Semiconductor apparatus and communication apparatus

摘要

A first low noise amplifier (LNA 1 111 ) is provided with a control terminal ( 1115 ) for turning of/off the low noise amplifier (LNA 1 111 ). Power terminals of the low noise amplifier (LNA 1 111 ) and a second low noise amplifier (LNA 2 112 ) are commonly connected, and are connected to a power supply ( 10 ) via a power supply switch ( 1114 ). Ground terminals of the two amplifiers (LNA 1 111 ) and (LNA 2 112 ) are commonly connected, and a constant current source ( 1 115 ) is connected between the common terminal and the ground. The amplifiers (LNA 1 111 ) and (LNA 2 112 ) are turned on/off by switching the voltage applied to the control terminal ( 1115 ) of the first low noise amplifier (LNA 1 111 ) between a high potential and a low potential. The power supply switch ( 1114 ) is turned off during signal transmission. Therefore, an LNA block can be provided by using only one power supply switch ( 1114 ), whereby it is possible to reduce the number of devices from that in the prior art, thereby realizing a reduction in the size thereof.