Design of a transimpedance amplifier for broadband current-readout mode magnetic sensors

Modern power electronics applications demand compact and low-power magnetic field sensors with increased bandwidth performance. In this perspective, current-mode readout topologies of magnetic sensors based on a transimpedance amplifier (TIA) were recently proven to be effective solutions. This paper gives an insight into TIA design trade-offs with a specific focus on their application to the readout of magnetic field sensors. Based on this review, the paper details the microelectronic circuit design of a resistive-feedback TIA (R-TIA) specifically tailored for bridge-based resistive magnetic sensors and discusses trade-offs between noise, power, and bandwidth performance. The proposed architecture is fully differential and self-biased, and is implemented in a 90-nm microelectronic process from STMicroelectronics. The developed R-TIA achieves up to 45 MHz bandwidth with a 1.2-V supply, in simulation. Experimental tests of the proposed R-TIA as a current-mode readout for an integrated Hall-effect magnetic sensor are also reported with input signals in the MHz range, proving the suitability of R-TIA for the readout of broadband magnetic sensors.