the noise histogram represents the total noise of the readout
chain including the 1/ f and thermal noise. Additionally, the
estimation of the input-referred 1/f noise is based on the
simulated values of the capacitances connected to the sense
node. These values depend on the layout and the process,
hence it was expected to obtain values slightly different
from the calculation and simulation. Fig. 14 shows the inputreferred
noise for the two column level gains. It shows a
large noise increase in the ×1 gain configuration as the
bandwidth becomes much larger (more thermal noise) and all
the noise sources after the column-level amplifier are no longer
negligible. Thanks to the high column level gain of ×64,
the noise originating from the output buffers and analog to
digital conversion is completely negligible. For the 1/f noise,
the contribution of the column level amplifier is negligible
compared to that of the in pixel source follower. For thermal
noise, the column level amplifier contribution is 0.16 e−
rms
which represents 56% of the total thermal noise and 14% of
the total measured noise.