TPS2370_16 Datasheet, PDF (1/19 Pages) Texas Instruments – IEEE 802.3af POWER INTERFACE SWITCH FOR POWER OVER ETHERNET(PoE) POWERED DEVICES

TPS2370
www.ti.com
SLUS537C − AUGUST 2002 − REVISED MARCH 2004
IEEE 802.3af POWER INTERFACE SWITCH FOR
POWER OVER ETHERNET (PoE) POWERED DEVICES
FEATURES
D Integrated Power Interface Switch for IEEE
802.3af Powered Devices (PDs)
D Provides PD Detection Signature
D Provides PD Classification Signature
(Class 0−4)
D Programmable Inrush Current Limit
D Internal 0.3-Ω Low-Side FET
D Interfaces to DC/DC Soft-Start for DC/DC
Enable
D Internal Thermal Protection – Disconnects PD
Load
D Minimal External Parts Count
D 8-Pin SOIC, 8-Pin TSSOP Packages
APPLICATIONS
D VoIP Phones
D Internet Appliances
D Wireless LAN Access Points
D Bluetooth Access Points
TYPICAL APPLICATION
DESCRIPTION
Acting as an interface between the power sourcing
equipment (PSE) and the powered device (PD), the
TPS2370 performs all detection, classification, inrush
current limiting, and switch FET control that is
necessary for compliance with the IEEE 802.3af
Standard. An internal 0.3-Ω FET provides maximum
power delivery. As an additional feature, the TPS2370
interfaces with the enable/soft-start signal of a dc-to-dc
converter, eliminating the need to have an accurate
UVLO in the dc-to-dc converter.
At low input voltages (1.8 V to 10 V), the TPS2370
draws less than 12 µA, allowing accurate sensing of the
external 24.9-kΩ discovery resistor. At input voltages
between 15 V and 20 V, an external resistor sets the
level of current to be drawn during classification mode.
TPS2370 is compatible with current as well as voltage
measurement schemes for classification. Above 20-V
input, the classification current is shut off, reducing
internal power dissipation.
The TPS2370 drives an internal low-side FET for
control of the return side of the power path. The internal
FET is turned on when the input voltage reaches 40 V
and above. When the input voltage decreases, the FET
remains on until the input voltage drops to below 30 V.
SMAJ54A
V+
44 V
TO
57 V
24.9 kW
8
0.1 mf
RLIM
RCLASS
3
TPS2370
1
6
2
CDCDCIN
DC/DC
Converter/
Controller
VREG
Ethernet
Appliance
CSS
4
5
V−
UDG−03057
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. Bluetooth is a trademark of Bluetooth SIC, Inc.
PRODUCTION DATA information is current as of publication date. Products
conform to specifications per the terms of Texas Instruments standard warranty.
Production processing does not necessarily include testing of all parameters.
Copyright  2002 − 2004, Texas Instruments Incorporated