Low noise, low distortion MOS amplifier circuit

An MOS amplifier circuit comprising:

• a first series combination of main current paths of a first and a second MOS transistor, wherein an input of the amplifier circuit is coupled to a gate electrode of the first transistor, and a gate electrode of the second transistor is coupled to its drain electrode;
• and
• a second series combination of main current paths of a third and a fourth MOS transistor that is identical to the first series combination, wherein another input of the amplifier circuit is coupled to a gate electrode of the third MOS transistor, source electrodes of the first and third MOS transistors are intercoupled and are coupled to a first current source, drain electrodes of the second and fourth MOS transistors being intercoupled, drain electrodes of the first and third transistors being connected to a differential amplifier, an output of the deferential amplifier being coupled to an output of the amplifier circuit and also, via a series combination of a first and a second resistor, to the drain electrodes of the second and fourth MOS transistors, and a junction of the first and second resistors is coupled to a gate electrode of the fourth transistor, and in that the first to fourth MOS transistors are mutually identical.