LTC4267-3
1
42673fb
For more information www.linear.com/LTC4267-3
Power over Ethernet
IEEE 802.3af PD Interface with
Integrated Switching Regulator
The LT C
®
4267-3 combines an IEEE 802.3af compliant
Powered Device (PD) interface with a 300kHz current mode
switching regulator, providing a complete power solution
for PD applications. The LTC4267-3 integrates the 25k
signature resistor, classification current source, thermal
overload protection, signature disable and power good
signal along with an undervoltage lockout optimized for
use with the IEEE-required diode bridge. The LTC4267-3
provides an increased operational current limit, maximizing
power available for class 3 applications.
The 300kHz current mode switching regulator provides
higher output power or smaller external size compared
to its lower frequency counterparts. The LTC4267-3 is
designed for driving a 6V rated N-channel MOSFET and
features programmable slope compensation, soft-start,
and constant-frequency operation, minimizing noise even
with light loads. The LTC4267-3 includes an onboard er
-
ror amplifier and voltage reference allowing use in both
isolated and nonisolated configurations
.
The
LTC4267-3 is available in a space saving, low profile
16-pin SSOP or DFN packages.
n
IP Phone Power Management
n
Wireless Access Points
n
Security Cameras
n
Power over Ethernet
n
Complete Power Interface Port for IEEE 802
®
.3af
Powered Device (PD)
n
Onboard 100V, UVLO Switch
n
Constant-Frequency 300kHz Operation
n
Precision Dual Level Inrush Current Limit
n
Integrated Current Mode Switching Regulator
n
Onboard 25k Signature Resistor with Disable
n
Programmable Classification Current (Class 0-4)
n
Thermal Overload Protection
n
Power Good Signal
n
Integrated Error Amplifier and Voltage Reference
n
Low Profile 16-Pin SSOP or DFN Packages
Class 2 PD with 3.3V Isolated Power Supply
P
VCC
PWRGD
NGATE
SENSE
I
TH
/RUN
V
FB
PGND
P
OUT
V
PORTP
R
CLASS
SIGDISA
V
PORTN
LTC4267-3
+
+
R
CLASS
68.1Ω
1%
5µF
MIN
10k
470Ω
100k
60.4k
P
VCC
P
VCC
4.7µF
320µF
MIN
22nF
•
•
PA1133
PS2911
BAS516
TLV431
SBM1040
SMAJ58A
3.3V
1.5A
CHASSIS
HD01
+
–
+
–
HD01
–48V
FROM
DATA PAIR
–48V
FROM
SPARE PAIR
42671 TA01
Si3440
0.1Ω
6.8k
10k
0.1µF
L, LT , LT C , LT M , Linear Technology and the Linear logo are registered trademarks and
LTPoE
++
is a trademark of Linear Technology Corporation. All other trademarks are the property
of their respective owners.
Typical applicaTion
FeaTures DescripTion
applicaTions