All-programmable low noise readout ASIC for silicon strip sensors in tracking detectors

Abstract

The Programmable Read-out with Improved Noise-performance Charge Sensitive Amplifier (PRINCSA) is a prototype Application Specific Integrated Circuit (ASIC) designed for read-out of the silicon micro-strip sensors in the tracking detectors for Physics experiments. The main aim of this project was to minimize the overall system noise (Equivalent Noise Charge, ENC) and implement a range of programmable features to adjust the noise performance to varying conditions. The chip comprises three single-ended and three pseudo-differential channels that additionally allow for power supply interference reduction. All channels include a charge sensitive amplifier (CSA), a fast shaping amplifier for time measurements, and a slow shaping amplifier for amplitude measurements. The slow shaper’s architecture (in all channels) and its peaking time (in the single-ended channels) are configurable to test the capability of noise filtering for various dominant noise contributions (unipolar semi-Gaussian and complex conjugate poles filters). To further improve the power supply rejection ratio, additional on-chip filtering of the preamplifier biasing potential is included in every channel. For faster CSA baseline restoration, its feedback in all channels is equipped with a pulsed reset circuit. In this design, it is combined with a double-polarity Krummenacher circuit for leakage current compensation for both polarities of charge pulse and leakage current without compromising the large value of the CSA feedback resistance. The ASIC comprises a calibration circuit working in two operational modes: a standard double-polarity charge injection and a single-polarity charge injection (fast leading and slow falling edges of the calibration pulses) with programmable amplitude. The IC was fabricated in Q4 2018 using UMC CMOS 180 nm technology node.