The low dropout (LDO) voltage regulator brings the advantage of power savings to system design by reducing the voltage required to maintain output regulation. However, the traditional LDO has always brought with it the disadvantage of placing tight restrictions on the equivalent series resistance (ESR) of the output capacitor in order to keep the regulator stable. This requirement has been eliminated by National Semiconductor’s new line of FlexCap LDOs, which are stable with any type of output capacitor.
This paper enumerates the advantages of using FlexCap LDOs and demonstrates that the internal compensation used in FlexCap products can maintain stability regardless of the ESR of the output capacitor.