The ETROC1: The first full chain precision timing prototype for CMS MTD Endcap Timing Layer (ETL) upgrade

<!--HTML-->The Endcap Timing Readout Chip (ETROC) is being developed for the CMS MTD Endcap Timing Layer (ETL) for the HL-LHC, to process LGAD signals with time resolution down to 30ps per track. The ETROC1 is the first full chain precision timing prototype, including preamplifier and discriminator, as well as a new low power TDC design that performs time-of-arrival (TOA) and time-over-threshold (TOT) measurements. It also includes a 4x4 pixel array with precision clock distribution network that is scalable to the final full size 16x16 array. The performance of ETROC1 with bench test and beam test results are presented.