An ultra low-power CMOS instrumentation amplifier for biomedical applications

Abstract

An ultra low-power biopotential instrumentation amplifier, based on the current balancing technique is presented. An internal programmable high-pass filter has been included in the instrumentation amplifier to filter out low-frequency artifacts if necessary. The instrumentation amplifier was fabricated in a multi-project test chip in 035μ mixed mode CMOS process through MOSIS. Measurement results show that the instrumentation amplifier draws a current of 9μA from a 3.3 V lithium-ion battery and it has CMRR of 100 dB and input voltage dynamic range of ±6 mV. The input referred noise voltage is 0.3μV/√Hz with a flicker noise corner frequency of 15 Hz. Design methodology and experimental results along with measurement issues are given in this paper.