Self-biased low leakage unity gain analog buffer

An integrated circuit, comprising:

• an input reference node that develops a reference voltage relative to first and second supply voltages;
• and
• an input/output (I/O) pad, comprising:
• a unity gain buffer, comprising:
• a buffer input node coupled to the input reference node and a buffer output node coupled to an I/O reference node, wherein the buffer input and output nodes develop a difference voltage;
• a differential amplifier having a differential input coupled to receive the difference voltage, having a control input coupled to a control node for modulating current of the differential amplifier, and having an output coupled to an output drive node;
• detector and feedback circuitry having a first input coupled to the input reference node, having a second input coupled to the I/O reference node, and having an output coupled to the control node;
• and
• an output stage having an input coupled to the output drive node and having an output coupled to the I/O reference node;
• wherein the differential amplifier is configured to draw minimal current when the difference voltage is substantially zero and wherein the detector and feedback circuitry is configured to increase the current of the differential amplifier in response to an increase of a magnitude of the difference voltage causing the output stage to drive a voltage of the I/O reference node towards a voltage of the input reference node.