1 Features

• Enhanced ESD ride-through capability

• Optimized for isolated converters

• Complete PoE interface

• Adapter ORing support

• 12-V adapter support

• Programmable frequency with synchronization

• Robust 100-V, 0.7-Ω hotswap MOSFET

• Small 14-Pin TSSOP package

• 15-kV and 8-kV system level ESD capable

• –40°C to 125°C junction temperature range

• Design procedure application note – SLVA305

• Adapter oring application note – SLVA306

2 Applications

• IEEE 802.3at compliant powered devices

• VoIP telephones

• Access points

• Security cameras

3 Description

The TPS23753A is a combined Power over Ethernet

(PoE) powered device (PD) interface and currentmode

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

IEEE 802.3af).

The TPS23753A 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 start-up

mechanism with an internal, switched current source.

This provides the advantages of cycling overload fault

protection without the constant power loss of a pullup

resistor.

The programmable oscillator may be synchronized to

a higher-frequency external timing reference. The

TPS23753A features improvements for uninterrupted

device operation through an ESD event.