A transimpedance amplifier may include a voltage-controlled operational amplifier having a non-inverting input connected to ground, an inverting input receiving a current signal to be amplified, an output coupled to the inverting input via a coupling resistor, and a power-down input (PWDN input) activated upon receipt of at least one power-down signal (PWDN) such that at least one internal current source is thereupon deactivated.

A receiver circuit is configured to receive input signals having a first reference voltage level. The first reference voltage level is a first logical high voltage level. The receiver circuit comprises an input stage comprising a resistive voltage divider. The resistive voltage divider is configured to convert the input signals having the first reference voltage level to input signals having a second reference voltage level. The second reference voltage level is a second logical high voltage level. The receiver circuit comprises a preamplifier configured to receive and amplify the input signals having the second reference voltage level.

A bidirectional data link includes a forward channel transmitter circuit and a forward channel receiver circuit. The forward channel transmitter circuit includes a forward channel driver circuit, and a back channel receiver circuit. The back channel receiver circuit is coupled to the forward channel driver circuit. The back channel receiver circuit includes a summation circuit and an active filter circuit. The summation circuit is coupled to the forward channel driver circuit. The active filter circuit is coupled to the summation circuit. The forward channel receiver circuit includes a forward channel receiver, and a back channel driver circuit. The back channel driver circuit is coupled to the forward channel receiver.

A half-power buffer amplifier is disclosed. The amplifier includes an amplification unit configured to differentially amplify differential input signals, the amplification unit including nodes configured to output differentially amplified first to fourth output signals, a first output buffer unit including first and second transistors, and an output node to which the first and second transistors are connected, a second output buffer unit including third and fourth transistors, wherein the third and fourth transistors are connected to the output node, a first control switch between the first output node and the second transistor and controlled by a polarity control signal, and a second control switch between the second output node and the third transistor and controlled by a complement of the polarity control signal.

A semiconductor memory device includes a sense amplifier, a voltage supply circuit and a voltage supply control circuit. The sense amplifier may be activated by receiving driving voltages from first to third voltage supply lines to detect and amplify voltage levels of a data line and a data bar line. The voltage supply circuit may apply the driving voltages to the first to third voltage supply lines in response to first to third voltage supply signals and a bias control signal. The voltage supply control circuit may generate the first to third voltage supply signals and the bias control signal in response to an active signal.

System and method for error amplification and processing. For example, the system includes: a signal processing unit configured to receive a reference signal and a feedback signal and generate a digital pulse signal, a frequency of the digital pulse signal being associated with a difference between the reference signal and the feedback signal; a counter configured to receive the digital pulse signal and generate a counter output signal based on at least information associated with the digital pulse signal; and a digital-to-analog converter configured to receive the counter output signal and generate an output signal based on at least information associated with the counter output signal.

Embodiments relate to an amplifier circuit. The amplifier circuit includes multiple transistors. Each transistor is configured to receive an input signal and output an amplified signal. The amplifier circuit additionally includes a set of input chopper circuits and a set of output chopper circuits. Each output chopper circuit corresponds to one input chopper of the set of input choppers. Each input chopper circuit and its corresponding output chopper are controlled by one or more control signals from a set of control signals. Each input chopper circuit is configured to selectively connect each transistor of a transistor pair to a first input terminal or a second input terminal based on a value of the one or more control signals. Moreover, each output chopper circuit is configured to selectively connect each transistor of the transistor pair to a first output terminal or a second output terminal based on the value of the one or more control signals.

A differential amplifier circuit includes a first and second amplifiers that output a differential signal in a radio-frequency band, a first inductor having a first end connected to an output end of the first amplifier, a second inductor having a first end connected to an output end of the second amplifier, a choke inductor connected to second ends of the first and second inductors, a first and second capacitors, and a switch that connects the second capacitor in parallel to the first capacitor or terminates a parallel connection of the first and second capacitors. A resonant circuit formed by connecting the first or second inductor in series with the first capacitor has a different resonant frequency from a resonant circuit formed by connecting the first or second inductor in series with the parallel-connected first and second capacitors. These resonant frequencies correspond to second harmonic frequencies of the differential signal.

A voltage-to-current converter that reduces third harmonic distortion. An amplifier includes an input stage. The input stage includes a first voltage-to-current conversion stage and a second voltage-to-current conversion stage. The first voltage-to-current conversion stage is configured to provide an input to output gain with compressive nonlinearity. The second voltage-to-current stage is cascaded with the first voltage-to-current conversion stage. An input of the second voltage-to-current stage is connected to an output of the first voltage-to-current conversion stage. The second voltage-to-current conversion stage is configured to provide an input to output gain with expansive nonlinearity.

An amplifier module includes an input terminal; a first preamplifier formed in or on a first substrate and configured to amplify a signal that is input to the input terminal; a first postamplifier and a second postamplifier that are formed in or on a second substrate and that are configured to receive an output of the first preamplifier and output a differential signal; an output balun configured to receive the differential signal that is output from the first postamplifier and the second postamplifier; and a variable capacitance element. The output balun includes a primary winding subjected to the differential signal and a secondary winding, and the variable capacitance element is connected in parallel with the primary winding of the output balun.