Partial cascode in combination with full cascode operational transconductance amplifier

A method comprising:

• generating an output current in response to a differential input voltage and associated with an output transconductance;
• and
• selectively increasing the output transconductance from a first value to a second value in response to a control signal,
• wherein a first value of the control signal enables a first partial cascode circuit coupled in parallel to a second partial cascode circuit and a second value of the control signal disables the first partial cascode circuit.

An amplifier circuit comprising:

• a full cascode circuit coupled to an output node;
• a first partial cascode circuit coupled to a first node and coupled between the full cascode circuit and a first power supply node;
• and
• a second partial cascode circuit coupled to the first node and coupled between the full cascode circuit and the first power supply node;
• and
• a switch circuit responsive to a control signal to selectively enable the second partial cascode circuit.