Low Power Sensor Applications

Abstract

This paper describes a 16-bit incremental analog-to-digital converter (ADC) for sensor applications. To implement a wide applicable ADC, which can be used in the commercial case, a full-on-chip voltage reference for the delta-sigma (Delta Sigma) ADC is incorporated. The swapping digital-to-analog converter (DAC) is proposed in the loop-filter to minimize the noise effect of the voltage reference, which can directly deteriorate the effective resolution (ER) of the read-out system. Furthermore, gain programmable characteristic is embedded in the ADC for various applications. Measurements show that the ADC achieves 16.07-bit ER and 10 LSB integral nonlinearity (INL), while dissipating only 18 mu A current from a 3.3 V supply. The ADC was fabricated in a 0.18-mu m standard CMOS process with a 0.182 mm(2) active area.