Design and Implementation of A High-Precision Low-Power Instrumentation Amplifier

Abstract

This paper presents a high-precision and low-power two-stage miller-compensated instrumentation amplifier for sensor readout circuits. Folded-cascode structure with complementary input differential pairs and translinear-loop-based class AB circuit are adopted as the amplifier first and second stages respectively, to achieve rail-to-rail input and output ranges. The presented instrumentation amplifier is implemented in a 0.18μm BCD technology. Measurement results show that with a load of 100pF and 100kΩ, the presented amplifier achieves 79. 79dB gain, 1. 35MHz gain-bandwidth product (GBW) and 92. 3dB power supply rejection ratio (PSRR). The measured amplifier gain error is 0.11%; and its input offset voltage is 0. 3mV. This amplifier totally consumes 0. 19mW power from a 3V supply voltage.