1FEATURES

• Optimized for Isolated Converters

• Complete PoE Interface

• Adapter ORing Support

• 12 V Adapter Support

• Programmable Frequency with Synch.

• Robust 100 V, 0.7 Ω Hotswap MOSFET

• Small TSSOP 14 Package

• 15 kV / 8 kV System Level ESD Capable

• –40°C to 125°C Junction Temperature Range

• Design Procedure Application Note - SLVA305

• Adapter ORing Application Note - SLVA306

APPLICATIONS

• IEEE 802.3at Compliant Powered Devices

• VoIP Telephones

• Access Points

• Security Cameras

DESCRIPTION

The TPS23753 is a combined Power over Ethernet

(PoE) powered device (PD) interface and

current-mode dc/dc controller optimized specifically

for isolated converter designs. The PoE

implementation supports the IEEE 802.3at standard

as a 13 W, type 1 PD. The requirements for an IEEE

802.3at type 1 device are a superset of IEEE 802.3-2008 (originally 802.3af) requirements.

The TPS23753 supports a number of input-voltage

ORing options including highest voltage, external

adapter preference, and PoE preference.

The PoE interface features an external detection

signature pin that can also be used to disable the

internal hotswap MOSFET. This allows the PoE

function to be turned off. Classification can be

programmed to any of the defined types with a single

resistor.

The dc/dc controller features a bootstrap startup

mechanism with an internal, switched current source.

This provides the advantages of cycling overload fault

protection without the constant power loss of a pull up

resistor.

The programmable oscillator may be synchronized to

a higher-frequency external timing reference.