VARIABLE GAIN AMPLIFIER

摘要

A variable gain amplifier is provided to offer a constant output level by adjusting currents for respective stages while maintaining a constant bandwidth and a constant gain. A variable gain amplifier includes first to sixth modules. The first module(100) receives first and second differential input signals. The second module(150) adjusts a plurality of discontinuously inputted currents to the current of a mirror type and changes the current flowing from the first module. The third module(200) is series-connected to the first module and amplifies two differential signals from the first module. The fourth module(250) adjusts plural discontinuous currents to the current of a mirror type and changes the current flowing from the third module. The fifth module(300) feeds back the output from the third module to an input terminal. The sixth module(350) adjusts plural discontinuous input currents to the current of a mirror type and changes the current flowing from the fifth module.