A 56MΩ CMOS TIA for MEMS applications

We present the analysis, design, and measurement results of a high-gain, low-noise differential transimpedance amplifier (TIA) designed to interface with electrostatic microelectromechanical systems (MEMS) resonators. A capacitive-feedback current amplifier drives current into an active load to obtain a 56 MOmega transimpedance gain, 1.8 MHz bandwidth, phase response near 0deg, and 65 fA/radicHz input-referred noise. The TIA was fabricated in 0.18 mum CMOS technology and dissipates 436 muW from a 1.8 V supply.