A 350-nW Low-Noise Amplifier With Reduced Flicker-Noise for Bio-Signal Acquisition
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Proceedings 2020 Austrochip Workshop on Microelectronics
For the acquisition of bio-signals, like EEG or ECG, there is a need for low-noise amplifiers that are capable of amplifying input-signals with high source-impedance at very low frequencies <1 Hz, while rejecting DC-offsets > 100 mV at the electrode-tissue interface, ideally without using external components. This fully differential amplifier achieves a gain of 38.7 dB with a CMRR of 74 dB and an input-referred noise of 0.97 ?Vrms while consuming 350 nW of power at 1 V supply voltage. This renders the amplifier well suited for RF-powered wireless bio-sensing applications. The amplifier uses a flickernoise reducing switched capacitor feedback and a special method of metal-metal capacitor design to maximize the area-density. This fully-integrated design is implemented in a 1P6M 180 nm CMOS technology using 0.42 mm².