Patent ID: 7728667
Filing Date: 2010-06-01
Classification: H03F

Abstract:
1. A differential amplifier comprising: a pair of first emitter-follower transistors for buffering input signals; a pair of voltage drop generation circuits for generating voltage drops dependent upon collector currents at the collectors of the first emitter-follower transistors; a pair of second emitter-follower transistor for buffering output signals of the first emitter-follower transistors; a pair of first amplification transistors which are alternately connected with the first emitter-follower transistors and are driven by the second emitter-follower transistors; a pair of second amplification transistors which are driven by the second emitter-follower transistors, thus providing output signals; a pair of first base-grounded transistors which are inserted between the first emitter-follower transistors and the first amplification transistors; a pair of second base-grounded transistors which are inserted between the second amplification transistors and output terminals; and a bias circuit for supplying each of the first base-grounded transistors and the second base-grounded transistors with a bias voltage, thus setting a same collector-emitter voltage to each of the first emitter-follower transistors and each of the first amplification transistors and the second amplification transistors.