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LT4276BHUFD#PBF

P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P21P22-P24P25-P26
LT4276
1
4276fa
For more information www.linear.com/LT4276
Typical applicaTion
FeaTures DescripTion
LTPoE
++
/PoE
+
/PoE
PD Forward/Flyback Controller
The LT
®
4276 is a pin-for-pin compatible family of IEEE
802.3 and LTPoE
++
Powered Device (PD) controllers. It
includes an isolated switching regulator controller capable
of synchronous operation in both forward and flyback
topologies with auxiliary power support.
The LT4276A employs the LTPoE
++
classification scheme,
receiving 38.7W, 52.7W, 70W or 90W of power at the PD
RJ45 connector, and is backwards compatible with IEEE
802.3. The LT4276B is a fully 802.3at compliant, 25.5W
Type 2 (PoE
+
) PD. The LT4276C is a fully 802.3af compli
-
ant, 13W Type 1 (PoE) PD.
The LT4276 supports both for
ward and flyback power
supply topologies, configurable for a wide range of PoE
applications. The flyback topology supports No-Opto
feedback. Auxiliary input voltage can be accurately sensed
with just a resistor divider connected to the AUX pin.
The LT4276 utilizes an external, low R
DS(ON)
N-channel
MOSFET for the Hot Swap function, maximizing power
delivery and efficiency, reducing heat dissipation, and
easing the thermal design.
LTPoE
++
70W Power Supply in a Forward Mode
applicaTions
n
IEEE802.3af/at and LTPoE
++
™
90W Powered Device
(PD) with Forward/Flyback Controller
n
LT4276A Supports All of the Following Standards:
n
LTPoE
++
38.7W, 52.7W, 70W and 90W
n
IEEE 802.3at 25.5W Compliant
n
IEEE 802.3af up to 13W Compliant
n
LT4276B is IEEE 802.3at/af Compliant
n
LT4276C is IEEE 802.3af Compliant
n
Superior Surge Protection (100V Absolute Maximum)
n
Wide Junction Temperature Range (–40°C to 125°C)
n
Auxiliary Power Support as Low as 9V
n
No Opto-Isolator Required for Flyback Operation
n
External Hot Swap
™
N-Channel MOSFET for Lowest
Power Dissipation and Highest System Efficiency
n
>94% End-to-End Efficiency with LT4321 Ideal Bridge
n
Available in a 28-Lead 4mm × 5mm QFN Package
n
High Power Wireless Data Systems
n
Outdoor Security Camera Equipment
n
Commercial and Public Information Displays
n
High Temperature Applications
L, LT, LTC, LTM, LTPoE
++,
Linear Technology and the Linear logo are registered trademarks of
Linear Technology Corporation. All other trademarks are the property of their respective owners.
LT4276 Family
MAX DELIVERED
POWER
LT4276
GRADE
A B C
LTPoE
++
90W
l
LTPoE
++
70W
l
LTPoE
++
52.7W
l
LTPoE
++
38.7W
l
25.5W
l l
13W
l l l
••
V
PORT
VPORT
R
CLASS
AUX
R
CLASS
++
SW
VCC
V
CC
V
IN
V
CC
0.1µF
10µFBAV19WS
(T
RR
≤50ns)
22µF
HS
GATE
HS
SRC
FFS
DLY
PG
SG
ITHB
TO MICROPROCESSOR
ISEN
+
ISEN
–
4276 TA01
GND FB31 ROSC T2PSS
100µH
AUX
37V-57V
+
–
–
+
FMMT723
20mΩ
5V
13A
+
–
3.3k
10k
0.1µF
100pF
10nF
100k
LT4276A
OPTO
+
LT4276
2
4276fa
For more information www.linear.com/LT4276
pin conFiguraTionabsoluTe MaxiMuM raTings
VPORT, HSSRC, V
IN
Voltages .....................–0.3 to 100V
HSGATE Current.................................................. ±20mA
V
CC
Voltage .................................................... –0.3 to 8V
RCLASS, RCLASS
++
Voltages .................................–0.3 to 8V (and ≤ VPORT)
SFST, FFSDLY, ITHB, T2P Voltages ......–0.3 to V
CC
+0.3V
ISEN
+
, ISEN
–
Voltages ...........................................±0.3V
FB31 Voltage ..................................................+12V/–30V
RCLASS/RCLASS
++
Current .............................. –50mA
AUX Current ........................................................ ±1.4mA
ROSC Current .....................................................±100µA
RLDCMP Current ................................................±500µA
T2P Current .........................................................–2.5mA
Operating Junction Temperature Range (Note 3)
LT4276AI/LT4276BI/LT4276CI ..............–40°C to 85°C
LT4276AH/LT4276BH/LT4276CH ....... –40°C to 125°C
Storage Temperature Range .................. –65°C to 150°C
