LT4275AIDD#PBF datasheet, PDF - EEWORLD Datasheet

FeaTures

n

LT4275

LTPoE++/PoE+/PoE

PD Controller

DescripTion

The LT

®

4275 is a pin-for-pin compatible family of IEEE

802.3 and LTPoE++ powered device (PD) controllers.

The LT4275A employs a proprietary LTPoE++ classification

scheme, delivering 38.7W, 52.7W, 70W or 90W of power

at the PD RJ45 connector. The LT4275A is fully compat-

ible with IEEE 802.3. The LT4275B is an IEEE 802.3at

compliant, Type 2 (PoE+) PD delivering up to 25.5W. The

LT4275C is an IEEE 802.3af compliant, Type 1 (PoE) PD

delivering up to 13W.

The LT4275 internal charge pump provides an N-channel

MOSFET solution, eliminating a larger and more costly

P-channel MOSFET. A low R

DS(ON)

MOSFET also maxi-

mizes power delivery and efficiency, reduces power and

heat dissipation, and eases thermal design. Startup inrush

current is adjustable with an external capacitor. The LT4275

also includes a power good output, on-board signature

resistor, undervoltage lockout, and thermal protection. The

LT4275A/LT4275B drives a single opto-coupler to indicate

the power level of the attached PSE. Pin-selectable sup-

port for non-standard low voltage operation is provided.

Auxiliary power override is supported with the AUX pin.

The LT4275A can be configured to support all possible

LTPoE++, 802.3at and 802.3af power levels with external

component changes.

L,

LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and

LTPoE++ and Hot Swap are trademarks of Linear Technology Corporation. All other trademarks

are the property of their respective owners.

n

IEEE 802.3af/at and LTPoE++™ Powered Device

(PD) Controller

LTPoE++ Supports Power Levels Up to 90W

LT4275A 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

LT4275B is IEEE 802.3at/af Compliant

LT4275C is IEEE 802.3af Compliant

100V Absolute Maximum Input Voltage

Wide Junction Temperature Range (–40°C to 125°C)

Overtemperature Protection

Integrated Signature Resistor

External Hot Swap™ N-Channel MOSFET for Lowest

Power Dissipation and Highest System Efficiency

Programmable Aux Power Support as Low as 9V

Optional Support of Non-Standard Low Voltage PoE

Available in 10-Lead MSOP and 3mm

×

3mm DFN

Packages

applicaTions

n

High Power Wireless Data Systems

Outdoor Security Camera Equipment

Commercial and Public Information Displays

High Temperature Industrial Applications

Typical applicaTion

LTPoE++ 90W Powered Device Interface

V

AUX

(9V TO 60V)

FDMC86102

V

PORT

C

PD

0.1µF

3.3k

47nF

VPORT HSGATE

AUX

RCLASS

RCLASS++

R

CLS

R

CLS++

LT4275A

T2P

4275 TA01a

+

LT4275 Family

C

PORT

DATA

PAIR

~

+

–

+

–

V

IN

ISOLATED

POWER

SUPPLY

RUN

MAX DELIVERED

POWER

LTPoE++ 90W

+

V

OUT

LT4275 GRADE

A

l

B

C

SPARE

PAIR

HSSRC

PWRGD

LTPoE++ 70W

LTPoE++ 52.7W

LTPoE++ 38.7W

25.5W

13W

–

GND

IEEEUVLO

OPTO

PSE TYPE

(TO µP)

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LT4275

absoluTe MaxiMuM raTings

(Notes 1, 3)

VPORT, HSSRC Voltages ......................... –0.3V to 100V

HSGATE Current.................................................. ±20mA

IEEEUVLO,

RCLASS,

RCLASS++ Voltages ....... –0.3V to 8V (and ≤ VPORT)

AUX Current ........................................................ ±1.4mA

T2P,

PWRGD Voltage ............................... –0.3V to 100V

T2P,

PWRGD Current ...............................................5mA

Operating Junction Temperature Range (Note 4)

