TIGER: a custom readout electronics for the BESIII CGEM detector

TIGER (aka Torino Integrated Gem Electronics for Readout) is the ASIC designed at INFN-Torino for the front-end electronics of a cylindrical triple GEM detector, proposed to replace the inner tracker of BESIII spectrometer (Beijing Electron Spectrometer). The high luminosity of the collider, operational at the Institute of High Energy Physics in Beijing (IHEP), allows to measure states of charmonium and open charm, to carry out light hadrons spectroscopy and to study $\tau$ lepton physics, but it caused aging and degradation problems to the tracking performance. The 64-channel chip in analog-digital mixed mode has been designed using CMOS 110 nm UMC technology in order to be exported to China. Each channel has two branches: branch E for charge measurements and branch T for time measurements.