Polyphase filter circuitry including: an input node to receive an input signal V.sub.IN having a dominant frequency f.sub.PPF; and a common-source amplifier circuit. The common-source amplifier circuit includes a field-effect transistor M1 with its gate terminal connected to the input node and with a capacitor C.sub.PFF connected to its source terminal; and for the common-source amplifier circuit, the output resistance R.sub.M1 at the source terminal of the field-effect transistor M1 and the capacitance of the capacitor C.sub.PFF are define the frequency response of the common-source amplifier circuit so that, based on the input signal V.sub.IN, a signal V.sub.LEAD is generated at the drain terminal of the transistor M1 which leads the input signal V.sub.IN in phase by a given phase shift .sub.LEAD and a signal V.sub.LAG is generated at the source terminal of the transistor M1 which lags the input signal V.sub.IN in phase by a given phase shift .sub.LAG.

The present disclosure relates to circuitry comprising audio amplifier circuitry for receiving an audio signal to be amplified; and first and second output nodes for outputting first and second differential output signals. The circuitry further comprises common mode buffer circuitry configured to receive a common mode voltage and to selectively output the common mode voltage to the first and second output nodes.

A circuit includes: a low-pass filter that includes a resistor coupled between a first node and a second node, and a capacitor coupled between the second node and a reference node. The circuit further includes: a first transistor, where a drain terminal of the first transistor is coupled to the second node, and a source terminal of the first transistor is coupled to the first node; and a second transistor, where a drain terminal of the second transistor is coupled to the first node, and a source terminal of the second transistor is coupled to the reference node, where a gate terminal of the first transistor and a gate terminal of the second transistor are coupled to a control node.

A circuit includes: a low-pass filter that includes a resistor coupled between a first node and a second node, and a capacitor coupled between the second node and a reference node. The circuit further includes: a first transistor, where a drain terminal of the first transistor is coupled to the second node, and a source terminal of the first transistor is coupled to the first node; and a second transistor, where a drain terminal of the second transistor is coupled to the first node, and a source terminal of the second transistor is coupled to the reference node, where a gate terminal of the first transistor and a gate terminal of the second transistor are coupled to a control node.