On the limit of operational amplifiers’ supply voltage

Abstract

Power-supply and threshold voltages are getting smaller at every technology node. The impact of this reduction in the main building block of analog circuits, the operational amplifier, is studied. In order to develop a technology which is not yet available, extensive Technology CAD (TCAD) simulations are performed. After process optimization based upon digital circuit objectives, the resulting transistor models are used to build a rail-to-rail (both at input and output) operational amplifier that can operate from a supply voltage as low as 0.5 V. The resultssuggest that the amplifier’s performance is similar to whatwe can obtain today at much higher supply voltages (for thesame power consumption).