AMPLIFIER CIRCUIT AND TRANSIMPEDANCE AMPLIFIER

摘要

PROBLEM TO BE SOLVED: To obtain a flat frequency characteristic having no excessive peaking even if a gain is switched with respect to a variable gain type amplifier to be used for an optical reception circuit. SOLUTION: A current source circuit 3 is connected to an output terminal OUTa of an emitter grounding circuit 1A outputting an amplification signal S, and a bias current to be supplied to an input stage transistor of the emitter grounding circuit 1A is shunted to the current source circuit 3. In this case, the size of the current to be shunted is controlled in accordance with the gain of the amplifier circuit 10A selected in a gain switching circuit 20. COPYRIGHT: (C)2007,JPO&INPIT