| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a semiconductor device and an optical reader, capable of handling high-potential signals that exceed breakdown voltage, without making the input signals attenuate, eliminating the need for an attenuator and an amplifier thereafter, or the like, and suppressing increase in area and generation of offsets. Ž<P>SOLUTION: The semiconductor device includes: a drive stage 20 operated by a high power source voltage VDD1; and an input stage 30 connected to the drive stage 20 and operated by a low power source voltage VDD2 that is lower than the high power source voltage VDD1, for inputting signals by the drive stage. The input stage 30 includes: an operational amplifier 33, configured such that positive and negative input terminals become virtually short-circuited; a resistance element R31, connected between a signal input terminal by the drive stage and the node ND31 of the virtual short-circuit; and a diode D31 inserted between the node ND31 of the virtual short-circuit and a power source on the low power source voltage side so that power source is oriented in the forward direction from the node ND31 to the side. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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