LTC4265_15 Datasheet, PDF (1/22 Pages) Linear Technology – IEEE 802.3 at High Power PD Interface Controller with 2-Event Classification Recognition

LTC4265
IEEE 802.3 at High Power PD
Interface Controller with
2-Event Classification Recognition
Features
n _{IEEE 802.3af/at Powered Device (PD) Controller}
n _{IEEE 802.3at 2-event Classification Signaling}
n _{Programmable Classification Current}
n _{Flexible Auxiliary Power Support Using SHDN Pin}
n _{Rugged 100V Onboard MOSFET with 100mA Inrush}
Current Limit.
n _{Complementary Power Good Outputs}
n _{Onboard Signature Resistor}
n _{Comprehensive Thermal Protection}
n _{Undervoltage and Overvoltage Lockout}
n _{12-Lead, 4mm × 3mm DFN Package}
Applications
n _{802.11n Access Points}
n _{High Power VoIP Video Phones}
n _{RFID Reader Systems}
n _{PTZ Security Cameras and Surveillance Equipment}
Description
The LTC^®4265 is a 3rd generation Powered Device (PD)
Interface controller intended for IEEE 802.3at high power
Power-over-Ethernet (PoE) applications up to 25.5W. By
supporting 1-event and 2-event classification signaling as
defined by IEEE 802.3, the LTC4265 can be used in a wide
range of product configurations. A 100V MOSFET isolates
the DC/DC converter during detection and classification,
and provides 100mA inrush current for a smooth power-up
transition. The LTC4265 also includes complementary
power good outputs, an on-board signature resistor,
undervoltage/overvoltage lockout and comprehensive
thermal protection. All Linear Technology PD solutions
include a shutdown pin with signature corrupt to provide
flexible auxiliary power options.
The LTC4265 PD interface controller can be used along
with a variety of DC/DC converter products to provide a
complete, cost effective power solution for high power
PD applications.
The LTC4265 is available in the space-saving low profile
(4mm × 3mm) DFN package and is drop-in compatible
with the LTC4264.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
Typical Application
~+
54V FROM
0.1µF
DATA PAIR
~–
~+
54V FROM
SPARE PAIR _~
–
TO AUX
LTC4265
GND
R_CLASS PWRGD
R_CLASS
PWRGD
SHDN
V_IN
V_OUT
T2PSE
5µF ⁺
MIN
V⁺
SWITCHING
POWER
SUPPLY
RUN
RTN
+
3.3V
TO LOGIC
–
TO LOGIC
4265 TA01a
GND – V_IN
50V/DIV
GND – V_OUT
50V/DIV
PWRGD – V_OUT
50V/DIV
I_PD
100mA/DIV
For more information www.linear.com/LTC4265
Turn-On vs Time
C_LOAD = 100µF
TIME
25ms/DIV
4265 TA01b
4265fb
1