LTC4267-3
1
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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
LTC4267-3
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For more information www.linear.com/LTC4267-3
V
PORTN
with Respect to V
PORTP
Voltage .. 0.3V to100V
P
OUT
, SIGDISA, PWRGD
Voltage .....................V
PORTN
+ 100V to V
PORTN
0.3V
P
VCC
to PGND Voltage (Note 2)
Low Impedance Source ...........................0.3V to 8V
Current Fed .......................................... 5mA into P
VCC
R
CLASS
Voltage ................V
PORTN
+ 7V to V
PORTN
– 0.3V
PWRGD Current .....................................................10mA
R
CLASS
Current ....................................................100mA
NGATE to PGND Voltage ...........................0.3V to P
VCC
(Note 1)
16
15
14
13
12
11
10
9
17
1
2
3
4
5
6
7
8
V
FB
PGND
SENSE
V
PORTP
SIGDISA
PWRGD
P
OUT
NC
I
TH
/RUN
PGND
NGATE
P
VCC
R
CLASS
NC
V
PORTN
NC
TOP VIEW
DHC PACKAGE
16-LEAD (5mm × 3mm) PLASTIC DFN
T
JMAX
= 150°C, θ
JA
= 43.5°C/W
EXPOSED PAD (PIN 17) MUST BE SOLDERED TO PCB HEAT SINK.
MAY BE ELECTRICALL
Y ISOLATED OR CONNECTED TO PGND.
TOP VIEW
GN PACKAGE
16-LEAD NARROW PLASTIC SSOP
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
PGND
I
TH
/RUN
NGATE
P
VCC
R
CLASS
NC
V
PORTN
PGND
PGND
V
FB
SENSE
V
PORTP
SIGDISA
PWRGD
P
OUT
PGND
T
JMAX
= 150°C, θ
JA
= 90°C/W
LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE
LTC4267CDHC-3#PBF LTC4267CDHC-3#TRPBF 4267-3 16-Lead (5mm × 3mm) Plastic DFN 0°C to 70°C
LTC4267IDHC-3#PBF LTC4267IDHC-3#TRPBF 4267-3 16-Lead (5mm × 3mm) Plastic DFN –40°C to 85°C
LTC4267CGN-3#PBF LTC4267CGN-3#TRPBF 4267-3 16-Lead Narrow Plastic SSOP 0°C to 70°C
LTC4267IGN-3#PBF LTC4267IGN-3#TRPBF 4267I-3 16-Lead Narrow Plastic SSOP –40°C to 85°C
LEAD BASED FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE
LTC4267CDHC-3 LTC4267CDHC-3#TR 4267-3 16-Lead (5mm × 3mm) Plastic DFN 0°C to 70°C
LTC4267IDHC-3 LTC4267IDHC-3#TR 4267-3 16-Lead (5mm × 3mm) Plastic DFN –40°C to 85°C
LTC4267CGN-3 LTC4267CGN-3#TR 4267-3 16-Lead Narrow Plastic SSOP 0°C to 70°C
LTC4267IGN-3 LTC4267IGN-3#TR 4267-3 16-Lead Narrow Plastic SSOP –40°C to 85°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/
V
FB
, I
TH
/RUN to PGND Voltages ............... 0.3V to 3.5V
SENSE to PGND Voltage .............................. 0.3V to 1V
NGATE Peak Output Current (<10μs) ...........................1A
Operating Ambient Temperature Range
LTC4267C-3 ............................................. C to 70°C
LTC4267I-3 ..........................................40°C to 85°C
Junction Temperature ........................................... 150°C
Storage Temperature Range ..................6C to 150°C
Lead Temperature (Soldering, 10 sec) ...................300°C
pin conFiguraTion
absoluTe MaxiMuM raTings
orDer inForMaTion
LTC4267-3
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For more information www.linear.com/LTC4267-3
elecTrical characTerisTics
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. (Note 3)
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
PORTN
Supply Voltage
Maximum Operating Voltage
Signature Range
Classification Range
UVLO Turn-On Voltage
