A power amplifier circuit includes a first transistor disposed on a semiconductor substrate; a second transistor that supplies a bias current based on a first current which is a part of a control current to the first transistor; a current output element in which a current flowing therethrough increases in accordance with a rise in temperature; and a wiring portion including a plurality of metal layers that are electrically connected to an emitter of the first transistor and that are stacked one on top of another so as to oppose the semiconductor substrate. At least one metal layer among the plurality of metal layers extends so as to overlap an area extending from at least a part of a first disposition area in which the first transistor is disposed to a second disposition area in which the current output element is disposed in plan view of the semiconductor substrate.

The disclosure provides an improved transimpedance amplifier (TIA) that can operate at a higher bandwidth and lower noise compared to conventional TIAs. The TIA employs a data path with both feedback impedance and feedback capacitance for improved performance. The feedback impedance includes at least two resistors in series and at least one shunt capacitor, coupled between the at least two resistors, that helps to extend the circuit bandwidth and improve SNR at the same time. The capacitance value of the shunt capacitor can be selected based on both the bandwidth and noise. In one example, the TIA includes: (1) a biasing path, and (2) a data path, coupled to the biasing path, including multiple inverter stages and at least one feedback capacitance coupled across an even number of the multiple inverter stages. An optical receiver and a circuit having the TIA are also disclosed.

An apparatus includes a photodetector configured to generate an electrical current based on received illumination. The apparatus also includes a capacitor transimpedance amplifier (CTIA) unit cell having (i) an amplifier configured to receive the electrical current and a reference voltage, (ii) a feedback capacitor coupled in parallel across the amplifier, and (iii) a reset switch coupled in parallel across the feedback capacitor. The apparatus further includes an event detector configured to sense a high-energy event affecting the photodetector. In addition, the apparatus includes a switchable clamp coupled across inputs of the amplifier, where the event detector is configured to close the switchable clamp in response to sensing the high-energy event.

An apparatus includes a photodetector configured to generate an electrical current based on received illumination. The apparatus also includes a capacitor transimpedance amplifier (CTIA) unit cell having (i) an amplifier configured to receive the electrical current and a reference voltage, (ii) a feedback capacitor coupled in parallel across the amplifier, and (iii) a reset switch coupled in parallel across the feedback capacitor. The apparatus further includes an event detector configured to sense a high-energy event affecting the photodetector. In addition, the apparatus includes a switchable clamp coupled across inputs of the amplifier, where the event detector is configured to close the switchable clamp in response to sensing the high-energy event.

An operational amplifier 1 comprises transistors Q1 and Q2 forming an input stage, and input resistors R1 and R2 which form a filter together with parasitic capacitors C1 and C2 accompanying the transistors Q1 and Q2. Resistance values R of the resistors R1 and R2 may be set to R=1/(2π.Math.fc.Math.C), where C is the capacitance value of each of the parasitic capacitors C1 and C2, and fc is the target cutoff frequency of the filter. The operational amplifier 1 may also include a power supply resistor R0 which forms a filter together with a parasitic capacitor C0 accompanying a power supply line.

An amplifier includes a transistor, an input circuit coupled between an amplifier input and a transistor input terminal, and an output circuit coupled between a transistor output and a transistor output terminal. The input circuit includes an input-side harmonic termination circuit with a first inductor and a first capacitance in series between the transistor input terminal and ground. The output circuit includes a second inductor, an output-side harmonic termination circuit, and a shunt-L circuit. The second inductor is coupled between the transistor output terminal and the amplifier output. The output-side harmonic termination circuit includes a third inductor and a second capacitance in series between the amplifier output and ground. The shunt-L circuit includes a fourth inductor and a third capacitance connected in series between the amplifier output and ground. The input-side and output-side harmonic termination circuits resonate at a harmonic frequency of a fundamental frequency of operation of the amplifier.

A system includes a transimpedance amplifier, disposed on a chip, having a front-end section and a back-end section; an on-chip linear regulator, on the chip, arranged to power the front-end section; and an off-chip switching regulator, off the chip, arranged to power the back-end section. The arrangement provides low noise power supply for the front-end section, while providing a more power efficient switching regulator to power the back-end section. The output voltage of the on-chip linear regulator and the output voltage of the off-chip switching regulator are controlled to be the same.

An electronic circuit for a micro-electro-mechanical systems gyroscope is disclosed. The electronic circuit includes a current buffer, a transimpedance amplifier coupled with the current buffer, and a plurality of transistors. An inverting input terminal of the current buffer and a non-inverting input terminal of the current buffer are connected with a plurality of first resistors. The inverting input terminal of the current buffer is connected with a source of one of the plurality of transistors, and the non-inverting input terminal of the current buffer is connected with a source of another one of the plurality of transistors. The plurality of first resistors are connected to a ground. The current buffer is configured to isolate a load in the micro-electro-mechanical systems gyroscope from the transimpedance amplifier.

Disclosed are embodiments of a transceiver front-end configured for a reduced noise figure (NF). Each of the embodiments includes an antenna, a transmitter branch and a receiver branch all connected to an input/output pad. The transmitter branch is coupled to the input/output pad (and thereby the antenna) by an impedance transformer. Only the receiver branch is selectively electrically connected to the input/output pad (and thereby the antenna) by a switch. A common matching network between the input/output pad and the switch provides both impedance matching and electrostatic discharge protection for the switch and the low noise amplifier, thereby reducing NF. Specific embodiments are disclosed for integration into specific technologies (e.g., fully depleted silicon-on-insulator (FDSOI) technology and fin-type field effect transistor (finFET) technology).

A system may include a first input for receiving a first signal for driving an amplifier that drives a load, a second input for receiving a second signal driven by the amplifier, and an instability detector for detecting instability of a feedback loop for controlling the first signal based on comparison of the first signal and the second signal.