Differential amplifier circuitry including: first and second main transistors of a given conductivity type: and first and second auxiliary transistors of an opposite conductivity type, where the first and second main transistors are connected along first and second main current paths passing between first and second main voltage reference nodes and first and second output nodes, respectively, with their source terminals connected to the first and second output nodes, respectively, and with their gate terminals controlled by component input signals of a differential input signal; and the first and second auxiliary transistors are connected along first and second auxiliary current paths passing between first and second auxiliary voltage reference nodes and the first and second output nodes, respectively, with their drain terminals connected to the first and second output nodes, respectively, and with their gate terminals controlled by the component input signals of the differential input signal.

A differential-follower control circuit has been provided, comprising: a follower; an output-voltage following module, which controls a voltage at a control terminal of the follower to vary with an output voltage; a substrate-voltage following module, which controls a substrate voltage of an output transistor of the follower to vary with an input voltage; an output terminal of the follower is connected to a first terminal of the output-voltage following module; a second terminal of the output-voltage following module is connected to the control terminal of the follower; a first terminal of the substrate-voltage following module is connected to an input terminal of the follower and a second terminal of the substrate-voltage following module is connected to a substrate of the output transistor; the invention effectively improves the overall linearity of the follower.

The disclosure provides a circuit. The circuit includes a gain stage block. The gain stage block is coupled to an input voltage through a first switch. A first capacitor is coupled between the first switch and a ground terminal. A second capacitor is coupled between the first switch and a second switch. A third switch is coupled between the second capacitor and a fixed terminal of the gain stage block.

An amplifier circuit having low parasitic pole effect includes a preamplifier, an output transistor and a buffer circuit. The buffer circuit generates a driving signal to control the output transistor according to a preamplification signal generated by the preamplifier. The buffer circuit includes: a buffer input transistor generating the driving signal, wherein an input impedance at its control end is less than that of the output transistor; a low output impedance circuit having an output impedance which is less than an inverting output impedance of the buffer input transistor; an amplification transistor generating an amplification signal at its inverting output; and an amplification stage circuit amplifying the amplification signal by an amplification ratio, so that an equivalent output impedance at a non-inverting output of the buffer input transistor is less than or equal to a product of the reciprocal of an intrinsic output impedance thereof and an amplification ratio.

A line receiver comprising a switched capacitor circuit and a buffer is described. The buffer may be configured to receive, through the switched capacitor circuit, an analog signal. In response, the buffer may provide an output signal to a load, such as an analog-to-digital converter. The switched capacitor circuit may be controlled by a control circuitry, and may charge at least one capacitive element to a desired reference voltage. The reference voltage may be selected so as to bias the buffer with a desired DC current, and consequently, to provide a desired degree if linearity. The line receiver may further comprise a bias circuit configured to generate the reference voltage needed to bias the buffer with the desired DC current.

A semiconductor device includes a low power fast differential transconductor, which provides an output current as a function of a difference between a reference potential input and a feedback potential input. The transconductance increases as an absolute value of the difference between the reference potential and the feedback potential increases. The transconductor includes a reference input stage to receive the reference potential and a reference load coupled in series with the reference input stage. The transconductor includes a feedback input stage to receive the feedback potential and a feedback load coupled in series with the feedback input stage. The transconductor further includes a current limiting component that is configured to control a total current through the reference input stage and the feedback input stage. The transconductor includes a negative feedback path from the reference load to the current limiting component, that compensates for changes in the total current due to differences between the reference potential and the feedback potential.

Bias arrangements for amplifiers are disclosed. An example bias arrangement for an amplifier includes a bias circuit, configured to produce a bias signal for the amplifier; a linearization circuit, configured to improve linearity of the amplifier by modifying the bias signal produced by the bias circuit to produce a modified bias signal to be provided to the amplifier; and a coupling circuit, configured to couple the bias circuit and the linearization circuit. Providing separate bias and linearization circuits coupled to one another by a coupling circuit allows separating a linearization operation from a biasing loop to overcome some drawbacks of prior art bias arrangements that utilize a single biasing loop.

An RF tuner is described for handling RF signals in a broad frequency range and a broad power range while maintaining high linearity and tolerating high power blockers. A continuous feedback loop comprising a substantially linear LNA and an RF RSSI can adjust the power of the RF signal on the RF side. A substantially linear, variable gain transconductor may convert and amplify the voltage of the RF signal to a current signal. The converted signal may be down converted and filtered to an IF or baseband signal. An IF or baseband RSSI may measure the power of the down converted and filtered signal. The measured power may be compared against a preferred value to adjust the amplification of the transconductor.

An example voltage regulator includes an output transistor that includes a source coupled to a first voltage supply node and a drain coupled to an output node. The voltage regulator further includes a first transistor that includes a source coupled to the output node, and a second transistor that includes a source coupled to a gate of the output transistor and a drain coupled to a second voltage supply node. The voltage regulator further includes a resistor coupled between the second voltage supply node and a first node that includes the drain of the first transistor and a gate of the second transistor. The voltage regulator further includes an error amplifier that includes a first input coupled to a reference voltage node, a second input coupled to the output node, and an output coupled to a gate of the first transistor.

An embodiment amplifier circuit includes a pair of subcircuits that includes a first subcircuit and a second subcircuit, each of which includes a buffer amplifier and a feedback circuit that includes a feedback capacitor. The amplifier circuit also includes a pair of output terminals. The first subcircuit and the second subcircuit each generate a different output signal of a pair of output signals that includes a first output signal and a second output signal. The amplifier circuit is configured for receiving a positive differential input signal at the first subcircuit, receiving a negative differential input signal at the second subcircuit, and receiving the pair of output signals at the pair of output terminals. The amplifier circuit is also configured for transmitting the first output signal to the feedback circuit of the first subcircuit, and transmitting the second output signal to the feedback circuit of the second subcircuit.