LTC4264
High Power PD Interface
Controller with 750mA
Current Limit
FEATURES DESCRIPTION
Complete High Power PD Interface Controller
The LTC 4264 is an integrated Powered Device (PD) in-
IEEE 802.3af Compliant
terface controller intended for IEEE 802.3af Power over
Onboard 750mA Power MOSFET
Ethernet (PoE) and high power PoE applications up to 35W.
Complementary Power Good Outputs
By including a precision dual current limit, the LTC4264
Flexible Auxiliary Power Options
keeps inrush below the IEEE802.3af current limit levels
Precision Dual Current Limit with Disable
to ensure interoperability success while allowing for high
Programmable Classi cation Current to 75mA
power PD operation. The LTC4264 includes a eld-proven
Onboard 25k Signature Resistor with Disable
power MOSFET delivering up to 750mA to the PD load while
Undervoltage Lockout
maintaining compliance with the IEEE802.3af standard.
Complete Thermal Overload Protection
Complementary power good outputs allow the LTC4264 to
Available in Low Pro le (4mm 3mm) DFN Package
interface directly with a host of DC/DC converter products.
The LTC4264 provides a complete signature and power
APPLICATIONS
interface solution for PD designs by incorporating the 25k
signature resistor, classi cation circuitry, input current
802.11n Access Points
limit, undervoltage lockout, thermal overload protection,
High Power VoIP Video Phones
signature disable and power good signaling.
RFID Reader Systems
PTZ Security Cameras and Surveillance Equipment The LTC4264 PD interface controller can be used along with
a variety of Linear Technology DC/DC converter products
to provide a complete, cost effective power solution for
high power PD applications.
The LTC4264 is available in the space-saving low pro le
(4mm 3mm) DFN package.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
TYPICAL APPLICATION
Turn On vs Time
V C = 100F
LOAD
IN
50V/DIV
~ +
LTC4264
54V FROM V
0.1F IN
DF1501S
+
SHDN
DATA PAIR GND V
5F SWITCHING OUT
SMAJ58A
~ 50V/DIV
MIN
POWER
R PWRGD
CLASS SUPPLY
+
R
PWRGD RUN
CLASS
PWRGD V
~ +
OUT
3.3V
RTN
54V FROM 50V/DIV
I
DF1501S TO LOGIC
LIM_EN
SPARE PAIR
V V
~ IN OUT
4264 TA01a
I
IN
200mA/DIV
TIME (5ms/DIV)
4264 TA01b
4264f
1LTC4264
ABSOLUTE MAXIMUM RATINGS PACKAGE/ORDER INFORMATION
(Notes 1, 2)
TOP VIEW
V Voltage ................................................. 0.3V to 90V
IN
V Voltage ......... V + 90V (and GND) to V 0.3V SHDN 1 12 GND
OUT IN IN
SHDN Voltage ............................ V + 90V to V 0.3V NC 2 11 NC
IN IN
R , I Voltage ............... V + 7V to V 0.3V R 3 10 PWRGD
CLASS
CLASS LIM_EN IN IN
13
I 4 9 PWRGD
PWRGD Voltage (Note 3)
LIM_EN
V 5 8 V
Low Impedance Source ....V + 11V to V 0.3V IN OUT
OUT OUT
V 6 7 V
Current Fed ..........................................................5mA IN OUT
PWRGD Voltage ......................... V + 80V to V 0.3V
IN IN
DE12 PACKAGE
12-LEAD (4mm 3mm) PLASTIC DFN
PWRGD Current .....................................................10mA
T = 150C, = 43C/W, = 4.3C/W
JMAX JA JC
R Current .....................................................100mA
CLASS
EXPOSED PAD (PIN 13) MUST BE SOLDERED TO
AN ELECTRICALLY ISOLATED HEAT SINK
Operating Ambient Temperature Range
LTC4264C ................................................ 0C to 70C
ORDER PART NUMBER DE PART MARKING*
LTC4264I ............................................. 40C to 85C
LTC4264CDE 4264
Junction Temperature ........................................... 150C
LTC4264IDE 4264
Storage Temperature Range ................... 65C to 150C
Order Options Tape and Reel: Add #TR
Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF
Lead Free Part Marking: