Low Noise-Low Power Transimpedance Amplifier Design for Electric Field Sensing

Two 3V folded-cascode operational amplifiers with low noise and low power consumption were presented. The op-amps are suitable as preamplifiers for an electric field mill sensor interface. The two op-amps differ in their input stages, with the first one having a pmos differential pair and the second one being implemented with a rail-to-rail configuration. A noise optimization was performed for the configurations and was focused on low-frequency domain applications, where flicker noise is the main source of the noise. Advanced simulations were performed and the final circuits of the op-amps were compared in a 0.18 um CMOS process commercially available by XFAB, versus their noise performance and silicon area to cost ratio.