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.

An apparatus includes a differential current-to-voltage conversion circuit that includes an input sampling stage circuit, a differential integration and DC signal cancellation stage circuit, and an amplification and accumulator stage circuit. An input common mode voltage of the differential current-to-voltage circuit is independent of an output common mode voltage of the differential current-to-voltage circuit.

A reset signal is generated by a TIA circuit alone. In an embodiment, a transimpedance amplifier configured to convert a current signal into a voltage signal includes a transimpedance stage, a gain control circuit configured to compare an output of the transimpedance stage with a reference voltage and output a gain control voltage, and a reset signal output circuit configured to output a reset signal having a predetermined pulse width at a timing of at least one of a rise or a fall of the gain control voltage.

A variable resistance element is connected between a first input terminal of a first amplifier and a second input terminal of a second amplifier, and has a resistance value between the first input terminal and the second input terminal that is varied according to an amplitude value of a first voltage signal or an amplitude value or a differential voltage signal. A variable current source is connected between the first input terminal and a ground, and controls a current value of a current flowing to the ground from the first input terminal according to a value of an offset of the differential voltage signal. A bias voltage having the same value as that of a bias voltage that is applied to the first input terminal is applied to the second input terminal.

An amplifier has a first amplifying circuit configured to receive a voltage input and to output an amplified current, a second amplifying circuit configured to receive the amplified current and to output an amplified voltage, the second amplifying circuit comprising a pair of feedback resistive elements, each feedback resistive element being coupled to a gate and drain of a corresponding transistor in a pair of output transistors in the second amplifying circuit, and a feedback circuit configured to provide a negative feedback loop between an input and an output of the pair of output transistors, the feedback circuit including a first transconductance amplification circuit and a first equalizing circuit.

An example apparatus includes: a first voltage source, a first amplifier having a noninverting input adapted to be coupled to a photodiode anode and coupled to the first voltage source, an inverting input adapted to be coupled to a photodiode cathode, and an output, a first resistor coupled to the first amplifier inverting input and to the first amplifier output, a first capacitor coupled to the inverting input of the first amplifier and the first amplifier output, and a second voltage source different from the first voltage source. There is a second amplifier having a noninverting input, an inverting input and an output. The noninverting input is coupled to the output of the first amplifier, the inverting input is coupled to the second voltage source, and there is a second resistor coupled to the inverting input and the output of the second 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 photosensitive device includes a peripheral circuit semiconductor region, a photosensitive circuit semiconductor region including at least one group of at least two photosensitive elements configured to generate a photoelectric signal on a node called critical node. The device further includes an integrator circuit per group of photosensitive elements, each including: a differential circuit for each photosensitive element of the group, in the photosensitive circuit semiconductor region, an amplification circuit, in the peripheral circuit semiconductor region, and a feedback circuit for each photosensitive element of the group, comprising a capacitive element located in the photosensitive circuit semiconductor region coupled between the output node of the amplification circuit and the respective critical node.

Disclosed is an operational amplifier based on a metal-oxide TFT. The operational amplifier includes an auxiliary amplifier and a bootstrap gain-increasing amplifier. The auxiliary amplifier adopts a two-stage positive feedback structure, including a fifth transistor, a seventh transistor, an eleventh transistor, a first amplifying unit, and a second amplifying unit. A gate of the fifth transistor serves as an input end of the operational amplifier. The bootstrap gain-increasing amplifier includes two second circuits in mutual symmetry. Each of the second circuits includes a first transistor, a second transistor, and a current source unit with a bootstrap structure.

In optical receivers, extending the transimpedance amplifier's (TIA) dynamic range is a key to increasing the receiver's dynamic range, and therefore increase the channel capacity. Ideally, the TIA requires controllable gain, whereby the receiver can modify the characteristics of the TIA and/or the VGA to process high power incoming signals with a defined maximum distortion, and low power incoming signals with a defined maximum noise. A solution to the problem is to provide TIA's with reconfigurable feedback resistors, which are adjustable based on the level of power, e.g. current, generated by the photodetector, and variable load resistors, which are adjustable based on the change in impedance caused by the change in the feedback resistor.