An autozeroing inverter based front-end for resonating sensors

Abstract

In this paper we propose a new front-end for resonating sensors which is based on a logic inverter working as amplifier. The front-end is compact and auto-zeroing which makes it a good candidate for integration and for low power applications. It has been simulated in AMS-350nm CMOS Technology and a prototype has been fabricated using discrete components on a PCB. The circuit was tested with a BvD load implemented in discrete components, which can be proved to be a good model for a resonant sensor. The components used to implement the BvD load are: Lm = 3mH, Rb = 200Ω, Cs = 560pF, Ce = 3.3nF which leads to a resonant frequency of 140 KHz. The bandwidth of the amplifier is 380kHz and the mid-band gain is 55V/V. The prototype has been tested with a power supply of 5V.