SLVS543S August 2004 – May 2024 TL431 , TL432
PRODUCTION DATA
TL431 requires an input resistance in this application to source the reference current (IREF) needed from this device to be in the proper operating regions while turning on. The actual voltage seen at the ref pin will be VREF=VIN-IREF*RIN. Since IREF can be as high as 4µA it is recommended to use a resistance small enough that will mitigate the error that IREF creates from VIN.