Current mode charge sensitive amplifying technique providing noise performance independent of the radiation detector capacitance

Abstract

Alternative current mode charge sensitive amplifier (CSA) topology and related methodology for use as pre-amplification block in radiation detection read out front end IC systems is proposed. It is based on the use of a suitably configured current conveyor architecture providing advantageous noise performance characteristics in comparison to the traditionally used CSA structures. In the proposed architecture the noise at the output of the CSA is independent of the detector capacitance value, allowing the use of large area detectors without affecting the system noise performance. Theoretical analysis and simulation based results are performed concerning the operation - performance of the proposed topology. Measurement results on a current mode CSA prototype fabricated with a 0.35 µm CMOS process by Austriamicrosystems are provided supporting the theoretical and simulation results and confirming the advantageous performance in relation to the traditional voltage mode structures mainly in terms of the noise performance dependency on the detector capacitance value.