Version 2.2

CMS/TN 95-164

Padova, September 25 1995

Version 2.2

Testing of the 128-PreMux chips

N.Bacchetta, L.Castellani, D.Pantano, C.Pluti

INFN Padova and University of Padova, via Marzolo 8 I35100 Padova-Italy

The 128-PreMux chip is functionally identical to the PreShape32[1,2,3,4] except for having128 channels and a multiplexer for the analogue-out data at a nominal clock speed of1MHz. It also has the possibility of working in double sample mode for baselinesubtraction or to use a 129th channel instead as the baseline for all the other channels.

The testing of the 128-PreMux[5,6] chips is divided into two parts. The first part consists ofa comprehensive test of all the functionality of the chip on a sample of few by bonding thechips on a chip carrier and by using a special board designed in Padova for this purpose.Once few chips have shown to behave accordingly to specs, the second set of tests is aimedmainly to quickly establish the working conditions of the chips and to measure the workingpoints on the bias networks in order to possibly match chips having similar characteristic.This document describes briefly the second set of tests.

It consist of 3 tests:

a.measure of the quiescent points on the bias networkb.same as a. but with the clock of the multiplexer running

c.inject charge through the calibration lines and check the response of each channel.

The setup we have used is shown in fig.1.

fig. 1