  We have been developing monolithic active pixel sensors, named ``XRPIX'',
based on the silicon-on-insulator (SOI) pixel technology for future X-ray
astronomy satellites. XRPIX has the function of event trigger and hit address
outputs. This function allows us to read out analog signals only of hit pixels
on trigger timing, which is referred to as the event-driven readout mode.
Recently, we processed ``XRPIX5b'' with the largest imaging area of 21.9~mm
$\times$ 13.8~mm in the XRPIX series. X-ray spectra are successfully obtained
from all the pixels, and the readout noise is 46~e$^-$~(rms) in the frame
readout mode. The gain variation was measured to be 1.2\%~(FWHM) among the
pixels. We successfully obtain the X-ray image in the event-driven readout
mode.
