An 8-Channel 1.76-mW 4.84-mm2 Electrical Impedance Tomography SoC with Direct IF Frequency Division Multiplexing

This paper presents an 8-channel EIT SoC for lung image recovery based on direct IF FDM technique. The bio impedance of each channel measured through high frequency current injection is directly chopped down to different low IF frequencies. This allows the combined multi-channel input signals to subsequently share CCIAs, PGA, BUF and ADC. This SoC achieves a maximum frame rate of 12.0 fps for image recovery with the smallest area per channel of 0.61 mm2, a low power of 0.220 mW per channel and an input referred noise of 3.2 μVrms. This SoC is fabricated in 130-nm CMOS process.