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Linear Technology Demonstration circuit 1351A single output, high power, high efficency POE DC1351A DC1351A Data Sheet

Product codes
DC1351A
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Page of 34
LTC4269-2

42692fb
Typical applicaTion
FeaTures
applicaTions
DescripTion
IEEE 802.3at High Power PD 
and Synchronous Forward 
Controller with AUX Support
The LTC
®
4269-2 is an integrated Powered Device (PD)  
interface and power supply controller featuring 2-event 
classification  signaling,  flexible  auxiliary  power  op-
tions, and a power supply controller suitable for syn-
chronously rectified forward supplies. These features 
make the LTC4269-2 ideally suited for an IEEE802.3at 
PD application.
The PD controller features a 100V MOSFET that isolates 
the power supply during detection and classification, and 
provides 100mA inrush current limit. Also included are 
power good outputs, an undervoltage/overvoltage lock-
out and thermal protection. The current mode forward 
controller allows for synchronous rectification, resulting 
in an extremely high efficiency, green product. Soft-start 
for controlled output voltage start-up and fault recovery is 
included. Programmable frequency over 100kHz to 500kHz 
allows flexibility in efficiency vs size and low EMI.
n
  25.5W IEEE 802.3at Compliant (Type-2) PD
n
  PoE
+
 2-Event Classification
n
  IEEE 802.3at 
High Power Available Indicator
n
  Integrated State-of-the-Art Synchronous Forward 
Controller
  –  Isolated Power Supply Efficiency >94%
n
  Flexible Auxiliary Power Interface
n
  Superior EMI Performance
n
  Robust 100V 0.7Ω (Typ) Integrated Hot Swap™ 
MOSFET
n
  Integrated Signature Resistor, Programmable Class 
Current, UVLO, OVLO and Thermal Protection
n
  Short-Circuit Protection with Auto-Restart
n
  Programmable Switching Frequency from  
100kHz to 500kHz
n
  Thermally Enhanced 7mm 
× 4mm DFN Package
n
  IP Phones with Large Color Screens
n
  Dual Radio 802.11n Access Points
n
  PTZ Security Cameras
+
T2P V
NEG
V
PORTN
SHDN
R
CLASS
V
PORTP
PGND
TO
MICRO-
CONTROLLER
GND BLANK DELAY
82k
30.9Ω
332k 158k
133Ω
10k
5.1Ω
158k
22.1k
33k
1.5k
50mΩ
2k
1.2k
TLV431
V
CC
11.3k
3.65k
42692 TA01
22k
0.22µF
0.1µF
R
OSC
V
REF
FB
COMP
I
SENSE
OC
SS_MAXDC
SD_V
SEC
V
IN
PWRGD
S
OUT
LTC4269-2
0.1µF
10µF
V
CC
33k
237k
2.2µF
+
10µF
10µH
1mH
6.8µH
10.0k
OUT
4.7nF
0.1µF
54V FROM
DATA PAIR
54V FROM
SPARE PAIR
+
–
~
~
+
–
~
~
4.7nF
•
•
•
10nF
+
220µF
5V
5A
PoE-Based Self-Driven Synchronous Forward Power Supply
L
, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and  
Hot Swap, ThinSOT are trademarks of Linear Technology Corporation. All other trademarks  
are the property of their respective owners.