摘要 |
A variable gain amplifying device that amplifies an input signal and outputs the amplified signal, has a controlling circuit that controls the gain by controlling turning on and off of first MOS transistors and third MOS transistors so that the sum of the number of first MOS transistors turned on and the number of third MOS transistors turned on is "n" by outputting a control signal to the gates of the first MOS transistors and the third MOS transistors.
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