In one embodiment, an electronic system includes a printed circuit board, one or more packaged semiconductor devices, and a vapor chamber having a top and a bottom and enclosing a sealed cavity that is partially filled with a coolant. The vapor chamber comprises a thermo-conductive and electro-conductive material. The top of the vapor chamber has one or more depressions formed therein, each depression receiving and thermo-conductively connected to at least part of a bottom of a corresponding packaged semiconductor device, which is mounted through a corresponding aperture in the PCB. A heat sink may be thermo-conductively attached to the bottom of the vapor chamber.

An apparatus that generates and limits a bias current of a power amplifier is provided. The apparatus includes a bias current circuit that generates a bias current to bias the power amplifier, and critically limit an increase in bias current, and a band gap reference circuit that provides a reference voltage or a reference current to the bias current circuit. The bias current circuit is configured to critically limit the increase in bias current, as a first bias transistor that generates the bias current is converted from a triode region to a saturation region, based on the reference voltage or the reference current.

A method for facilitating the impedance matching of radiofrequency circuits, notably transmission circuits using a power amplifier connected to a load which may include an antenna. A signal is produced for measuring the temperature resulting from the operation of the output amplifier stage, by a temperature sensor positioned in the immediate vicinity of this stage, the measuring signal is used to control a circuit for controlling the variable impedances of a matching network positioned between the amplifier and the load, and values which seek to minimize the sensed temperature are applied to these variable impedances values. An abnormal heating of the amplifier is an indication of an impedance mismatch that must be corrected to restore a minimum temperature.

A power amplifier circuit includes an amplifier transistor that amplifies a radio-frequency signal and outputs the radio-frequency signal, and a bias circuit that supplies a bias current to a base of the amplifier transistor. The bias circuit includes a bias current supply transistor, and an electrostatic capacity circuit whose electrostatic capacity varies in accordance with a temperature of the amplifier transistor and that is charged in a non-supply period during which the bias current is not supplied and discharges to a supply path for the bias current in a supply period during which the bias current is supplied. The supply period during which the bias current is supplied includes an amplification period during which the radio-frequency signal is amplified by the amplifier transistor. The bias current starts to be supplied before the amplifier transistor starts amplification.

A semiconductor integrated circuit is capable of electrically connecting to a capacitance variable capacitor whose electrostatic capacitance changes corresponding to an environmental change between a first and a second capacitances and determines whether the electrostatic capacitance of the capacitance variable capacitor has changed to exceed a reference capacitance value. The semiconductor integrated circuit includes a reference capacitor having a fixed electrostatic capacitance between the first capacitance and the second capacitance as the reference capacitance value; and an amplifier circuit, charging the capacitance variable capacitor via a first node and charging the reference capacitor via a second node corresponding to a clock signal, amplifying a potential difference between a potential of the first node and a potential of the second node, and outputting a binary determination signal indicating whether the electrostatic capacitance of the capacitance variable capacitor has changed to exceed the reference capacitance value based on the amplified potential difference.

A power amplifier circuit includes a power amplifier that amplifies the power of a high frequency signal, a power amplifier temperature detector circuit that includes a temperature detection element, the temperature detection element being thermally coupled with the power amplifier, a bias control signal generator circuit that generates a bias control signal for the power amplifier based on a temperature detection signal outputted from the power amplifier temperature detector circuit, and a regulator circuit that stabilizes the temperature detection signal. The power amplifier, the power amplifier temperature detector circuit, and the regulator circuit are formed in a first integrated circuit, and the bias control signal generator circuit is formed in a second integrated circuit. The substrate material (for example, GaAs) of the first integrated circuit has a higher cutoff frequency than the substrate material (for example, SOI) of the second integrated circuit.

A wide bandgap voltage reference circuit generates a temperature stable negative bias reference voltage for use in wide bandgap circuits. The reference circuit uses field effect transistor (FET) based source feedback. It can also be used as source feedback in high power high bandgap device applications, where constant current is required over process and thermal variations.

Split cascade circuits include multiple cascade paths coupled between voltage supply rails. Each cascade path includes a pair of controllable switches. A feedback path is provided for at least one of the cascade circuit paths. An active load circuit may also have a split cascade structure. Multiple-stage circuits, for implementation in Trans-Impedance Amplifiers (TIAs) or analog Receive Front-End modules (RXFEs), for example, include multiple stages of split cascade circuits.

A temperature correction circuit and method for maintaining a transistor of a power amplifier in a linear operating region of the transistor. The temperature correction circuit includes a first current source circuit operable to provide a first correction current proportional to an absolute temperature of a semiconductor die including the transistor. The temperature correction circuit also includes a second current source circuit operable to provide a second correction current proportional to a change in temperature of a part of the semiconductor die in which the transistor is located during operation of the transistor. The temperature correction circuit further includes a third current source circuit operable to provide a gain selection current. The temperature correction circuit also includes circuitry for producing a reference current from the first and second correction currents and the gain current. The temperature correction circuit further includes an output for providing the reference current to the transistor.

Devices and methods related to embedded sensors for dynamic error vector magnitude corrections. In some embodiments, a power amplifier (PA) can include a PA die and an amplification stage implemented on the PA die. The amplification stage can include an array of amplification transistors, with the array being configured to receive and amplify a radio-frequency (RF) signal. The PA can further include a sensor implemented on the PA die. The sensor can be positioned relative to the array of amplification transistors to allow sensing of an operating condition representative of at least some of the amplification transistors. The sensor can be substantially isolated from the RF signal.