| 摘要 |
PURPOSE:To realize a low voltage of a power-supply voltage without damaging a dynamic range and the linearity of an output by a method wherein a threshold voltage of a driving MOS transistor inside an output circuit is set to a highest value among MOS transistors of an identical conductivity type formed on an identical substrate. CONSTITUTION:This device is composed of an enhancement-type driving MOS transistor 21 whose gate is connected to a floating diffusion region 16 and an electric current source which is connected to a source of the MOS transistor 21; it is equipped with a source follower type output circuit 20 which converts a stored electric charge of the floating diffusion region 16 into a voltage value and then outputs a converted value. A threshold voltage of the driving MOS transistor 21 inside the output circuit 20 is set to a highest value among MOS transistors of an identical conductivity type formed on an identical substrate. Because the threshold voltage of the driving MOS transistor 21 inside the output circuit 20 is set to be big, this transistor can be operated in a saturation region even when a reset voltage is made high. By this setup, it is possible to realize a low voltage of a power-supply voltage without damaging a dynamic range of an output.
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