VFAT2 : A front-end “system on chip” providing fast trigger information and digitized data storage for the charge sensitive readout of multi-channel silicon and gas particle detectors.

The architecture, key design parameters and results for a highly integrated front-end readout system fabricated as a single ASIC are presented. The chip (VFAT2) comprises complex analog and digital functions traditionally designed as separate components. VFAT2 contains very low noise 128 channel front-end amplification with programmable internal calibration, intelligent “fast OR” trigger building outputs, digital data tagging and storage, data formatting and data packet transmission with error protection. VFAT2 is designed to work in the demanding radiation environments posed by modern high energy physics experiments, in particular the Large Hadron Collider at CERN. Measured results are presented demonstrating full functionality and excellent analog performance despite intensive digital activity on the same piece of silicon.