Shunt-Shunt Feedback Inverter Transimpedance Amplifier Design for Capsule Endoscopy

This work reports on the design and performance of a shunt-shunt feedback inverter transimpedance amplifier (TIA). The proposed design is to be employed in capsule endoscopy with optical imaging or similar biomedical systems. The design is implemented in 180 nm CMOS technology with the performance targets of low area, low power, low complexity, high gain, and low noise. Alternative feedback resistor design approaches are proposed to achieve lower dispersion in transimpedance gain (TI gain), where one of the approaches proves superior in terms of area and performance. The design achieves 96 dBΩ gain with sub-0.6 dBΩ standard deviation in post-layout Monte Carlo simulations. The total input capacitance is 10 pF (from the photodiode), and the achieved -3 dB cut-off frequency is 50 MHz. The achieved total integrated input noise is 0.63 μA, and the total power consumption is 0.26 mW. Compared to similar works, the design improves power consumption and complexity without losing noise, and the TI gain performance considerably by keeping a narrow bandwidth, which is sufficient for the target operation.