A 0.0025mm<sup>2</sup> bandgap voltage reference for 1.1V supply in standard 0.16μm CMOS

Abstract

Todays ICs usually employ one bandgap voltage reference (BGVR) circuit to generate a well defined voltage that is reused at many places in that IC. The classical BGVR generates a reference voltage that is slightly larger than the material bandgap: a little above 1200mV in silicon. For deep-sub-micron technologies the supply voltage is about the same as the material bandgap which prevents using the classical bandgap structure. As a solution a number of BGVR topologies that create a sub-1V are invented; most of them are based on the structure introduced by Banba [1], some are using resistive voltage division [2] or voltage averaging [3]. For low-power operation high-ohmic resistors (occupying a large area!) must be used in all these techniques, leading to an immediate trade-off between power consumption and chip-area. This trade-off prevents the local generation of reference voltages where they are required: either the power penalty or the area penalty would be too significant. Alternative topologies that do not require high-ohmic resistors typically are not-BGVR-based circuits relying on threshold voltages and hence require trimming to achieve low spread.