PM8803 STMicroelectronics, PM8803 Datasheet - Page 24

• Manufacturer Part Number: PM8803
• Description: High efficiency integrated IEEE 802.3at PoE-PD interface and PWM controller type 2 PSE indicator, plus support for forward active clamp topology
• Manufacturer: STMicroelectronics

PD interface
4.7
24/34
5 V bias regulator
The PM8803 features an accurate 5 V output regulator, which can be used to bias the
DC/DC feedback network and the optocoupler connected to the microcontroller.
A capacitor in the range of 100 nF - 2.2 µF must be connected to ARTN for stability.
The regulator current is supplied from the VC pin, to take advantage of the more efficient
bias from the auxiliary winding. This means that the current drawn from the VB pin must be
taken into account to evaluate the maximum current drawn from the VC pin
The current drawn from the VB pin must be limited to 10 mA maximum.
The VB regulator is also able to accept injected current up to 1 mA without losing voltage
regulation.
Doc ID 018559 Rev 1
PM8803