Patent ID: 6028487
Filing Date: 2000-02-22
Classification: H03F

Abstract:
A negative-feedback amplifier circuit for amplifying an input electric signal into an output electric signal, comprising:a plurality of active elements in cascode connection, said active elements including a first-stage active element and a final-stage active element each of which comprises an element input terminal, an element output terminal, and an element control terminal, said element control terminal of the first-stage active element being supplied with said input electric signal, said element output terminal of the final-stage active element outputting said output electric signal;a first negative-feedback circuit connected between said element output terminal of the final-stage active element and said element control terminal of the first-stage active element, said first negative-feedback circuit including a means for adjusting an output impedance of said negative-feedback amplifier circuit; anda second negative-feedback circuit connected between said element output terminal of the first-stage active element and said element control terminal of the first-stage active element,wherein said first negative-feedback circuit returns negative feedback to said element control terminal of the first-stage active element without limiting said negative feedback to a predetermined range of frequencies.