LT4275AI/LT4275BI/LT4275CI..............–40°C to 85°C

LT4275AH/LT4275BH/LT4275CH ....... –40°C to 125°C

Storage Temperature Range .................. –65°C to 150°C

Lead Temperature (Soldering, 10 sec.).................. 300°C

pin conFiguraTion

TOP VIEW

IEEEUVLO

AUX

RCLASS

RCLASS++/NC*

GND

1

2

3

4

5

11

GND

10 VPORT

9 HSGATE

8 HSSRC

7 PWRGD

6

T2P/NC*

IEEEUVLO

AUX

RCLASS

RCLASS++/NC*

GND

1

2

3

4

5

TOP VIEW

10

9

8

7

6

VPORT

HSGATE

HSSRC

PWRGD

T2P/NC*

DD PACKAGE

10-LEAD (3mm

×

3mm) PLASTIC DFN

T

JMAX

= 150°C,

θ

JC

= 5°C/W

EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB GND

MS PACKAGE

10-LEAD PLASTIC MSOP

T

JMAX

= 150°C,

θ

JC

= 45°C/W

* RCLASS++ is not connected in the LT4275B/C versions.

T2P

is not connected in the LT4275C version.

orDer inForMaTion

LEAD FREE FINISH

LT4275AIDD#PBF

LT4275AHDD#PBF

LT4275AIMS#PBF

LT4275AHMS#PBF

LT4275BIDD#PBF

LT4275BHDD#PBF

LT4275BIMS#PBF

LT4275BHMS#PBF

LT4275CIDD#PBF

LT4275CHDD#PBF

LT4275CIMS#PBF

LT4275CHMS#PBF

TAPE AND REEL

LT4275AIDD#TRPBF

LT4275AHDD#TRPBF

LT4275AIMS#TRPBF

LT4275AHMS#TRPBF

LT4275BIDD#TRPBF

LT4275BHDD#TRPBF

LT4275BIMS#TRPBF

LT4275BHMS#TRPBF

LT4275CIDD#TRPBF

LT4275CHDD#TRPBF

LT4275CIMS#TRPBF

LT4275CHMS#TRPBF

PART MARKING*

LGBS

LTGBT

LGBV

LTGBW

LGBX

LTGBY

MAX PD

POWER

90W

25.5W

13W

PACKAGE DESCRIPTION

10-Lead (3mm

×

3mm) Plastic DFN

10-Lead (3mm

×

3mm) Plastic DFN

10-Lead Plastic MSOP

10-Lead (3mm

×

3mm) Plastic DFN

10-Lead (3mm

×

3mm) Plastic DFN

10-Lead Plastic MSOP

10-Lead (3mm

×

3mm) Plastic DFN

10-Lead (3mm

×

3mm) Plastic DFN

10-Lead Plastic MSOP

TEMPERATURE RANGE

–40°C to 85°C

–40°C to 125°C

–40°C to 85°C

–40°C to 125°C

–40°C to 85°C

–40°C to 125°C

–40°C to 85°C

–40°C to 125°C

–40°C to 85°C

–40°C to 125°C

–40°C to 85°C

–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.

Consult LTC Marketing for information on nonstandard lead based finish parts.

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/

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LT4275

The

l

denotes the specifications which apply over the full operating

temperature range, otherwise specifications are at T

A

= 25°C. (Note 3)

SYMBOL

V

SIG

V

CLASS

V

MARK

PARAMETER

VPORT Operating Input Voltage

VPORT Signature Range

VPORT Classification Range

VPORT Mark Range

VPORT Aux Mode Range

Signature/Class Hysteresis Window

V

RESET

V

HSON

V

HSOFF

Reset Threshold

Hot Swap Turn-On Voltage

Hot Swap Turn-Off Voltage

Hot Swap On/Off Hysteresis Window

Supply Current

Supply Current During Classification

Supply Current During Mark Event

Signature and Classification

Signature Resistance

V

RCLS

V

SIG

(Note 2)

l

elecTrical characTerisTics

CONDITIONS

At VPORT Pin

At VPORT Pin, Preceded by V

CLASS

At VPORT Pin, AUX > V

AUXT

l

MIN

23

1.5

12.5

5.6

8

1.0

2.6

TYP

MAX

60

10

21

10

60

5.6

UNITS

V

IEEEUVLO

= 0V

IEEEUVLO

Open

IEEEUVLO

= 0V

IEEEUVLO

Open

l

35

27

30

21.5

3

31

22.5

37

29

VPORT = HSSRC = 57V

VPORT = 17.5V, RCLASS and RCLASS++ Open

V

MARK

l

2

0.4

0.5

23.7

5.8

1.32

24.4

8.3

1.40

0.7

1.1

2.2

25.2

11

1.43

2

6.1

4

6.3

5.8

6.5

8

0.8

5

18

10

200

690

840

990

22

27

18

mA

kΩ

V

ms

V

µA

V

µA

V

µA

Hz

Signature Resistance During Mark Event V

MARK

(Note 2)

