Active load circuit for low-voltage CMOS voltage gain amplifier with wide bandwidth and high gain characteristic

摘要

Provided is an active load circuit of a voltage gain amplifier, which allows a high voltage gain with a low supply voltage operation in high-frequency range. The active load circuit includes a PMOS transistor which is connected between the amplifying unit and a power supply voltage and functions as a load element in a low frequency range; a negative feedback buffering unit which is connected to the gate of the PMOS transistor and functions as a common drain amplifier to stabilize the output voltage of the voltage gain amplifier and drive the voltage gain amplifier at a low voltage; and a capacitor which is connected to the negative feedback buffering unit and compensates for both an impedance and a frequency characteristics when the voltage gain amplifier operates in a high frequency range.