  Monolithic CMOS pixel detectors have emerged as competitive contenders in the
field of high-energy particle physics detectors. By utilizing commercial
processes they offer high-volume production of such detectors. A series of
prototypes has been designed in a 180$\,$nm Tower process with depletion of the
sensor material and a column-drain readout architecture. The latest iteration,
TJ-Monopix2, features a large 2$\,$cm x 2$\,$cm matrix consisting of 512 x 512
pixels with 33.04$\,$um pitch. A small collection electrode design aims at low
power consumption and low noise while the radiation tolerance for high-energy
particle detector applications needs extra attention. With a goal to reach
radiation tolerance to levels of $10^{15}\,1\,$MeV n$_\text{eq}\,$cm$^{-2}$ of
NIEL damage a modification of the standard process has been implemented by
adding a low-dosed n-type silicon implant across the pixel in order to allow
for homogeneous depletion of the sensor volume. Recent lab measurements and
beam tests were conducted for unirradiated modules to study electrical
characteristics and hit detection efficiency.
