TY - JOUR
T1 - A 1.9 e- random noise CMOS image sensor with active feedback operation in each pixel
AU - Lee, Woonghee
AU - Akahane, Nana
AU - Adachi, Satoru
AU - Mizobuchi, Koichi
AU - Sugawa, Shigetoshi
PY - 2009/11/10
Y1 - 2009/11/10
N2 - A 1.9 e- random noise CMOS image sensor has been developed by applying an active feedback operation (AFO), which uses a capacitive feedback effect to floating diffusion (FD) by a gate-source capacitance of a pixel source follower (SF), in a CMOS image sensor with a lateral overflow integration capacitor (LOFIC) technology. It is described that the AFO is suitable for CMOS image sensors with LOFIC because the design of the full well capacity and the FD can be independently optimized. The AFO theory is found to be explored to a large signal voltage in detail, as well as the conventional analysis of the capacitive feedback effect of the pixel SF for a small signal voltage. A 1/4-in 5.6-μm-pitch 640(H) × 480(V) pixel sensor chip in a 0.18-μm two-poly-Si three-metal CMOS technology achieves about 1.7 times the sensitivity with AFO compared with the case where the feedback operation is not positively used, resulting in an input-referred conversion gain of 210 μV/e- and an input-referred noise of 1.9 e-. A high well capacity of 130000 e- is also achieved.
AB - A 1.9 e- random noise CMOS image sensor has been developed by applying an active feedback operation (AFO), which uses a capacitive feedback effect to floating diffusion (FD) by a gate-source capacitance of a pixel source follower (SF), in a CMOS image sensor with a lateral overflow integration capacitor (LOFIC) technology. It is described that the AFO is suitable for CMOS image sensors with LOFIC because the design of the full well capacity and the FD can be independently optimized. The AFO theory is found to be explored to a large signal voltage in detail, as well as the conventional analysis of the capacitive feedback effect of the pixel SF for a small signal voltage. A 1/4-in 5.6-μm-pitch 640(H) × 480(V) pixel sensor chip in a 0.18-μm two-poly-Si three-metal CMOS technology achieves about 1.7 times the sensitivity with AFO compared with the case where the feedback operation is not positively used, resulting in an input-referred conversion gain of 210 μV/e- and an input-referred noise of 1.9 e-. A high well capacity of 130000 e- is also achieved.
KW - CMOS image sensor
KW - Full well capacity (FWC)
KW - Low noise
KW - Signal-to-noise ratio (SNR)
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U2 - 10.1109/TED.2009.2030644
DO - 10.1109/TED.2009.2030644
M3 - Article
AN - SCOPUS:70350724634
VL - 56
SP - 2436
EP - 2445
JO - IEEE Transactions on Electron Devices
JF - IEEE Transactions on Electron Devices
SN - 0018-9383
IS - 11
ER -