PM8800A_08 Datasheet, PDF (1/35 Pages) STMicroelectronics – Integrated IEEE 802.3af compliant PoE-PD interface and PWM controller with support of external source

PM8800A
Integrated IEEE 802.3af compliant PoE-PD interface
and PWM controller with support of external source
Features
■ IEEE 802.3af compliant PD interface
■ Works with power supplied from Ethernet LAN
cables or from local auxiliary sources
■ Integrated 100 V, 0.5 Ω, 800 mA hot-swap
MOSFET
■ Integrated signature resistor
■ Programmable in-rush current limit
■ Programmable classification current
■ Programmable DC current limit up to 800 mA
■ High voltage start-up bias regulator
■ Thermal shutdown protection
■ Current mode pulse width modulator
■ Programmable oscillator frequency
■ Programmable soft-start
■ Power good indication
■ 80 % maximum duty cycle with internal slope
compensation
■ Supports both isolated and non-isolated
Applications.
■ HTSSOP16 package
Applications
■ VoIP phones, WLAN access points
■ Security cameras
■ PoE powered device appliances
■ High power (>12.95 W) powered devices
HTSSOP16
Description
The PM8800A integrates a standard power over
Ethernet (PoE) interface and a current mode
PWM controller to simplify the design of the
power supply sections of all powered devices.
The PoE interface incorporates all the functions
required by the IEEE 802.3af including detection,
classification, under-voltage lockout (UVLO) and
in-rush current limitation.
PM8800A specifically targets PD with extended
power requirement with respect to the limit
imposed by the 802.3af standard, embedding a
hot-swap MOSFET capable of sustaining twice
the current of the 802.3af standard with a
programmable DC current limit.
The integrated switching regulator has been
designed to work with power either form the
Ethernet cable connection or from an external
power source such as AC adapter.
The DC-DC section of the PM8800A features a
programmable oscillator frequency, soft-start,
slope compensation and embeds a voltage output
error amplifier allowing use in both isolated and
non isolated configuration.
Table 1. Device summary
Order codes
PM8800A
PM8800ATR
Package
HTSSOP16
HTSSOP16
Packing
Tube
Tape and reel
February 2008
Rev 2
1/35
www.st.com
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