9.8 An energy-efficient 3.7nV/√Hz bridge-readout IC with a stable bridge offset compensation scheme

Abstract

Wheatstone bridge sensors are often used in precision instrumentation and measurement systems, e.g., for μK-resolution temperature sensing in wafer steppers [1] and mPa-resolution differential pressure sensing in precision air gauges [2]. Since they output small differential signals superimposed on a large common-mode (CM) voltage, typical bridge readout ICs (ROICs) consist of an instrumentation amplifier (IA) followed by an ADC [1]. This paper describes a low-noise energy-efficient ROIC, which achieves a 3.7nV/√Hz input-referred noise PSD and a power efficiency factor (PEF) of 44.1. The latter represents a 5× improvement on the state of the art [3].