A supply insensitive resistor-less bandgap reference with buffered output

Abstract

This paper describes a bandgap reference that doesn't use resistors or operational amplifiers. The circuit uses ratioed transistors in strong inversion with the inverse function technique to develop a voltage, proportional to the absolute temperature term of the reference. With the low-output impedance at the output, this reference voltage can drive resistive loads. Unlike its predecessor, this circuit's performance doesn't degrade with variations in supply voltage. The bandgap was designed on a 0.6μm process and the corresponding BSIM3 (V3.2) models are used.