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.