  The CERN-RD50 CMOS working group develops the RD50-MPWseries of monolithic
high-voltage CMOS pixel sensors for potential use in future high luminosity
experiments such as the HL-LHC and FCC-hh. In this contribution, the design of
the latest prototype in this series, RD50-MPW3, is presented. An overview of
its pixel matrix and digital readout periphery is given, with discussion of the
new structures implemented in the chip and the problems they aim to solve. The
main analog and digital features of the sensor are already tested and initial
laboratory characterisation of the chip is presented.
