A radio-frequency module includes a substrate, a low-noise amplifier circuit being a first amplifier circuit arranged in a first area in the substrate, a power amplifier circuit being a second amplifier circuit arranged in a second area in the substrate, and a duplexer being a component arranged between the first area and the second area in the substrate and having a heat generating property lower than that of the power amplifier circuit. The low-noise amplifier circuit includes a bias circuit configured to generate a bias current dependent on temperature characteristics of a first diode, a voltage generating circuit configured to generate a voltage dependent on temperature characteristics of a second diode as an operating voltage for the bias circuit, and an amplifier circuit configured to operate at an operating point determined by the bias current.

A protection circuit for use in an RF active circuit includes a signal strength detecting circuit, a current detecting circuit, a logic circuit, and a switching unit. The signal strength detecting circuit is coupled to the signal input end or the signal output end of the RF active circuit and configured to generate a first detecting signal according to the signal strength of the RF signal. The current detecting circuit is configured to detect the VSWR of the RF signal based on the driving current of the RF active circuit, thereby generating a corresponding second detecting signal. The logic circuit is configured to generate a switch control signal according to the first detecting signal and the second detecting signal. The switching unit is configured to lower the driving current of the RF active circuit according to the switch control signal.

A protection circuit for use in an RF active circuit includes a signal strength detecting circuit, a current detecting circuit, a logic circuit, and a switching unit. The signal strength detecting circuit is coupled to the signal input end or the signal output end of the RF active circuit and configured to generate a first detecting signal according to the signal strength of the RF signal. The current detecting circuit is configured to detect the VSWR of the RF signal based on the driving current of the RF active circuit, thereby generating a corresponding second detecting signal. The logic circuit is configured to generate a switch control signal according to the first detecting signal and the second detecting signal. The switching unit is configured to lower the driving current of the RF active circuit according to the switch control signal.

Certain aspects of the present disclosure provide methods and apparatus for generating an envelope tracking power supply voltage. For example, certain aspects of the present disclosure provide an envelope tracking power supply having a linear amplifier having an output coupled to a power supply node of an amplifier, wherein a power supply node of the linear amplifier is coupled to a first voltage supply node. The envelope tracking power supply may also include a switch mode power supply having an output coupled to the power supply node of the amplifier. Certain aspects also include a circuit having a first switch coupled to the first voltage supply node and a second switch coupled to a second voltage supply node, wherein a power supply node of the switch mode power supply is coupled to the first switch and the second switch.

Certain aspects of the present disclosure provide methods and apparatus for generating an envelope tracking power supply voltage. For example, certain aspects of the present disclosure provide an envelope tracking power supply having a linear amplifier having an output coupled to a power supply node of an amplifier, wherein a power supply node of the linear amplifier is coupled to a first voltage supply node. The envelope tracking power supply may also include a switch mode power supply having an output coupled to the power supply node of the amplifier. Certain aspects also include a circuit having a first switch coupled to the first voltage supply node and a second switch coupled to a second voltage supply node, wherein a power supply node of the switch mode power supply is coupled to the first switch and the second switch.

A power amplifier module includes an output-stage amplifier, a driver-stage amplifier, an input switch, an output switch, an input matching circuit, an inter-stage matching circuit, an output matching circuit, and a control circuit. The input switch selectively connects one of a plurality of input signal paths to an input terminal of the driver-stage amplifier. The output switch selectively connects one of a plurality of output signal paths to an output terminal of the output-stage amplifier. The control circuit controls operations of the driver-stage amplifier and the output-stage amplifier. The input switch, the output switch, and the control circuit are integrated into an IC chip. The control circuit is disposed between the input switch and the output switch.

A power amplifier module includes an output-stage amplifier, a driver-stage amplifier, an input switch, an output switch, an input matching circuit, an inter-stage matching circuit, an output matching circuit, and a control circuit. The input switch selectively connects one of a plurality of input signal paths to an input terminal of the driver-stage amplifier. The output switch selectively connects one of a plurality of output signal paths to an output terminal of the output-stage amplifier. The control circuit controls operations of the driver-stage amplifier and the output-stage amplifier. The input switch, the output switch, and the control circuit are integrated into an IC chip. The control circuit is disposed between the input switch and the output switch.

Methods of managing heat generated by amplifiers are disclosed. A metal pillar, a plurality of resistors, and a transistor array are formed over a silicon substrate. The plurality of resistors provide emitter-ballasting for the amplifier. A footprint defined by a periphery of the metal pillar is adjacent to a footprint defined by a periphery of the transistor array and overlaps a footprint defined by a periphery of the plurality of resistors so that heat generated during operation of the amplifier is transferred through the silicon substrate to the metal pillar.

Methods of managing heat generated by amplifiers are disclosed. A metal pillar, a plurality of resistors, and a transistor array are formed over a silicon substrate. The plurality of resistors provide emitter-ballasting for the amplifier. A footprint defined by a periphery of the metal pillar is adjacent to a footprint defined by a periphery of the transistor array and overlaps a footprint defined by a periphery of the plurality of resistors so that heat generated during operation of the amplifier is transferred through the silicon substrate to the metal pillar.

Systems, methods, and apparatus for an improved body tie construction are described. The improved body tie construction is configured to have a lower resistance body tie exists when the transistor is off (Vg approximately 0 volts). When the transistor is on (Vg>Vt), the resistance to the body tie is much higher, reducing the loss of performance associated with presence of body tie. Space efficient Body tie constructions adapted for cascode configurations are also described.