Regulated Common-Gate TIA with Noise Improvement for Radiation Detectors

A Transimpedance Amplifier (TIA) is a device which performs current-voltage conversion and signal shaping. The most commonly used solution is an Avalanche Photo-Diode (APD) as radiation detector with a feedback TIA. Recently, Silicon Photo-Multipliers (SiPMs), have proven to be good alternatives. The main objective in this paper is to show, evaluate and compare the behavior of a regulated common-gate (RCG) TIA when the light sensitive device is an APD or a SiPM. We will also present two alternative circuits based on the RCG topology. The first can be resumed to the insertion of a transistor, responsible for an improvement in the output noise response of the TIA. This solution proves itself to be a good alternative, since it will improve the Signal-to-Noise Ratio (SNR) of the circuit by around 3 dB, with negligible penalty in consumption (only 2%). The second alternative will be a proposed differential version of the RCG topology, in which the first solution will be included. These two latter solutions will only be tested with a SiPM at the input. We will also study the RCG topology in a RF front-end, providing there is a passive mixer at the TIA’s input. The proposed circuits are simulated with standard CMOS technology (UMC 130 nm), from a 1.2 V supply.