HGCROC3: the front-end readout ASIC for the CMS High Granularity Calorimeter
F. Bouyjou, G. Bombardi, F. Dulucq, A. El Berni, S. Extier, M. Firlej, T. Fiutowski, F. Guilloux, M. Idzik, C. De La Taille, A. Marchioro, A. Molenda, J. Moroń, K. Świentek, D. Thienpont, T. Vergine
Abstract
Abstract For the CMS High Granularity Calorimeter (CE), the final version of the 72-channel front-end ASIC (HGCROC3) was submitted in December 2020. HGCROC3 includes low-noise/high-gain preamplifiers/shapers and a 10-bit 40 MHz successive approximation ADC (SAR-ADC) that provide the charge measurement over the linear range of the preamplifier. In the saturation range, a discriminator and a time-to-digital converter (TDC) provide the charge information from the time over threshold (ToT; 200 ns dynamic range, 50 ps binning). A fast discriminator and another TDC provide timing information to 25 ps accuracy. The chip embeds all necessary ancillary services: bandgap circuit, PLL, threshold DACs. We present the experimental results on the latest and final version (HGCROC3) received in April 2021.