Performances of the Coincidence Matrix ASIC of the ATLAS Barrel Level-1 Muon Trigger

The ATLAS Barrel Level-1 muon trigger handles data coming from the Resistive Plate Chamber detectors, structured in three concentric layers inside the air-core barrel toroid. The trigger classifies muons within different programmable transverse momentum thresholds, and tags the identified tracks with the corresponding bunch crossing number. The algorithm looks for hit coincidences within different detector layers inside the programmed geometrical road which defines the transverse momentum cut. The Coincidence Matrix ASIC implements the trigger algorithm and the readout of the RPC detector, processing hit signals coming from up to four detector layers. It finds muon track candidates and generates the output trigger patterns with a latency of a few 25 ns bunch crossing periods, and produces and time tags the readout hit patterns. Due to the different performance needs and limitations in the maximum power dissipation and technology, the CMA input pipeline and trigger logic and the time interpolator run at the working frequency of 320 MHz, the readout part works at 160 MHz while the control part works at 40 MHz. Performances of the ASIC have been studied on different test station, the test results are presented.