A Single-Temperature-Calibration 0.18-µm CMOS Time-Based Resistive Sensor Interface with Low Drift over a −40°C to 175°C Temperature Range

Abstract

This paper presents a very-low-drift 0.181µ m CMOS time-based resistive-bridge sensor interface. It exhibits only 3.8 ppm/° C gain drift and 0.3 ppm/°C offset drift for the entire −40°C to 175°C temperature range using a single-temperature calibration scheme and no external accurate references nor components. The interface provides a 15 ENOB for a 100ms conversion time, consuming 3.41mW of power and 0.26mm2 of active area. The holistic drift-resilience strategy combines time-based chopping and VCO tuning to remove the DC and low-frequency errors introduced by VCO nonidealities and drift.