A 370-nW Quad-Channel Multi-Mode Bio-Signal Acquisition AFE with 2.9-µVrms Input Noise

This paper presents a reconfigurable 4-channel electromyography, electrocardiogram, or electroencephalography bio-signal acquisition analog frontend (Bio-AFE), which is part of a chiplet further containing an ADC and an ultra-wideband transmitter for digitization and wireless data transmission, an on-chip clock-generation, and an LDO including reference. The chip occupies an area of 3.64 mm
²
in 180-nm 1P6M CMOS. A flexible recording of bio-signals is possible due to several bandwidth and gain modes (0.2 Hz to 128/512/2048 Hz, and 19.9 dB to 53.1 dB, respectively). Simultaneously, a high common-mode rejection ratio of 81.6 dB, a differential input impedance of 216 MΩ, and a low input-referred noise ranging from 2.9 µV
rms
to 7.1 µV
rms
are essential for a recording of the low-amplitude bio-signals. The (mode dependent) low power consumption of 0.37 µW to 1 µW of the Bio-AFE from a 1 V supply enables battery- or RF-powered applications, which allows new possibilities of bio-signal based tests while treating patients with neurological disorders.