Certain aspects of the present disclosure generally relate to a multi-output amplifier implemented using a capacitive attenuator. For example, the multi-output amplifier generally includes a first capacitive attenuator coupled to an input node of the multi-output amplifier. In certain aspects, the multi-output amplifier also includes a first amplification stage having an input coupled to a tap node of the first capacitive attenuator and an output coupled to a first output node of the multi-output amplifier, and a second amplification stage having an output coupled to a second output node of the multi-output amplifier. For certain aspects, the multi-output amplifier includes a second capacitive attenuator coupled to the input node of the multi-output amplifier, and the second amplification stage may have an input coupled to a tap node of the second capacitive attenuator.

In accordance with an embodiment, a system for amplifying a signal provided by a capacitive signal source includes an impedance converter having an input node configured to be coupled to a first terminal of the capacitive signal source, and an adjustable capacitive network having a first node configured to be coupled to a second terminal of the capacitive signal source and a second node coupled to an output node of the impedance converter.

One aspect of the present disclosure relates to a method for operating an amplifier, the amplifier including a variable resistor coupled between a source of a first input transistor and a source of a second input transistors, and a variable capacitor coupled between the source of the first input transistor and the source of the second input transistor. The method includes adjusting a resistance of the variable resistor to adjust a low-frequency gain of the amplifier, and adjusting a capacitance of the variable capacitor in an opposite direction as the adjustment to the resistance of the variable resistor.

Certain aspects of the present disclosure generally relate to a multi-output amplifier implemented using a capacitive attenuator. For example, the multi-output amplifier generally includes a first capacitive attenuator coupled to an input node of the multi-output amplifier. In certain aspects, the multi-output amplifier also includes a first amplification stage having an input coupled to a tap node of the first capacitive attenuator and an output coupled to a first output node of the multi-output amplifier, and a second amplification stage having an output coupled to a second output node of the multi-output amplifier. For certain aspects, the multi-output amplifier includes a second capacitive attenuator coupled to the input node of the multi-output amplifier, and the second amplification stage may have an input coupled to a tap node of the second capacitive attenuator.

Provided is an amplification circuit that amplifies an input signal and outputs an amplified signal. The amplification circuit includes: an amplification element that outputs the amplified signal from an output terminal thereof; an inductor having one end to which a power supply voltage is supplied and another end that is connected to the output terminal of the amplification element; a variable resistor that is connected in parallel with the inductor; and a resistance value adjusting circuit that adjusts a resistance value of the variable resistor in accordance with the temperature.

A variable gain amplifier capable of stabilizing an average output potential of a differential output signal, improving power efficiency over a wide range of an amplitude of the differential input signal, and suppressing deterioration of a distortion rate is provided. The variable gain amplifier includes an amplifying circuit configured to amplify a differential input signal with a gain according to a gain control signal, and a current control circuit. The amplifying circuit has a first current source supplying a source current. The current control circuit adjusts a magnitude of the source current of the first current source according to a magnitude of the gain control signal.

An equalizer, in at least some embodiments, comprises an amplifier configured to produce an amplified voltage signal that is a function of an ambient temperature affecting the equalizer. The equalizer also includes a linear equalizer stage coupled to the amplifier and comprising a transistor having a resistance controlled by the amplified voltage signal. The linear equalizer stage is configured to produce a voltage output signal having a gain that is dependent on the transistor resistance and on a frequency of the amplified voltage signal.

The present invention is directed to electrical circuits. More specifically, embodiments of the present invention provide a variable gain amplifier (VGA) device that includes a low-gain tuning section and a high-gain tuning section. The low-gain tuning section includes both resistor and transistor elements. The high-gain tuning section includes a transistor element and is activated when an output gain is greater than a predetermined threshold level. There are other embodiments as well.

A transistor cell can be modeled as a transistor with a collector, a base, and an emitter operating with a current at the collector to produce a minimum transconductance in the transistor cell that increases a current gain and improves at least one operating characteristic of the transistor cell. The operating characteristics include bandwidth, gain, and output power.

The disclosure provides an RF receiver. The RF receiver includes an input driver. The input driver receives a coarse signal, and generates an input signal. A digital step attenuator (DSA) is coupled to the input driver and receives the input signal. An analog to digital converter (ADC) is coupled to the DSA. The DSA includes a serial capacitor coupled to the input driver. The DSA also includes a sampling capacitor coupled to the ADC.