ZHCSJO9A May 2019 – November 2019 TL431LI-Q1 , TL432LI-Q1
PRODUCTION DATA.
TL43xLI-Q1 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 is VREF = VIN - IREFRIN. Because IREF can be as high as 0.4 µA, it is recommended to use a resistance small enough that mitigates the error that IREF creates from VIN.