LF-MightyPix: A second HV-MAPS prototype for the LHCb Mighty-Tracker

For the future high-luminosity operation of the LHCb experiment, the downstream tracker will be upgraded to the Mighty-Tracker. A key part of this upgrade is the introduction of silicon pixel detectors, MightyPix, in the central region of the tracker. We have developed MightyPix prototype chips using High-Voltage Monolithic Active Pixel Sensors fabricated in a commercially available CMOS process on high-resistivity wafers. The second prototype chip, LF-MightyPix, is fabricated in the LFoundry 150 nm CMOS process. LF-MightyPix has a chip size of 3.5 mm x 4.0 mm and a pixel size of 100 µm x 100 µm. For each pixel hit, both the time of arrival and the time over threshold are recorded to ensure correct bunch-crossing identification at 40 MHz. The results presented in this paper confirm compatibility with the MightyPix requirements.