Semiconductor device and communication device comprising the same

A semiconductor device, comprising:

• a first amplification circuit configured to output a first amplification signal and a second amplification signal by amplifying a first input signal and a second input signal;
• a second amplification circuit including a first amplification transistor turned on based on the first amplification signal to generate a first output signal, a second amplification transistor turned on based on the second amplification signal to output a second output signal, and a first bias transistor turned on based on a first bias signal to generate the first output signal;
• a first bias capacitor connected to the first amplification transistor and the first bias transistor;
• a first switch circuit configured to provide one of a bias voltage and the first amplification signal to one end of the first bias capacitor;
• and
• a common mode feedback circuit configured to receive the first and second output signals and output a feedback signal that adjusts an average of the first and second output signals to correspond to a reference signal, to the first amplifier.

A communication device, comprising:

• a trans-impedance amplifier configured to amplify first and second input signals from a reception mixer;
• and
• a reception filter configured to filter an output of the trans-impedance amplifier,
• wherein the trans-impedance amplifier comprises:
• a first amplification circuit configured to output a first amplification signal and a second amplification signal by amplifying the first input signal and the second input signal;
• a second amplification circuit including a first amplification transistor turned on based on the first amplification signal to generate a first output signal, a second amplification transistor turned on based on the second amplification signal to output a second output signal, and a first bias transistor turned on based on a first bias signal to generate the first output signal;
• a first filter circuit including a first bias capacitor connected to the first amplification transistor and the first bias transistor and configured to generate the first bias signal using a first bias voltage;
• and
• a common mode feedback circuit configured to receive the first and second output signals and output a feedback signal that adjusts an average of the first and second output signals to correspond to a reference signal, to the first amplifier,
• wherein the first filter circuit adjusts a voltage of the first bias capacitor such that a first voltage of the first bias capacitor in a disabled state in which the amplifier does not perform an amplification operation corresponds to a second voltage of the first bias capacitor in an enabled state in which the amplifier performs the amplification operation.