Programmable Low-Power Low-Noise Capacitance to Voltage Converter for MEMS Accelerometers

In this work, we present a capacitance-to-voltage converter (CVC) for capacitive accelerometers based on microelectromechanical systems (MEMS). Based on a fully-differential transimpedance amplifier (TIA), it features a 34-dB transimpedance gain control and over one decade programmable bandwidth, from 75 kHz to 1.2 MHz. The TIA is aimed for low-cost low-power capacitive sensor applications. It has been designed in a standard 0.18-mu m CMOS technology and its power consumption is only 54 mu W. At the maximum transimpedance configuration, the TIA shows an equivalent input noise of 42 fA/root Hz at 50 kHz, which corresponds to 100 mu g/root Hz.