Supply circuits, devices and methods related to radio-frequency amplifiers. In some embodiments, an amplification system can include an amplifier circuit having a plurality of stages and configured to amplify a signal. The amplification system can further include a supply circuit configured to provide a regulated supply voltage to at least one stage of the plurality of stages, and an unregulated supply voltage to at least one stage of the plurality of stages. In some embodiments, the amplifier circuit can be implemented as a power amplifier circuit.

A temperature compensation circuit comprises a temperature coefficient circuit that generates a temperature coefficient that is temperature dependent and a compensation circuit that generates a compensation signal based on an indication of temperature of an amplifier and the temperature coefficient, and based on the compensation signal, a gain of the amplifier is adjusted to improve amplifier linearity during data bursts.

A temperature compensation circuit comprises a temperature coefficient circuit that generates a temperature coefficient that is temperature dependent and a compensation circuit that generates a compensation signal based on an indication of temperature of an amplifier and the temperature coefficient, and based on the compensation signal, a gain of the amplifier is adjusted to improve amplifier linearity during data bursts.

A packaged module for use in a wireless communication device has a substrate supporting an integrated circuit die that includes at least a microprocessor and radio frequency receiver circuitry and a stacked filter assembly configured as a filter circuit that is in communication with the radio frequency receiver circuitry. The stacked filter assembly includes a plurality of passive components, where each passive component is packaged as a surface mount device. At least one passive component is in direct communication with the substrate and at least another passive component is supported above the substrate by the at least one passive component that is in the direct communication with the substrate.

A packaged module for use in a wireless communication device has a substrate supporting an integrated circuit die that includes at least a microprocessor and radio frequency receiver circuitry and a stacked filter assembly configured as a filter circuit that is in communication with the radio frequency receiver circuitry. The stacked filter assembly includes a plurality of passive components, where each passive component is packaged as a surface mount device. At least one passive component is in direct communication with the substrate and at least another passive component is supported above the substrate by the at least one passive component that is in the direct communication with the substrate.

Aspects of this disclosure relate to an impedance transformation circuit for use in an amplifier, such as a low noise amplifier. The impedance transformation circuit includes a matching circuit including a first inductor. The impedance transformation circuit also includes a second inductor. The first and second inductors are magnetically coupled to each other to provide negative feedback to linearize the amplifier.

Aspects of this disclosure relate to an impedance transformation circuit for use in an amplifier, such as a low noise amplifier. The impedance transformation circuit includes a matching circuit including a first inductor. The impedance transformation circuit also includes a second inductor. The first and second inductors are magnetically coupled to each other to provide negative feedback to linearize the amplifier.

In a portable radio transceiver, a power amplifier system includes a saturation detector that detects power amplifier saturation in response to duty cycle of the amplifier transistor collector voltage waveform. The saturation detection output signal can be used by a power control circuit to back off or reduce the amplification level of the power amplifier to avoid power amplifier control loop saturation.

In a portable radio transceiver, a power amplifier system includes a saturation detector that detects power amplifier saturation in response to duty cycle of the amplifier transistor collector voltage waveform. The saturation detection output signal can be used by a power control circuit to back off or reduce the amplification level of the power amplifier to avoid power amplifier control loop saturation.

Certain aspects of the present disclosure are directed to a digital predistortion (DPD) device for use within a wireless transmitter that permits the use of a downstream digital-to-analog converter that operates at a clock rate close to the bandwidth of a digital baseband input signal. In some examples, a sampling rate of a digital baseband input signal is increased using an upsampler to obtain an increased rate digital input signal. Predistortion is applied to the increased rate digital input signal using a DPD device to obtain a predistorted digital signal. The sampling rate of the predistorted digital signal is then decreased using a downsampler to obtain a lower-rate predistorted digital signal with a sampling rate below the increased rate of the upsampler (e.g. close to the bandwidth of a digital baseband input signal). A low pass filter may be provided to filter out-of-band signal components from the predistorted digital signal.