PM8800 STMicroelectronics, PM8800 Datasheet - Page 15

• Manufacturer Part Number: PM8800
• Description: Integrated IEEE 802.3af compliant PoE-PD interface and PWM controller with support of external source
• Manufacturer: STMicroelectronics

PM8800A
Device description and operation
PM8800A can work with power either from PoE networks or from auxiliary sources - like AC
adapters -. Alternative sources are present in PoE appliances where devices can work also
outside the context of the PoE networks or to ensure normal operation even if PoE becomes
unavailable. PM8800A limits the number of external components to handle the coexistence
of both PoE and auxiliary supplies.
External sources can be connected so to exploit the in-rush current limitation provided by
the MOSFET or enabling the PWM section, bypassing the interface section.
A state-of-the-art current mode pulse with modulator is embedded in the PM8800A to sup-
port low side single ended isolated and non isolated topologies. A high gain bandwidth prod-
uct error amplifier is embedded for non isolated configuration.
PM8800A has a 80 % maximum duty cycle, featuring embedded slope compensation.
The PWM switching frequency of PM8800A is programmable with an appropriate resistor
and it is also capable of working with an external clock reference.
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