High precision injection circuit for in-pixel calibration of a large sensor matrix

This work will discuss the design of a high linearity, low dispersion injection circuit to be used for pixel-level calibration of detector readout electronics. In hybrid pixel detectors, the circuit provides a useful means for precise analog test of the pixel cell unit already at the chip level, when no sensor is connected or the detector has been connected to the chip. Moreover, it provides a simple means for calibration of readout electronics in monolithic active pixel sensors. Two injection techniques were investigated in this paper, one for charge and one for transresistance readout architecture. The aim of the paper is to discuss the design guidelines for the calibration circuit and to present the relevant simulation results of the system, which has been implemented in a 130 nm CMOS technology.