Precision Timing with Low Gain Avalanche Detectors with the CMS Endcap Timing Layer for HL-LHC

The CMS MTD will provide accurate timestamps with a resolution of 30-40 ps for all charged tracks up to a pseudo-rapidity of $\lvert \eta \rvert$=3. This upgrade will mitigate the effects of pile-up expected under the HL-LHC running conditions and bring new and unique capabilities to the CMS detector. The endcap region of the MTD, called ETL, will be instrumented with LGAD sensors, covering the high-radiation pseudo-rapidity region 1.6 $< \lvert \eta \rvert <$ 3.0. The LGADs will be read out with the ETROC readout chip, which is being designed for precision timing measurements. We present recent progress in the characterization of LGAD sensors for the ETL and development of ETROC, including test beam and bench measurements.