SLUSCD1C June 2017 – November 2018 TPS2373
PRODUCTION DATA.
Refer to the PDF data sheet for device specific package drawings
The APD pin is used in applications that may draw power either from the Ethernet cable or from an auxiliary power source. When a voltage of more than about 1.65 V is applied on the APD pin relative to RTN, the TPS2373 does the following:
This also gives adapter source priority over the PoE. A resistor divider (RAPD1–RAPD2 in Figure 30) provides system-level ESD protection for the APD pin, discharges leakage from the blocking diode (DA in Figure 30) and provides input voltage supervision to ensure that switch-over to the auxiliary voltage source does not occur at excessively low voltages. If not used, connect APD to RTN.
Note that RAPD2 must be no more than 200 kΩ.