LTC4292/LTC4291
1
Rev 0
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n PoE PSE Switches/Routers
n PoE PSE Midspans
APPLICATIONS
FEATURES DESCRIPTION
4-Port IEEE 802.3bt
PoE PSE Controller
The LTC
®
4292/LTC4291 chipset is a 4-port power sourc-
ing equipment (PSE) controller designed for use in IEEE
802.3bt Type 3 and 4 compliant Power over Ethernet
(PoE) systems. The LTC4292/LTC4291 is designed to
power compliant 802.3af, 802.3at, and 802.3bt PDs.
The LTC4292/LTC4291 chipset delivers lowest-in-indus-
try heat dissipation by utilizing low-RDS(ON) external
MOSFETs and 0.15Ω sense resistance per power channel.
Atransformer-isolated communication protocol replaces
expensive opto-couplers and complex isolated 3.3V sup-
ply, resulting in significant BOM cost savings.
Advanced power management features include per-
port 14-bit current monitoring, programmable current
limit, and versatile fast shut-down of preselected ports.
Advanced power management host software is available
under a no-cost license. PD detection uses a proprietary
multipoint detection mechanism ensuring excellent immu-
nity from false PD identification. Autoclass and 5-event
physical classification are supported. The LTC4292/
LTC4291 includes an I2C serial interface operable up to
1MHz. The LTC4292/LTC4291 is pin or I2C programmable
to negotiate PD delivered power up to 71.3W.
n Four PSE Ports
n Two Power Channels Per Port
n Fully Compliant IEEE 802.3bt Type 3 and 4 PSE
n Compliant Support for Type 1, 2, 3, and 4 PDs
n Low Power Path Dissipation per Channel
n 150mΩ Sense Resistance
n 30mΩ or Lower MOSFET RDS(ON)
n Chipset Provides Electrical Isolation
n Eliminates Optos and Isolated 3.3V Supply
n Very High Reliability Multipoint PD Detection
n Connection Check Distinguishes Single-
Signature and Dual-Signature PDs
n Continuous, Dedicated Per-Port Power and Current
Monitoring
n Per-Port Power Policing
n 1MHz I2C Compatible Serial Control Interface
n Pin or I2C Programmable PD Power Up to 71.3W
n Available in a 40-Lead 6mm × 6mm (LTC4292) and
24-Lead 4mm × 4mm (LTC4291) QFN Package
All registered trademarks and trademarks are the property of their respective owners.
TYPICAL APPLICATION
VSSKn
VSSKn
V
EE
V
EE
100Ω
100Ω
100Ω
100Ω
100Ω
100Ω
100Ω
100Ω
S1B
10Ω
0.15Ω
0.22µF
100V
S1B
S1B
0.15Ω
0.22µF
100V
S1B
2nF
0.1µF
1µF
100V
0.1µF
1µF
3.3V
V
EE
3.3V
CPA
CNA
DPA
DNA
V
EE
VSSKn
SENSEnA
GATEnA
AGNDP
LTC4292
1000BASE-T
V
EE
OUTnA
AGNDP
SENSEnB
GATEnB
OUTnB
AGNDP
TX1
TX2
TX3
TX4
RJ45
1
2
6
4
3
5
7
8
PWRMD0
PWRMD1
V
EE
MSD
SCL
SDAIN
AD0
DPD
CND
V
DD
LTC4291
CPD
DND
GP0
GP1
ISOLATION
AD1
AD2
AD3
SDAOUT
4PVALID
RESET
INT
AUTO
CAP1
3.3V
(NO I
