  Active pixel sensors based on the High-Voltage CMOS technology are being
investigated as a viable option for the future pixel tracker of the ATLAS
experiment at the High-Luminosity LHC. This paper reports on the testbeam
measurements performed at the H8 beamline of the CERN Super Proton Synchrotron
on a High-Voltage CMOS sensor prototype produced in 180 nm AMS technology.
Results in terms of tracking efficiency and timing performance, for different
threshold and bias conditions, are shown.
