A pixel in a photo sensor, comprising: a portion of a first substrate including a photodiode, a floating diffusion point, a first transistor between the photo diode and the floating diffusion point to transfer charge from the photodiode to the floating diffusion point responsive to turning on the first transistor, a first reset transistor (T RST1) configured to reset a voltage to a first reset voltage (V RST1) at the floating diffusion point responsive to turning on the first reset transistor (T RST1) after an exposure period, and an amplifier (T s) to output the first reset voltage (V RST1) or a signal voltage (V SIG) based on an amount of charge transferred from the photodiode to the floating diffusion point; a portion of a second substrate including a current source (T cs), a pixel level interconnect between the amplifier (T s) and the current source (T CS), a first capacitor, and a first switch selectively coupling the first capacitor to the pixel level interconnect such that the first capacitor is configured to store the signal voltage (V SIG) responsive to turning on the first switch, the second substrate overlapping the first substrate, the current source (T cs) being configured to supply a current to the amplifier (T s) via the pixel level interconnect, wherein the portion of the second substrate further comprises a conductive line, a second capacitor, and a second switch arranged in series with the first switch between the pixel level interconnect and a group comprising the second capacitor and the conductive line, the second capacitor being configured to store the first reset voltage (V RST1) responsive to turning on the second switch while the first switch is on, the conductive line being coupled with the second capacitor and being selectively coupled to the pixel level interconnect through the first switch and the second switch. a portion of a first substrate including a photodiode, a floating diffusion point, a first transistor between the photo diode and the floating diffusion point to transfer charge from the photodiode to the floating diffusion point responsive to turning on the first transistor, a first reset transistor (T RST1) configured to reset a voltage to a first reset voltage (V RST1) at the floating diffusion point responsive to turning on the first reset transistor (T RST1) after an exposure period, and an amplifier (T s) to output the first reset voltage (V RST1) or a signal voltage (V SIG) based on an amount of charge transferred from the photodiode to the floating diffusion point; a portion of a second substrate including a current source (T cs), a pixel level interconnect between the amplifier (T s) and the current source (T CS), a first capacitor, and a first switch selectively coupling the first capacitor to the pixel level interconnect such that the first capacitor is configured to store the signal voltage (V SIG) responsive to turning on the first switch, the second substrate overlapping the first substrate, the current source (T cs) being configured to supply a current to the amplifier (T s) via the pixel level interconnect, wherein the portion of the second substrate further comprises a conductive line, a second capacitor, and a second switch arranged in series with the first switch between the pixel level interconnect and a group comprising the second capacitor and the conductive line, the second capacitor being configured to store the first reset voltage (V RST1) responsive to turning on the second switch while the first switch is on, the conductive line being coupled with the second capacitor and being selectively coupled to the pixel level interconnect through the first switch and the second switch.