A class AB operational buffer comprises an output stage, a voltage supply circuit to provide a first voltage and a second voltage to drive the output stage, a first current source to provide a first current, a second current source to provide a second current, a first current mirror having a first reference branch coupled with the first current and a first mirror branch coupled with the second current through the voltage supply circuit, and a second current mirror having a second reference branch coupled between the second current source and first mirror branch and a second mirror branch coupled between the first current source and first reference branch.