A transmitter device which transmits a first transmit signal and a second transmit signal having different wireless communication standards. The transmitter device includes a power amplifier that amplifies the first transmit signal in a first transmission mode. A first impedance circuit provides the amplified first transmit signal to a radio frequency output port. A second impedance circuit is connected to the first impedance circuit and provides an additional impedance to the first impedance circuit in the first transmission mode. A first switch provides the second transmit signal to the first impedance circuit in a second transmission mode. A second switch connects the second impedance circuit and a ground in the first transmission mode, and floats the second impedance circuit in the second transmission mode.

An amplifier circuit has an amplification path including an amplifier and a bypass path configured to bypass at least the amplifier. The bypass path includes a switch coupled in series on the bypass path and another switch coupled in series between the bypass path and ground. The amplification path further includes an inductor coupled on an output side with respect to the amplifier and a switch coupled between the inductor and ground on a path between the inductor and the amplifier.

An amplifying apparatus includes a variable gain amplifying circuit configured to operate in a gain mode selected from a plurality of gain modes in response to a first control signal during operation in an amplification mode, a variable attenuation circuit configured to have an attenuation value that is adjusted in response to a second control signal, and a phase compensation value which compensates for a phase distortion in the selected gain mode, and a control circuit configured to control the selecting of the gain mode, the adjusting of the attenuation value and the phase compensation value, based on the first and second control signals.

The present disclosure describes exemplary line drivers for use in an exemplary wireline transmission device. In some situations, the exemplary line drivers are electrically connected to a wireline communication channel to transmit information. The exemplary line drivers prevent charge sharing with the wireline communication channel. The exemplary line drivers disclosed herein charge various circuit nodes to various logical values, such as a logical zero or a logical one, to prevent charge sharing with the wireline communication channel.

A transmitter device which transmits a first transmit signal and a second transmit signal having different wireless communication standards. The transmitter device includes a power amplifier that amplifies the first transmit signal in a first transmission mode. A first impedance circuit provides the amplified first transmit signal to a radio frequency output port. A second impedance circuit is connected to the first impedance circuit and provides an additional impedance to the first impedance circuit in the first transmission mode. A first switch provides the second transmit signal to the first impedance circuit in a second transmission mode. A second switch connects the second impedance circuit and a ground in the first transmission mode, and floats the second impedance circuit in the second transmission mode.

An LNA circuit includes: paths provided between an input and an output terminals, an LNA provided in at least one path, and a selector selecting one path. The LNA includes: a MOS transistor coupled between a first and a second power supplies, a first inductor coupled to a source of the MOS transistor, a capacitor formed between a gate and the source of the MOS transistor, a second inductor coupled between the gate of the MOS transistor and the input terminal, and a changeover switch coupled parallelly with at least one of the capacitor, and the first and the second inductors. The selector switches between a first state that one path is selected and the changeover switch is on, and a second state that another path is selected and the changeover switch is off. Alternatively, the one path and the another path are respectively provided without and with the LNA.

A high-frequency amplifier circuit has a source-grounded first transistor that amplifies a high-frequency input signal, a gate-grounded second transistor that further amplifies the amplified signal, a first inductor and a first reference voltage node, a second inductor connected between a first node and a second reference voltage node, a third transistor that is connected between the first node and a drain of the second transistor, is turned on at the time of selecting the first mode to transmit the amplified signal to the first node, and is turned off when selecting a second mode to disconnect the first node from the drain of the second transistor, a bypass path that bypasses the high-frequency input signal from an input node of the high-frequency input signal to the first node at the time of selecting the second mode, and a bypass switching circuit that is connected on the bypass path.

An amplification device including: a switch including an output that is suitable for being connected to a first or a second input; a first branch that is connected to the first input, which applies a first gain to generate a first amplified signal; a second branch that is connected to the second input, which applies a second gain to generate a second amplified signal; a controller for controlling the switching of the switch to apply the first or the second amplified signal to the output, depending on whether or not the value of a predetermined quantity of the first amplified signal falls within a predetermined range. The first gain and the second gain being non-zero real numbers of opposite sign.

A multi-stage amplifier with a high signal-to-noise ratio is introduced. Multiple amplification stages are cascaded between an input terminal and an output terminal of the amplifier. A controller switches the output stage among the multiple amplification stages from a normal mode to an attenuation mode in response to the amplifier input being lower than the threshold. In the attenuation mode, the output stage provides an attenuation resistor coupled in series with the load resistor of the amplifier. Noise is successfully attenuated by the attenuation-mode output stage.

An LNA having a plurality of paths, each of which can be controlled independently to achieve a gain mode. Each path includes at least an input FET and an output FET coupled in series. A gate of the output FET is controlled to set the gain of the LNA. Signals to be amplified are applied to the gate of the input FET. Additional stacked FETs are provided in series between the input FET and the output FET.