RCLASS/RCLASS++ Operating Voltage

–10mA ≥ I

RCLASS

≥ –36mA, V

CLASS

Classification Stability Time

VPORT Step to 17.5V, RCLASS = 34.8Ω

AUX Threshold

AUX Pin Hysteresis Current

T2P

Output Low

PWRGD Output Low

PWRGD Leakage Current

T2P

Leakage Current

AUX = 6.1V

1mA Load (LT4275A/LT4275B Only)

1mA Load

PWRGD = 60V

T2P

= 60V

V

HSGATE

– V

HSSRC

= 5V, V

PORT

> 42V, Out of Pin

V

HSGATE

– V

HSSRC

, 0µA to 10µA Load with Respect

to HSSRC

V

HSGATE

– V

HSSRC

= 5V

After PWRGD Valid, if LTPoE++ PSE Is Mutually

Identified

Analog/Digital Interface

V

AUXT

I

AUXH

l

Hot Swap Control

I

GPU

V

GOC

HSGATE Pull-Up Current

HSGATE Open Circuit Voltage

HSGATE Pull-Down Current

Timing

f

T2P

Frequency

l

Note 1:

Stresses beyond those listed under Absolute Maximum Ratings

may cause permanent damage to the device. Exposure to any Absolute

Maximum Rating condition for extended periods may affect device

reliability and lifetime.

Note 2:

Signature resistance specifications do not include resistance

added by the external diode bridge which can add as much as 1.1k to the

port resistance.

Note 3:

All voltages with respect to GND unless otherwise noted. Positive

currents are into pins; negative currents are out of pins unless otherwise

noted.

Note 4:

This IC includes overtemperature protection that is intended

to protect the device during momentary overload conditions. Junction

temperature will exceed 150°C when overtemperature protection is active.

Continuous operation above the specified maximum operating junction

temperature may impair device reliability.

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LT4275

Typical perForMance characTerisTics

VPORT Current vs VPORT Voltage

25k Detection Range

0.5

T = –40°C

T = 25°C

T = 75°C

T = 125°C

VPORT VOLTAGE (V)

37

36

35

34

33

32

31

0

2

4

6

VPORT VOLTAGE (V)

8

10

4275 G01

VPORT Hot Swap Thresholds

IEEEUVLO

= 0V

Hot Swap ON

SUPPLY CURRENT (mA)

1.5

2.0

Supply Current During Power-On

T = –40°C

T = 25°C

T = 75°C

T = 125°C

0.4

VPORT CURRENT (mA)

0.3

1.0

0.2

0.1

0.5

Hot Swap OFF

0

30

–50

–25

0

25

50

75

TEMPERATURE (°C)

100

125

35

40

45

50

VPORT VOLTAGE (V)

55

60

4275 G03

4275 G02

Signature Resistance

vs Input Voltage

26.25

T = –40°C

T = 25°C

T = 75°C

T = 125°C

VPORT VOLTAGE (V)

29.0

VPORT Hot Swap Thresholds

IEEEUVLO

= FLOAT

Hot Swap ON

VPORT VOLTAGE (V)

Hot Swap OFF

–25

0

25

50

75

TEMPERATURE (°C)

100

125

5.6

5.1

4.6

4.1

3.6

3.1

Reset Threshold

SIGNATURE RESISTANCE (k )

25.75

27.5

25.25

26.0

24.75

24.5

24.25

23.0

23.75

1

3

5

7

VPORT VOLTAGE (V)

9

4275 G04

21.5

–50

2.6

–50

–25

0

25

50

75

TEMPERATURE (°C)

