Thermal temperature sensors for power amplifiers are provided herein. In certain implementations, a semiconductor die includes a compound semiconductor substrate, and a power amplifier including a plurality of field-effect transistors (FETs) configured to amplify a radio frequency (RF) signal. The plurality of FETs are arranged on the compound semiconductor substrate as a transistor array. The semiconductor die further includes a semiconductor resistor configured to generate a signal indicative of a temperature of the transistor array. The semiconductor resistor is located adjacent to one end of the transistor array.

Thermal temperature sensors for power amplifiers are provided herein. In certain implementations, a semiconductor die includes a compound semiconductor substrate, and a power amplifier including a plurality of field-effect transistors (FETs) configured to amplify a radio frequency (RF) signal. The plurality of FETs are arranged on the compound semiconductor substrate as a transistor array. The semiconductor die further includes a semiconductor resistor configured to generate a signal indicative of a temperature of the transistor array. The semiconductor resistor is located adjacent to one end of the transistor array.

An operational amplifier includes a voltage terminal; a common terminal; a first amplification stage for receiving a differential signal pair to generate a single-end amplification signal; a first buffer for generating a first voltage according to the single-end amplification signal; a first diode for reducing the first voltage to generate a second voltage; a second amplification stage for amplifying the second voltage to generate a third voltage; a voltage stabilizing circuit for stabilizing the third voltage; a second diode coupled between the second amplification stage and the common terminal; a second buffer for generating an output voltage according to the third voltage; and a current mirror coupled to the common terminal, the first amplification stage, the first diode and the second amplification stage.

Thermal temperature sensors for power amplifiers are provided herein. In certain implementations, a semiconductor die includes a compound semiconductor substrate, and a power amplifier including a plurality of field-effect transistors (FETs) configured to amplify a radio frequency (RF) signal. The plurality of FETs are arranged on the compound semiconductor substrate as a transistor array. The semiconductor die further includes a semiconductor resistor configured to generate a signal indicative of a temperature of the transistor array. The semiconductor resistor is located adjacent to one end of the transistor array.

Circuits for protecting devices, such as gallium nitride (GaN) devices, and operating methods thereof are described. Such circuits may include a temperature sensor configured to sense the temperature of at least a portion of a device, and a phase shifter configured to shift the phase of the signal output by the device, when the sensed temperature is outside a safe temperature range, e.g., above a predefined temperature threshold. The phase may be shifted discretely or continuously. These circuits safeguard devices from damaging operating conditions to prolong the operating life of the protected devices.

A power amplifier system having a power amplifier with a signal input and a signal output and bias circuitry is disclosed. The bias circuitry includes a bandgap reference circuit coupled between a reference node and a fixed voltage node. A bias generator has a bias input coupled to the reference node and a bias output coupled to the signal input. Also included is a first digital-to-analog converter having a first converter output coupled to the reference node, a first voltage input, and a first digital input, wherein the first digital-to-analog converter is configured to adjust a reference voltage at the reference node in response to a first digital setting received at the first digital input. The first digital setting correlates with an indication of temperature of the power amplifier.

Methods and devices are disclosed for compensating for device property variations across a wafer. The method comprises determining an output of a first device based on an input and determining an output of a second device based on the input. The second device is located at a different position with respect to a center of the wafer than a position of the first device with respect to the center of the wafer. The method further comprises determining a difference between the output of the first device and the output of the second device, the difference arising at least in part from the difference in position of the first and second devices. The method further comprises altering the first device such that the output of the first device based on the input substantially matches the output of the second device based on the input.

Thermal temperature sensors for power amplifiers are provided herein. In certain implementations, a semiconductor die includes a compound semiconductor substrate, and a power amplifier including a plurality of field-effect transistors (FETs) configured to amplify a radio frequency (RF) signal. The plurality of FETs are arranged on the compound semiconductor substrate as a transistor array. The semiconductor die further includes a semiconductor resistor configured to generate a signal indicative of a temperature of the transistor array. The semiconductor resistor is located adjacent to one end of the transistor array.

An operational amplifier includes a voltage terminal; a common terminal; a first amplification stage for receiving a differential signal pair to generate a single-end amplification signal; a first buffer for generating a first voltage according to the single-end amplification signal; a first diode for reducing the first voltage to generate a second voltage; a second amplification stage for amplifying the second voltage to generate a third voltage; a voltage stabilizing circuit for stabilizing the third voltage; a second diode coupled between the second amplification stage and the common terminal; a second buffer for generating an output voltage according to the third voltage; and a current mirror coupled to the common terminal, the first amplification stage, the first diode and the second amplification stage.

A power amplifier system having a power amplifier with a signal input and a signal output and bias circuitry is disclosed. The bias circuitry includes a bandgap reference circuit coupled between a reference node and a fixed voltage node. A bias generator has a bias input coupled to the reference node and a bias output coupled to the signal input. Also included is a first digital-to-analog converter having a first converter output coupled to the reference node, a first voltage input, and a first digital input, wherein the first digital-to-analog converter is configured to adjust a reference voltage at the reference node in response to a first digital setting received at the first digital input. The first digital setting correlates with an indication of temperature of the power amplifier.