A Low Noise Low Power DC Coupled Sensor Amplifier with Offset Cancellation

A 16-channel sensor amplifier was designed in the Jazz 0.18μm CMOS process. The sensor amplifier has programmable gain from 20 to 2000 and a DC offset cancellation of ±0.3V using bulk voltage control. A charge pump, band gap reference and a resistor string DAC were designed for bulk voltage control. Input referred noise of 0.465μV was achieved at a gain of 2000. The power required per channel was 900μW and the supply voltages were ±V. Simulation results show the total harmonic distortion to be 0.017% and signal-to-noise-and-distortion (SINAD) ratio is 78 dB.