TPS23785B Datasheet, PDF (1/47 Pages) Texas Instruments – High-Power, High-Efficiency PoE PD and DC-to-DC Controller

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TPS23785B
SLUSB90A – DECEMBER 2012 – REVISED DECEMBER 2012
High-Power, High-Efficiency PoE PD and DC-to-DC Controller
FEATURES
1
•2 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
APPLICATIONS
• IEEE 802.3at Compliant Devices
• Video and VoIP Telephones
• RFID Readers
• Surveillance Cameras
• Wireless Access Points
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.
Typical Application Diagram
DA
RAPD1
Type 2 PSE
Indicator
DEN
NC
CLS
T2P
VC
V_B
RT2P
PAD _TPS23785B
VSS
APD
CTL
FRS
GATE
CS
GAT2
R_VC
M1
T1
CIN
DVC1
M2
CIZ
TLV431
V_OUT
1
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PowerPAD is a trademark of Texas Instruments.
2
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2012, Texas Instruments Incorporated