LTC4267-1_15 Datasheet, PDF (1/32 Pages) Linear Technology – Power over Ethernet IEEE 802.3af PD Interface with Integrated Switching Regulator

LTC4267-1
Features
Power over Ethernet
IEEE 802.3af PD Interface with
Integrated Switching Regulator
Description
n _{Complete Power Interface Port for IEEE 802}^®_.3af
Powered Device (PD)
n _{Onboard 100V, UVLO Switch}
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 Package}
Applications
n _{IP Phone Power Management}
n _{Wireless Access Points}
n _{Security Cameras}
n _{Power over Ethernet}
L, LT, LTC, LTM, 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.
The LTC^®4267-1 combines an IEEE 802.3af compliant
Powered Device (PD) interface with a current mode switch-
ing regulator, providing a complete power solution for PD
applications. The LTC4267-1 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 LTC4267-1 provides an
increased operational current limit, maximizing power
available for class 3 applications.
The current mode switching regulator is designed for
driving a 6V rated N-channel MOSFET and features pro-
grammable slope compensation, soft-start, and constant
frequency operation, minimizing noise even with light
loads. The LTC4267-1 includes an onboard error amplifier
and voltage reference allowing use in both isolated and
nonisolated configurations.
The LTC4267-1 is available in a space saving, low profile
16-pin SSOP package.
Typical Application
Class 2 PD with 3.3V Isolated Power Supply
PA1133 SBM1040
–48V
FROM
DATA PAIR
+
HD01
–
–48V
FROM
SPARE PAIR
+
HD01
–
V_PORTP
P_VCC
SMAJ58A
PWRGD
LTC4267-1
NGATE
0.1µF
SENSE
R_CLASS
68.1Ω
1%
R_CLASS I_TH/RUN
V_FB
SIGDISA PGND
V_PORTN
P_OUT
10k
•
+
P_VCC ⁺ _5µF
4.7µF
MIN
320µF
• ^MIN
10k ^Si3440
P_VCC
6.8k
0.1Ω
BAS516
PS2911
470Ω
22nF
3.3V
1.5A
CHASSIS
100k
For more information www.linear.com/4267-1
TLV431
60.4k
42671 TA01
42671fa
1