2
C
ISOLATION
REQUIRED)
V
EE
AGNDP
(1 OF 4 PORTS)
CAP2
2kV
VSSKn
AGNDP
0.22μF, 100V
0.15Ω
429291
TA01a
LTC4292/LTC4291
2
Rev 0
For more information www.analog.com
PIN CONFIGURATION
ABSOLUTE MAXIMUM RATINGS
LTC4292
Supply Voltages
AGNDP – VEE ......................................... –0.3V to 80V
VSSK12, VSSK34 (Note 7) ... VEE – 0.3V to VEE + 0.3V
Digital Pins
PWRMD0, PWRMD1 ........ VEE – 0.3V to CAP2 + 0.3V
Analog Pins
SENSEnM, GATEnM, OUTnM VEE – 0.3V to VEE + 80V
CAP2 (Note 13) ...................... VEE – 0.3V to VEE + 5V
CPA, CNA, DPA, DNA .............. VEE – 0.3V to VEE + 0.3
Operating Ambient Temperature Range
LTC4292I .............................................–40°C to 85°C
Junction Temperature (Note 2) ............................ 125°C
Storage Temperature Range .................. –65°C to 150°C
(Notes 1, 4)
LTC4291
Supply Voltages
VDD – DGND ......................................... –0.3V to 3.6V
Digital Pins
SCL, SDAIN, SDAOUT, INT, RESET, MSD, ADn, AUTO,
4PVALID, GPn .................DGND – 0.3V to VDD + 0.3V
Analog Pins
CAP1 (Note 13) ...........................–0.3V to DGND + 2V
CPD, CND, DPD, DND ......DGND – 0.3V to VDD + 0.3V
Operating Ambient Temperature Range
LTC4291I .............................................–40°C to 85°C
Junction Temperature (Note 2) ............................ 125°C
Storage Temperature Range .................. –65°C to 150°C
(Note 1)
LTC4292 LTC4291
1211 13 14 15
TOP VIEW
41
VEE
UJ PACKAGE
40-LEAD (6mm × 6mm) PLASTIC QFN
TJMAX = 125°C, θJC = 2°C/W, θJA = 33°C/W
EXPOSED PAD (PIN 41) IS V
EE
, MUST BE SOLDERED TO PCB
16 17 18 19 20
3940 38 37 36 35 34 33 32 31
23
24
25
26
27
28
29
30
8
7
6
5
4
3
2
1GATE1A
OUT1A
GATE1B
OUT1B
VSSK12
CAP2
GATE2A
OUT2A
GATE2B
OUT2B
GATE4B
OUT4B
GATE4A
OUT4A
VSSK34
AGNDP
GATE3B
OUT3B
GATE3A
OUT3A
VEE
CPA
CNA
DPA
DNA
NC
NC
VEE
NC
VEE
PWRMD0
SENSE1A
SENSE1B
SENSE2A
SENSE2B
SENSE3A
SENSE3B
SENSE4A
SENSE4B
PWRMD1
22
21
9
10
24 23 22 21 20 19
789
TOP VIEW
UF PACKAGE
24-LEAD (4mm × 4mm) PLASTIC QFN
TJMAX = 125°C, θJC = 4°C/W, θJA = 47°C/W
EXPOSED PAD (PIN 25) IS DGND, MUST BE SOLDERED TO PCB
10 11 12
6
5
4
3
2
1
13
14
15
16
17
18
AD0
AD1
AD2
AD3
DGND
4PVALID
SCL
SDAIN
SDAOUT
INT
RESET
DNC
MSD
GP0
GP1
AUTO
VDD
CAP1
NC
CPD
CND
DPD
DND
VDD
25
DGND
LTC4292/LTC4291
3
Rev 0
For more information www.analog.com
ORDER INFORMATION
LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE
LTC4291IUF#PBF LTC4291IUF#TRPBF 4291 24-Lead (4mm × 4mm) Plastic QFN –40°C to 85°C
LTC4292IUJ#PBF LTC4292IUJ#TRPBF LTC4292UJ 40-Lead (6mm × 6mm) Plastic QFN –40°C to 85°C
Consult ADI Marketing for parts specified with wider operating temperature ranges.
