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Product details

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Package | Pins | Size

HTSSOP (PWP) 24 34 mm² 7.7 x 4.4 open-in-new Find other Powered devices

Features

  • Powers up to 30-W (Input) PDs
  • DC-to-DC Control Optimized for Non-Isolated Converters
  • Supports High-Efficiency Topologies
  • Complete PoE Interface
  • Enhanced Classification per IEEE 802.3at with Status Flag
  • Adapter ORing Support
  • Robust 100-V, 0.5-Ω Hotswap MOSFET
  • –40°C to 125°C Junction Temperature Range
  • Industry Standard PowerPAD TSSOP-24
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Description

The TPS23785B is a combined Power over Ethernet (PoE) powered device (PD) interface and current-mode DC-to-DC controller optimized specifically for non-isolated converters. The PoE interface supports the IEEE 802.3at standard.

The TPS23785B supports a number of input voltage ORing options including highest voltage, external adapter preference, and PoE preference. These features allow the designer to determine which power source will carry the load under all conditions.

The PoE interface features the two-event, physical-layer classification necessary for compatibility with high-power midspan power sourcing equipment (PSE) per IEEE 802.3at. The detection signature pin can also be used to force power from the PoE source off. Classification can be programmed to any of the defined types with a single resistor.

The DC-to-DC controller features two complementary gate drivers with programmable dead time. This simplifies design for highly-efficient flyback topologies utilizing secondary synchronous rectification. The second gate driver may be disabled if desired for single MOSFET topologies. The controller also features internal softstart, bootstrap startup source, current-mode compensation, and a 78% maximum duty cycle. A programmable and synchronizable oscillator allows design optimization for efficiency and eases use of the controller to upgrade existing power supply designs. Accurate programmable blanking, with a default period, simplifies the usual current-sense filter design trade-offs.

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Special note

Active – Limited TI design support

This product has limited direct TI design support for existing projects. If available, you can find relevant collateral and software on the product folder. For existing designs using this product, you may request support in the TI E2E support forums, but limited support is available for this product.

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Similar but not functionally equivalent to the compared device:
TPS23754 ACTIVE IEEE 802.3at, high efficiency, PoE interface and DC/DC controller This product has higher performance and better collateral support.

Technical documentation

= Top documentation for this product selected by TI
No results found. Please clear your search and try again. View all 7
Type Title Date
* Datasheet High-Power, High-Efficiency PoE PD and DC-to-DC Controller datasheet (Rev. A) Dec. 18, 2012
Application notes Lightning Surge Considerations for PoE Powered Devices Apr. 30, 2015
User guides TPS23785BEVM-522 Evaluation Module Apr. 25, 2014
Application notes Efficiency-Optimized, Synchronous Flyback, High-Power PoE Controller/Converter Jan. 17, 2012
Application notes High Efficiency Class 4 PoE Powered Device Mar. 23, 2011
Application notes Advanced Adapter ORing Solutions using the TPS23753 (Rev. A) Feb. 09, 2009
Application notes Designing an EMI Compliant PoE with Isolated Flyback May 20, 2008

Design & development

For additional terms or required resources, click any title below to view the detail page where available.

Design tools & simulation

SIMULATION TOOLS Download
PSpice® for TI design and simulation tool
PSPICE-FOR-TI — PSpice® for TI is a design and simulation environment that helps evaluate functionality of analog circuits. This full-featured, design and simulation suite uses an analog analysis engine from Cadence®. Available at no cost, PSpice for TI includes one of the largest model libraries in the (...)
Features
  • Leverages Cadence PSpice Technology
  • Preinstalled library with a suite of digital models to enable worst-case timing analysis
  • Dynamic updates ensure you have access to most current device models
  • Optimized for simulation speed without loss of accuracy
  • Supports simultaneous analysis of multiple products
  • (...)
CALCULATION TOOLS Download
SLUC480.ZIP (452 KB)

Reference designs

REFERENCE DESIGNS Download
Class 3 - Mulitple Output, High Efficiency Driven Flyback Converter for PoE Applications
PMP8408 This converter is used for Class 3 PoE applications where high efficiency and multiple outputs are required. The flyback converter with synchronous rectifier provides excellent efficiency and small size for PoE applications such as IP Phones. The TPS23785B contains both the PoE Powered Device (...)
document-generic Schematic document-generic User guide
REFERENCE DESIGNS Download
Class 3 - Mulitple Output, High Efficiency Self-Driven Flyback Converter for PoE Applications
PMP8454 — This converter is used for Class 3 PoE applications where high efficiency and multiple outputs are required. PMP8454.1 has an output of 3.3V@2A. The flyback converter with synchronous rectifier provides excellent efficiency and small size for PoE applications such as a IP Phones. The TPS23785B (...)
REFERENCE DESIGNS Download
Class 1 Mulitple Output High Efficiency Flyback Converter for PoE Applications Reference Design
PMP8752 This converter is used for Class 1 PoE applications where high-efficiency and multiple-outputs are required. The multi-outputs for this design are 3.3V/0.7A, 5V/0.145A, 3.3V/1.5A. The flyback converter with synchronous rectifier provides excellent efficiency, and small size for PoE applications (...)
document-generic Schematic document-generic User guide
REFERENCE DESIGNS Download
Class 2 Mulitple Output, High Efficiency Flyback Converter for PoE Applications
PMP8407 This reference evaluation module, featuring the TPS23785B PoE interface and DC-toDC contoller, is used for class 2 PoE applications where high effliency and multiple outputs are required.

The flyback converter with synchronous reftifier provides excellent efficiency and small size for PoE (...)

document-generic Schematic document-generic User guide

CAD/CAE symbols

Package Pins Download
HTSSOP (PWP) 24 View options

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