The STAR cluster-finder ASIC

The STAR experiment reads out a TPC (Time Projection Chamber) and an SVT (Silicon Vertex Tracker), both of which require on-line pedestal subtraction, compression of ADC values from 10-bit to 8-bit, and location of time sequences representing responses to charged-particle tracks. The STAR cluster finder ASIC responds to all of these needs. Pedestal subtraction and compression are performed using lookup tables in attached RAM. We describe the design and implementation of the ASIC, as well as testing methodology and results of tests performed on foundry prototypes.