Amplifiers and transceiver devices using the same

A transceiver device operating in a test mode and a normal mode, comprising:

• an antenna unit for receiving a radio frequency input signal to generate a pair of input signals and receiving a pair of output signals to generate an RF output signal;
• a transmitter having a pair of first differential output terminals coupled to the antenna unit, respectively, at a first common node and a second common node, and providing the pair of output signals;
• an amplifier having a pair of first differential input terminals coupled to the antenna unit, respectively, at the first and second common nodes, for receiving the pair of input signals and performing an amplifying operation on the pair of input signals;
• a receiver mixing unit, having a pair of second differential input terminals coupled to the amplifier, for receiving the pair of amplified input signals from the amplifier;
• and
• a loopback path circuit coupled between the first and second common nodes and the pair of second differential input terminals of the receiver mixing unit,
• wherein the amplifier comprises:
• a pair of first input transistors coupled between a pair of first differential nodes and a reference voltage source, for receiving the pair of input signals;
• a first load coupled to the pair of first differential nodes and a pair of second differential output terminals of the amplifier;
• and
• a first canceling circuit, coupled between the first differential nodes, for balancing voltages, respectively, at the first differential nodes when the transceiver device operates in the test mode.