ZHCSHL4I October 2008 – December 2017 TPS23754 , TPS23754-1 , TPS23756
PRODUCTION DATA.
DEN is a multifunction pin for PoE detection and inhibiting operation from PoE power. Connect a 24.9-kΩ resistor from DEN to VDD to provide the PoE detection signature. DEN goes to a high-impedance state when VVDD-VSS is outside of the detection range. Pulling DEN to VSS during powered operation causes the internal hotswap MOSFET and class regulator to turn off, while the reduced detection resistance prevents the PD from properly redetecting.