Design and results from the APV25, a deep sub-micron CMOS front-end chip for the CMS tracker

The APV25 is a 128-channel analogue pipeline chip for the readout of silico n microstrip detectors in the CMS tracker at the LHC. Each channel comprise s a low noise amplifier, a 192-cell analogue pipeline and a deconvolution r eadout circuit. Output data are transmitted on a single differential curren t output via an analogue multiplexer. The chip is fabricated in a standard 0.25 mum CMOS process to take advantage of the radiation tolerance, lower n oise and power. and high circuit density. Experimental characterisation of this circuit shows full functionality and good performance both in pre- and post-irradiation (20 Mrad) conditions. The measured noise is significantly reduced compared to earlier APV versions. A description of the design and results from measurements prior to irradiation are presented. (C) 2001 Else vier Science B.V. All rights reserved.