Cathode Comparator ASIC

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Links:

Complete description: Trigger TDR Chapter 11

Details for the pre-production version of the Comparator ASIC:

Cathode Comparator ASIC "COMP-C" and board-level schematics (1999)

Details for previous versions of the Comparator ASIC:

Cathode Comparator ASIC "COMP-B" and associated Comparator Board (1998)

Cathode Comparator ASIC "COMP-A" (1997)

General Description:

The CSC local trigger localizes the muon track to one-half of a strip width in each cathode layer. This is done with a 16-channel 'comparator' ASIC that inputs amplified and shaped signals and compares the charges on all adjacent and next-to-adjacent strips.

If a strip charge is found to be larger than those on its neighbors, a hit is assigned to the strip. Simultaneous comparison of left versus right neighbor strip charges allows assignment of the hit to the right or left side of the central strip, effectively doubling the resolution.

Performance:

Various test beam studies were done on the comparator ASICs before settling on "version 3" for actual use in CMS. Some of the results of these studies are described in a talk given in November, 2000.