UVLO Turn-Off Voltage
V
oltage with Respect to V
PORTP
Pin
(Notes 4, 5, 6)
–1.5
–12.5
–34.8
–29.3
–36
–30.5
–57
–9.5
–21
–37.2
–31.5
V
V
V
V
V
V
TURNON
P
VCC
Turn-On Voltage Voltage with Respect to PGND
7.6 8.7 9.2 V
V
TURNOFF
P
VCC
Turn-Off Voltage Voltage with Respect to PGND
4.6 5.7 7 V
V
HYST
P
VCC
Hysteresis V
TURNON
– V
TURNOFF
1 3 V
V
CLAMP1mA
P
VCC
Shunt Regulator Voltage I
PVCC
= 1mA, V
ITH
/RUN = 0V, Voltage with Respect to PGND
8.3 9.4 10.3 V
V
MARGIN
V
CLAMP1mA
– V
TURNON
Margin
0.05 0.6 V
I
VPORTN_ON
V
PORTN
Supply Current when ON V
PORTN
= –48V, P
OUT
, PWRGD, SIGDISA Floating
3 mA
I
PVCC_ON
P
VCC
Supply Current
Normal Operation
Start-Up
(Note 7)
V
ITH
/RUN – PGND = 1.3V
P
VCC
– PGND = VT
URNON
– 100mV
240
40
350
90
µA
µA
I
VPORTN_
CLASS
V
PORTN
Supply Current During
Classification
V
PORTN
= –17.5V, P
OUT
Tied to V
PORTP
, R
CLASS
,
SIGDISA Floating (Note 8)
0.35 0.5 0.65 mA
ΔI
CLASS
Current Accuracy During
Classification
10mA < I
CLASS
< 40mA, –12.5V ≤ V
PORTN
≤ –21V (Note 9)
±3.5 %
R
SIGNATURE
Signature Resistance –1.5V ≤ V
PORTN
≤ –9.5V, P
OUT
Tied to V
PORTP
,
IEEE 802.3af
2-Point Measurement (Notes 4, 5)
23.25 26.00 kW
R
INVALID
Invalid Signature Resistance –1.5V ≤ V
PORTN
≤ – 9.5V, SIGDISA and P
OUT
Tied to V
PORTP
,
IEEE 802.3af 2-Point Measurement (Notes 4, 5)
9 11.8 kW
V
IH
Signature Disable
High Level Input Voltage
With Respect to V
PORTN
High Level Invalidates Signature (Note 10)
3 57 V
V
IL
Signature Disable
Low Level Input Voltage
With Respect to V
PORTN
Low Level Enables Signature
0.45 V
R
INPUT
Signature Disable, Input Resistance With Respect to V
PORTN
100 kW
V
PG_OUT
Power Good Output Low Voltage I = 1mA V
PORTN
= –48V,
PWRGD Referenced to V
PORTN
0.5 V
V
PG _FALL
V
PG_RISE
Power Good Trip Point V
PORTN
= –48V, Voltage between V
PORTN
and P
OUT
(Note 11)
P
OUT
Falling
P
OUT
Rising
1.3
2.7
1.5
3
1.7
3.3
V
V
I
PG_LEAK
Power Good Leakage Current V
PORTN
= 0V, PWRGD FET Off, V
PWRGD
= 57V
1 µA
R
ON
On-Resistance I = 300mA, V
PORTN
= –48V, Measured from V
PORTN
to P
OUT
(Note 11)
1 1.6
2
W
W
V
ITHSHDN
Shutdown Threshold (at I
TH
/RUN) P
VCC
– PGND = V
TURNON
+ 100mV
0.15 0.28 0.45 V
I
THSTART
Start-Up Current Source at I
TH
/RUN V
ITH
/RUN – PGND = 0V, P
VCC
– P
GND
= 8V 0.2 0.3 0.4 µA
V
FB
Regulated Feedback Voltage Referenced to PGND, P
VCC
– P
GND
= 8V (Note 12)
0.780 0.800 0.812 V
I
FB
V
FB
Input Current P
VCC
– P
GND
= 8V (Note 12) 10 50 nA
g
m
Error Amplifier Transconductance I
TH
/RUN Pin Load = ±5µA (Note 12) 200 333 500 µA/V
ΔV
O(LINE)
Output Voltage Line Regulation V
TURNOFF
< P
VCC
< V
CLAMP
(Note 12) 0.05 mV/V
ΔV
O(LOAD)
Output Voltage Load Regulation I
TH
/RUN Sinking 5µA, P
VCC
– P
GND
= 8V (Note 12)
I
TH
/RUN Sourcing A, P
VCC
P
GND
= 8V (Note 12)
3
3
mV/µA
mV/µA
I
POUT_LEAK
P
OUT
Leakage V
PORTN
= 0V, Power MOSFET Off, P
OUT
= 57V (Note 13)
150 µA
I
LIM_HI
Input Current Limit, High Level V
PORTN
= –48V, P
OUT
= –43V (Note 14, 15)
350 450 mA

LTC4267CDHC-3#TRPBF

Mfr. #:
Manufacturer:
Analog Devices Inc.
Description:
Power Switch ICs - POE / LAN IEEE802.3af PD w/Switching Reg.
Lifecycle:
New from this manufacturer.
Delivery:
DHL FedEx Ups TNT EMS
Payment:
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