Provided are an amplifier circuit capable of reducing DC offset voltage without an increase in chip area and degradation in frequency characteristics, and a multipath nested miller amplifier circuit. The amplifier circuit includes a chopper switching circuit, a sampling circuit configured to sample an output signal from the chopper switching circuit, and a holding circuit configured to hold a signal output from the sampling circuit.

A DC offset cancellation circuit and a DC offset cancellation method are disclosed. The DC offset cancellation circuit comprises a high-speed amplifier, a voltage comparator, a microprocessor, and a digital-to-analog converter. The high-speed amplifier comprises an input stage with a DC offset cancellation function, an amplification stage, and an output buffer stage. The voltage comparator is connected to the output buffer stage. The microprocessor is connected to the voltage comparator. The digital-to-analog converter is connected to the microprocessor. The digital-to-analog converter is connected to the input stage.

An inductor isolation apparatus and method to reduce interaction between inductors on an integrated circuit.

Provided is a semiconductor device with a reduced variation in temperature among a plurality of unit transistors. A semiconductor device includes: a semiconductor substrate; and a transistor group including at least one column in which a plurality of unit transistors are aligned and arranged along a first axis on the semiconductor substrate. A first column of the at least one column includes: a first group of transistors including two of the unit transistors that are adjacent to each other with a first distance therebetween, and a second group of transistors including two of the unit transistors that are adjacent to each other with a second distance therebetween, the first group of transistors is disposed at a position closer to a center of the first column along the first axis than the second group of transistors, and the first distance is larger than the second distance.

According to the present invention, an integrated circuit includes a first amplifier stage, a second amplifier stage, a first signal line connecting an output of the first amplifier stage and an input of the second amplifier stage to each other, a first plane for ground connected to the first amplifier stage, a second plane for ground connected to the second amplifier stage and at least one at least one line for ground connecting the first plane and the second plane to each other, wherein the at least one line has a center line having a length of 10 μm to 1 mm, a width of the at least one line is ⅓ or less of a width of the first plane, and a pattern ratio is 1 or more.

A system to program parameters of one or more stages of a transimpedance amplifier (TIA) in an optical sub-assembly (e.g. TO-can package) is disclosed. With this invention, users have the option/flexibility to discretely program any of the stages of the TIA after production of the sub-assembly, i.e. they can still change the TIA settings once the TIA has been installed in a system and the system is in use.

Radio frequency (RF) amplification devices are disclosed along with methods of providing power to an RF signal. In one embodiment, an RF amplification device includes an RF amplification circuit and a voltage regulation circuit. The RF amplification circuit includes a plurality of RF amplifier stages coupled in cascade. The voltage regulation circuit is coupled to provide a regulated voltage to a driver RF amplifier stage. The voltage regulation circuit is configured to generate the regulated voltage so that the maximum output power of the RF amplification circuit is provided approximately at a first power level while the supply voltage is above a threshold voltage level. The first power level should be within the physical capabilities of the RF amplification circuit, and thus, the RF amplification circuit is prevented from being damaged once the supply voltage is above the threshold voltage level.

An optical receiver includes an APD that converts an input optical signal into a current signal, a TIA that converts the current signal output from the APD into a voltage signal, an LIA that shapes a waveform of the voltage signal output from the TIA, an AOC having a time constant switching function, the AOC automatically compensating for an offset voltage between differential outputs from the TIA, and a convergence-state detection circuit that outputs, after detecting convergence completion of the automatic compensation in the AOC, to the AOC, a time constant switching control signal for switching a time constant from a high-speed time constant to a low-speed time constant.

A semiconductor device includes: a semiconductor substrate whose contour is a pentagon; a front-stage amplifier formed relatively near a vertex of the pentagon of the semiconductor substrate; and a rear-stage amplifier formed relatively near a side opposed to the vertex of the semiconductor substrate and amplifying an output from the front-stage amplifier.

A compound semiconductor device includes a heterojunction bipolar transistor and a bump. The heterojunction bipolar transistor includes a plurality of unit transistors. The bump is electrically connected to emitters of the plurality of unit transistors. The plurality of unit transistors are arranged in a first direction. The bump is disposed above the emitters of the plurality of unit transistors while extending in the first direction. The emitter of at least one of the plurality of unit transistors is displaced from a center line of the bump in the first direction toward a first side of a second direction which is perpendicular to the first direction. The emitter of at least another one of the plurality of unit transistors is displaced from the center line of the bump in the first direction toward a second side of the second direction.