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.
http://www.linear.com/product/LTC4292#orderinfo
LTC4292/LTC4291
4
Rev 0
For more information www.analog.com
D16832-0-4/18(0)
www.analog.com
ANALOG DEVICES, INC. 2018
RELATED PARTS
PART NUMBER DESCRIPTION COMMENTS
LT4294 LTPoE++/PoE+/PoE PD Controller External Switch, IEEE 802.3bt Support Configurable Class
LT4295 IEEE 802.3bt PD with Forward/Flyback
Switching Regulator Controller
External Switch, IEEE 802.3bt Support, Configurable Class, Forward or No-Opto Flyback
Operation, Frequency, PG/SG Delays, Soft-Start, and Aux Support as Low as 9V, Including
Housekeeping Buck, Slope Compensation
LTC4257-1 IEEE 802.3af PD Interface Controller Internal 100V, 400mA Switch, Dual Current Limit, Programmable Class
LTC4263 Single IEEE 802.3af PSE Controller Internal FET Switch
LTC4265 IEEE 802.3at PD Interface Controller Internal 100V, 1A Switch, 2-Event Classification Recognition
LTC4266 Quad IEEE 802.3at PoE PSE Controller With Programmable ICUT/ILIM, 2-Event Classification, and Port Current and Voltage Monitoring
LTC4267 IEEE 802.3af PD Interface with Integrated
Switching Regulator
Internal 100V, 400mA Switch, Dual Inrush Current, Programmable Class
LTC4269-1 IEEE 802.3at PD Interface with Integrated
Flyback Switching Regulator
2-Event Classification, Programmable Class, Synchronous No-Opto Flyback Controller,
50kHz to 250kHz, Aux Support
LTC4269-2 IEEE 802.3at PD Interface with Integrated
Forward Switching Regulator
2-Event Classification, Programmable Class, Synchronous Forward Controller, 100kHz to
500kHz, Aux Support
LTC4270/
LTC4271
12-Port PoE/PoE+/LTPoE++
®
PSE Controller Transformer Isolation, Supports Type 1, Type 2 and LTPoE++ PDs
LTC4278 IEEE 802.3at PD Interface with Integrated
Flyback Switching Regulator
2-Event Classification, Programmable Class, Synchronous No-Opto Flyback Controller,
50kHz to 250kHz, 12V Aux Support
LTC4279 Single PoE/PoE+/LTPoE++ PSE Controller Supports IEEE 802.3af, IEEE 802.3at, LTPoE++ and Proprietary PDs
LTC4290/
LTC4271
8-Port PoE/PoE+/LTPoE++ PSE Controller Transformer Isolation, Supports IEEE 802.3af, IEEE 802.3at and LTPoE++ PDs
TYPICAL APPLICATION
VSSKn
VSSKn
V
EE
V
EE
100Ω
100Ω
100Ω
100Ω
100Ω
100Ω
100Ω
100Ω
S1B
10Ω
0.15Ω
>47µF
0.22µF
100V
S1B
S1B
0.15Ω
0.22µF
100V
S1B
2nF
0.1µF
1µF
100V
0.1µF
1µF
3.3V
V
EE
3.3V
CPA
CNA
DPA
DNA
V
EE
VSSKn
SENSEnA
GATEnA
AGNDP
LTC4292
1000BASE-T
V
EE
OUTnA
AGNDP
SENSEnB
GATEnB
OUTnB
AGNDP
TX1
TX2
TX3
TX4
RJ45
1
2
6
4
3
5
7
8
PWRMD0
PWRMD1
V
EE
MSD
SCL
SDAIN
AD0
DGND
DPD
CND
V
DD
LTC4291
CPD
DND
GP0
GP1
ISOLATION
AD1
AD2
AD3
SDAOUT
4PVALID
RESET
INT
AUTO
CAP1
3.3V
(NO I
2
C
ISOLATION
REQUIRED)
V
EE
AGNDP
(1 OF 4 PORTS)
D1
D2
QnA, QnB: PSMN040-100MSE
D1: SMCJ58A
D2: SMAJ58A
CAP2
2kV
QnA
QnB
VSSKn
AGNDP
0.22μF, 100V
0.15Ω
429291 F34
Figure 34. IEEE 802.3bt Type 3 or Type 4 PSE, Alternative A (MDI-X) and Alternative B(S), 1000BASE-T, 1 of 4 Ports Shown