Abstract: An operational amplifier includes a first amplifying unit, a second amplifying unit, a current source, a first compensation capacitor, and a second compensation capacitor. The first amplifying unit includes a first input transistor, a second input transistor, a third input transistor, and a fourth input transistor. The second amplifying unit includes a fifth input transistor, a sixth input transistor, a seventh input transistor, and an eighth input transistor. One end of the first compensation capacitor is coupled to a drain of the seventh input transistor, and the other end of the first compensation capacitor is coupled to a gate of the eighth input transistor. One end of the second compensation capacitor is coupled to a drain of the eighth input transistor, and the other end of the second compensation capacitor is coupled to a gate of the seventh input transistor.

Abstract: An operational amplifier includes a first amplifying unit, a second amplifying unit, a current source, a first compensation capacitor, and a second compensation capacitor. The first amplifying unit includes a first input transistor, a second input transistor, a third input transistor, and a fourth input transistor. The second amplifying unit includes a fifth input transistor, a sixth input transistor, a seventh input transistor, and an eighth input transistor. One end of the first compensation capacitor is coupled to a drain of the seventh input transistor, and the other end of the first compensation capacitor is coupled to a gate of the eighth input transistor. One end of the second compensation capacitor is coupled to a drain of the eighth input transistor, and the other end of the second compensation capacitor is coupled to a gate of the seventh input transistor.

Abstract: Aspects of the disclosure provide an operational transconductance amplifier (OTA) having an output stage. The output stage includes a first amplifier path configured to drive a first output current from a first power supply and a first resistor coupled between the first power supply and a source terminal of a first transistor in the first amplifier path. The first resistor is configured to improve a linearity of the OTA.

Abstract: Aspects of the disclosure provide a circuit having a filter circuit and a controller. The filter circuit drives a load circuit having different input impedances under different operation conditions. The filter circuit is configured to have a first output circuit coupled with a first resistor and a second output circuit coupled with a second resistor. The controller is configured to generate control signals to select one of the first output circuit and the second output circuit based on an operation condition of the load circuit.

Abstract: System and methods are provided for reducing signal distortion in wireless communication. An example system includes: an up-converter configured to generate a radio frequency signal based at least in part on a baseband signal for wireless communication and an oscillation signal; an amplifier configured to amplify the radio frequency signal and generate a transmission signal, the transmission signal including a first counter-intermodulation component associated with the up-converter and a second counter-intermodulation associated with the amplifier; and a signal generator configured to output a distortion-cancellation signal to the up-converter to reduce signal distortion associated with the first counter-intermodulation component and the second counter-intermodulation component.

Abstract: System and methods are provided for reducing signal distortion in wireless communication. An example system includes: an up-converter configured to generate a radio frequency signal based at least in part on a baseband signal for wireless communication and an oscillation signal; an amplifier configured to amplify the radio frequency signal and generate a transmission signal, the transmission signal including a first counter-intermodulation component associated with the up-converter and a second counter-intermodulation associated with the amplifier; and a signal generator configured to output a distortion-cancellation signal to the up-converter to reduce signal distortion associated with the first counter-intermodulation component and the second counter-intermodulation component.