Patent ID: 6549073
Filing Date: 2003-04-15
Classification: H03F

Abstract:
A differential amplifier circuit, comprisinga first metal oxide silicon field effect transistor and a second metal oxide silicon field effect transistor whose sources are differentially connected to each other; a constant current source connected to the sources of said first and said second transistor producing a first common impedance; a third metal oxide silicon field effect transistor having a first drain voltage; a fourth metal oxide silicon field effect transistor having a second drain voltage; a second adjustable impedance, a first balancing circuit being electrically connected to said third transistor, said fourth transistor and said second adjustable impedance; said third and said fourth transistors being responsive to said first balancing circuit for causing said second adjustable impedance to have a polarity opposite said first common impedance wherein varying said second adjustable impedance changes said differential amplifier's circuit's common-mode gain.