| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a new device for enhancing P1 dB characteristics of a differential amplifier circuit. Ž<P>SOLUTION: A differential amplifier circuit includes: first and second transistors Tr1 and Tr2 connected to first and second differential inputs, respectively; a first cascode transistor CT1 disposed between the first transistor and a first differential output; a second cascode transistor CT2 disposed between the second transistor and a second differential output; a third transistor Tr3 including a control terminal connected to control terminals of the first and second transistors; a third cascode transistor CT3 including a control terminal connected to control terminals of the first and second cascode transistors; and a detection circuit 101 for detecting amplitudes of differential input signals input from the first and second differential inputs and controlling a gate voltage or base current of the first to third cascode transistors according to the detected amplitudes. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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