Attenuator with switch function and mobile telephone terminal device using the same

摘要

A high frequency part, which amplifies a high frequency signal outputted from an intermediate frequency part and supplies to an antenna, is equipped with a gain controller with switch function. The gain controller with switch function comprises an attenuator with switch function has a function of switching a selected band between two bands outputted from the intermediate frequency part and controlling the gain of the high frequency signal in the selected band. The attenuator with switch function comprises a first variable resistor which connects a signal input part with a signal output part and a second variable resistor which is disposed parallel to said first variable resistor and connects a signal input part with a signal output part. The first and the second variable resistors are controlled by a common gain control voltage and set such that the gain control voltage ranges, which are for changing the resistor values, will not overlap with each other.