Patent ID: 7940121

Claim:
An operational amplifier comprising: an element formation layer including a differential section for converting a differential voltage composed of first and second input voltages to a current pair, a current adjustment section for adjusting the current amount supplied to the differential section, and an active load section for receiving the current pair from the differential section; and an interconnect layer formed on the element formation layer, the interconnect layer including first and second differential voltage interconnects and first and second bias voltage interconnects, wherein the differential section includes a plurality of first and second differential transistors having a first polarity, the current adjustment section includes a plurality of current source transistors having the first polarity, the active load section includes a plurality of first and second load transistors having a second polarity reverse to the first polarity, the first differential voltage interconnect electrically connects a gate electrode of a transistor to be used among the plurality of first differential transistors to a first input node receiving the first input voltage, the second differential voltage interconnect electrically connects a gate electrode of a transistor to be used among the plurality of second differential transistors to a second input node receiving the second input voltage, the first bias voltage interconnect electrically connects a gate electrode of a transistor to be used among the plurality of current source transistors to a first bias node receiving a first bias voltage for turning ON a transistor having the first polarity, and the second bias voltage interconnect electrically connects gate electrodes of transistors to be used among the plurality of first and second load transistors to a second bias node receiving a second bias voltage for turning ON a transistor having the second polarity.