| 摘要 |
PURPOSE: To obtain OTA capable of executing a low voltage operation whereby the linearity of transconductance is improved over a wide input voltage range which is generated in a semi-conductor integrated circuit. CONSTITUTION: The transconductance of a differential pair 101 is reduced in accordance with the increase of an input voltage VIN. When the differential pari 10-1 is a bipolar differential pair Q1 and Q2 which is driven by constant current by commonly being connected to an emitter, the collector current Ic1 of a transistor Q1 is turned back at a first current mirror circuit 103 and taken- out as differential output currentΔIc. When a square characteristic is given to the driving current IEE of the transistors Q1 and Q2, the linearity of the transconductance is improved. Then, current I<-> being one of the differential output currents of a square circuit 102 is permitted to flow in the constant current source of the differential pair 101 so that the effective driving current IEE of the differential pair 101 becomes the one obtained by subtracting I<-> from current IT.
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