100

125

4275 G05

4275 G06

PWRGD,

T2P

Output Low

Voltage vs Current

4

T = –40°C

T = 25°C

T = 75°C

T = 125°C

VPORT VOLTAGE (V)

12.5

VPORT Classification Thresholds

DETECT OR MARK TO CLASS

CLASS TO MARK

T2P

FREQUENCY (Hz)

990

940

890

840

790

740

T2P

Frequency

3

VOLTAGE (V)

12.0

11.5

2

11.0

1

10.5

0

1

2

3

CURRENT (mA)

4

5

4275 G07

10.0

–50

–25

0

25

50

75

TEMPERATURE (°C)

100

125

690

–50

–25

0

25

50

75

TEMPERATURE (°C)

100

125

4275 G08

4275 G09

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LT4275

pin FuncTions

IEEEUVLO

(Pin 1):

Hot Swap Turn-on Threshold Level

Control. Connect to ground for IEEE compliant turn-on

and turn-off (UVLO) voltage thresholds. Leave open for

lower turn-on and turn-off voltage thresholds.

AUX (Pin 2):

Auxiliary Sense. Assert AUX via a resistive

divider from the auxiliary power input to set the voltage

at which the auxiliary supply takes over. Asserting AUX

pulls down HSGATE, disconnects the signature resistor,

disables classification and floats the PWRGD pin. The

AUX pin sinks I

AUXH

when below its threshold voltage of

V

AUXT

to provide hysteresis. Tie to GND when not used.

RCLASS (Pin 3):

Programmable PoE Classification Resis-

tor. See Table 1.

RCLASS++ (Pin 4, LT4275A Only):

Programmable

LTPoE++ Classification Resistor. This pin is not connected

on the LT4275B/LT4275C. See Table 1.

GND (Pin 5):

Ground Pin. Must be soldered to PCB GND.

T2P

(Pin 6, LT4275A/LT4275B Only):

PSE Type Indica-

tor, Open-Drain Output.

T2P

floats for a 13W PSE.

T2P

pulls down for a 25.5W PSE.

T2P

pulls down at f

T2P

with

a 50% (typical) duty cycle to indicate the presence of an

LTPoE++ PSE.

T2P

is valid after PWRGD is active. This pin

is not connected on the LT4275C. See the Applications

Information section for behavior when using the AUX pin.

PWRGD (Pin 7):

Power Good Indicator, Open-Drain Output.

Pulls down during V

CLASS

and inrush.

HSSRC (Pin 8):

External Hot Swap MOSFET Source. Con-

nect to source of the external MOSFET.

HSGATE (Pin 9):

External Hot Swap MOSFET Gate Control,

Output. Connect to gate of the external MOSFET.

VPORT (Pin 10):

PD interface upper power rail and external

Hot Swap MOSFET drain connection.

Exposed Pad (Pin 11, DFN Package Only):

GND. Must

be soldered to PCB GND.

block DiagraM

V

PORT

VPORT

VOLTAGE AND

CURRENT REFERENCES

PWRGD

IEEEUVLO

CONTROL

LOGIC

ON

HSGATE

CHARGE

PUMP

V

GOC

HSSRC

AUX

6.3V

+

–

OVERTEMP

T2P

V

PORT

1.4V

+

EN

–

CLASSIFICATION

LOGIC

V

PORT

EN

+

–

1.4V

RCLASS++

RCLASS

GND

4275 BD

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Parameter Name	Attribute value
EU restricts the use of certain hazardous substances	Compliant
ECCN (US)	EAR99
Part Status	Active
HTS	8542.39.00.01
Standard Supported	IEEE802.3af/IEEE802.3at
Minimum Input Voltage (V)	23
Maximum Input Voltage (V)	60
Maximum Output Power (W)	90
Maximum Duty Cycle (%)	50(Typ)
Programmability	Yes
Minimum Operating Temperature (°C)	-40
Maximum Operating Temperature (°C)	85
Packaging	Tube
Pin Count	10
Standard Package Name	DFN
Supplier Package	DFN EP
Mounting	Surface Mount
Package Height	0.75(Max)
Package Length	3
Package Width	3
PCB changed	10
Lead Shape	No Lead

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