(Notes 1, 2)
9 10
TOP VIEW
UFD PACKAGE
28-LEAD (4mm × 5mm) PLASTIC QFN
11 12 13
28 27 26 25 24
14
23
6
5
4
3
2
1
GND
AUX
RCLASS
++
/NC*
RCLASS
T2P/NC**
V
CC
V
CC
V
CC
DNC
V
CC
PG
GND
SG
ISEN
+
ISEN
–
RLDCMP
VPORT
NC
HSGATE
HSSRC
V
IN
SWVCC
V
CC
ROSC
SFST
FFSDLY
ITHB
FB31
7
17
18
19
20
21
22
16
8
15
29
GND
T
JMAX
= 150°C, θ
JC
= 3.4°C/W
EXPOSED PAD (PIN 29) IS GND, MUST BE SOLDERED TO PCB
*RCLASS
++
is not connected in the LT4276B and LT4276C
**T2P is not connected in the LT4276C
orDer inForMaTion
LEAD FREE FINISH TAPE AND REEL PART MARKING* MAX PD POWER PACKAGE DESCRIPTION TEMPERATURE RANGE
LT4276AIUFD#PBF LT4276AIUFD#TRPBF 4276A 90W 28-Lead (4mm × 5mm) Plastic QFN –40°C to 85°C
LT4276AHUFD#PBF LT4276AHUFD#TRPBF 4276A 90W 28-Lead (4mm × 5mm) Plastic QFN –40°C to 125°C
LT4276BIUFD#PBF LT4276BIUFD#TRPBF 4276B 25.5W 28-Lead (4mm × 5mm) Plastic QFN –40°C to 85°C
LT4276BHUFD#PBF LT4276BHUFD#TRPBF 4276B 25.5W 28-Lead (4mm × 5mm) Plastic QFN –40°C to 125°C
LT4276CIUFD#PBF LT4276CIUFD#TRPBF 4276C 13W 28-Lead (4mm × 5mm) Plastic QFN –40°C to 85°C
LT4276CHUFD#PBF LT4276CHUFD#TRPBF 4276C 13W 28-Lead (4mm × 5mm) Plastic QFN –40°C to 125°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/. Some packages are available in 500 unit reels through
designated sales channels with #TRMPBF suffix.
LT4276
3
4276fa
For more information www.linear.com/LT4276
elecTrical characTerisTics
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VPORT, HSSRC, V
IN
Operating Voltage At VPORT Pin
l
60 V
V
SIG
VPORT Signature Range At VPORT Pin
l
1.5 10 V
V
CLASS
VPORT Classification Range At VPORT Pin
l
12.5 21 V
V
MARK
VPORT Mark Range At VPORT Pin, After 1st Classification Event
l
5.6 10 V
VPORT AUX Range At VPORT Pin, V
AUX
≥ 6.45V
l
8 60 V
Signature/Class Hysteresis Window
l
1.0 V
Reset Threshold
l
2.6 5.6 V
V
HSON
Hot Swap Turn-On Voltage
l
35 37 V
V
HSOFF
Hot Swap Turn-Off Voltage
l
30 31 V
Hot Swap On/Off Hysteresis Window
l
3 V
Supply Current
VPORT, HSSRC & V
IN
Supply Current V
VPORT
= V
HSSRC
= V
VIN
= 60V
l
2 mA
VPORT Supply Current During Classification V
VPORT
= 17.5V, RCLASS, RCLASS
++
Open
l
0.7 1.0 1.3 mA
VPORT Supply Current During Mark Event V
VPORT
= V
MARK
after 1st Classification Event
l
0.4 2.2 mA
Signature and Classification
Signature Resistance V
SIG
(Note 4)
l
23.6 24.4 25.5 kΩ
Signature Resistance During Mark Event V
MARK
(Note 4)
l
5.2 8.3 11.4 kΩ
RCLASS/RCLASS
++
Voltage –10mA ≥ I
RCLASS
≥ –36mA
l
1.36 1.40 1.43 V
Classification Stability Time V
VPORT
Step to 17.5V, R
CLS
= 35.7Ω
l
2 ms
Digital Interface
V
AUXT
AUX Threshold V
PORT
= 17.5V, V
IN
= V
HSSRC
= 18.5V
l
6.05 6.25 6.45 V
I
AUXH
AUX Pin Current V
AUX
= 6.05V, V
PORT
= 17.5V, V
IN
= 9V, V
CC
= 0V
l
3.3 5.3 7.3 µA
T2P Output High V
VCC
- V
T2P
, –1mA Load
l
0.3 V
T2P Leakage V
T2P
= 0V
l
–1 1 µA
Hot Swap Control
I
GPU
HSGATE Pull Up Current V
HSGATE
- V
HSSRC
= 5V (Note 5)
l
–27 –22 –18 µA
HSGATE Voltage –10µA Load, with respect to HSSRC
l
10 14 V
HSGATE Pull Down Current V
HSGATE
- V
HSSRC
= 5V
l
400 µA
V
CC
Supply
VCCREG V
CC
Regulation Voltage
l
7.2 7.6 8.0 V
Feedback Amplifier
V
FB
FB31 Regulation Voltage
l
3.11 3.17 3.23 V
FB31 Pin Bias Current RLDCMP Open -0.1 µA
gm Feedback Amplifier Average Trans-
Conductance
Time Average, –2µA < I
ITHB
< 2µA
l
–52 –40 –26 µA/V
I
SINK
ITHB Average Sink Current Time Average, V
FB31
= 0V
l
4.4 8.0 13.4 µA
Soft-Start
I
SFST
Charging Current V
SFST
= 0.5V, 3.0V
l
–49 –42 –36 µA
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
J
= 25°C. V
VPORT
= V
HSSRC
= V
VIN
= 40V, V
VCC
= VCCREG, ROSC, PG, and SG Open,
R
FFSDLY
= 5.23kΩ to GND. AUX connected to GND unless otherwise specified. (Note 2)
P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P21P22-P24P25-P26

LT4276BHUFD#PBF

Mfr. #:
Buy LT4276BHUFD#PBF
Manufacturer:
Analog Devices Inc.
Description:
Power Switch ICs - POE / LAN PoE+ PD with Forward/Flyback Controller
Lifecycle:
New from this manufacturer.
Delivery:
DHL FedEx Ups TNT EMS
Payment:
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