LTC4228-1/LTC4228-2

Dual Ideal Diode and

Hot Swap Controller

FeaTures

n

DescripTion

The LTC

®

4228 offers ideal diode and Hot Swap™ functions

for two power rails by controlling two external N-channel

MOSFETs in each rail. MOSFETs acting as ideal diodes re-

place two high power Schottky diodes and the associated

heat sinks, saving power and board area. Hot Swap control

MOSFETs allow boards to be safely inserted and removed

from a live backplane by limiting inrush current. The supply

output is also protected against short-circuit faults with a

fast acting current limit and internal timed circuit breaker.

The LTC4228 regulates the forward voltage drop across

the external MOSFETs and sense resistor to ensure smooth

current transfer from one supply to the other without

oscillation. The ideal diodes turn on quickly to reduce

the load voltage droop during supply switch-over. If the

input supply fails or is shorted, a fast turn-off minimizes

reverse-current transients.

The LTC4228 allows independent on/off control, and reports

fault and power good status for the supply. The LTC4228

improves on the LTC4225 by recovering more quickly from

input brownouts to preserve the output voltage.

L,

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

Technology Corporation. Hot Swap is a trademark of Linear Technology Corporation. All other

trademarks are the property of their respective owners.

Power Path and Inrush Current Control for

Redundant Supplies

Low Loss Replacement for Power Schottky Diodes

Protects Output Voltage from Input Brownouts

Allows Safe Hot Swapping from a Live Backplane

2.9V to 18V Operating Range

Controls N-Channel MOSFETs

Limits Peak Fault Current in ≤1µs

Adjustable Current Limit with Circuit Breaker

Adjustable Current Limit Fault Delay

Smooth Switchover without Oscillation

0.5µs Ideal Diode Turn-On and Turn-Off Time

Status, Fault and Power Good Outputs

LTC4228-1: Latch Off After Fault

LTC4228-2: Automatic Retry After Fault

28-Lead 4mm

×

5mm QFN and SSOP Packages

applicaTions

n

Redundant Power Supplies

MicroTCA Systems and Servers

Telecom Networks

Power Prioritizer

Typical applicaTion

µTCA Application

12V

0.1µF

Si7336ADP

0.004

Si7336ADP

PLUG-IN

CARD 1

12V

7.6A

Smooth Supply Switchover

CPO1

137k

ON1

20k

0.1µF

INTV

CC

GND

20k

ON2

137k

CPO2

IN1

DGATE1

SENSE1

+

SENSE1

–

HGATE1 OUT1

STATUS1

FAULT1

PWRGD1

EN1

LTC4228

TMR1

TMR2

EN2

PWRGD2

FAULT2

STATUS2

47nF

PLUG-IN

CARD 2

IN1

1V/DIV

IN2

1V/DIV

I

IN1

2A/DIV

I

IN2

2A/DIV

200ms/DIV

422512 TA01b

IN2

DGATE2

SENSE2

+

SENSE2

–

HGATE2 OUT2

0.1µF

12V

Si7336ADP

0.004

Si7336ADP

BACKPLANE

12V

7.6A

422812 TA01a

422812f

1

LTC4228-1/LTC4228-2

absoluTe MaxiMuM raTings

(Notes 1, 2)

Supply Voltages

IN1, IN2.................................................. –0.3V to 24V

INTV

CC

..................................................... –0.3V to 7V

Input Voltages

ON1, ON2,

EN1, EN2...............................

–0.3V to 24V

TMR1, TMR2 .........................–0.3V to INTV

CC

+ 0.3V

SENSE1

+

, SENSE2

+

................................ –0.3V to 24V

SENSE1

–

, SENSE2

–

................................ –0.3V to 24V

Output Voltages

FAULT1, FAULT2, PWRGD1, PWRGD2

..... –0.3V to 24V

STATUS1, STATUS2

................................ –0.3V to 24V

CPO1, CPO2 (Note 3) ............................. –0.3V to 35V

DGATE1, DGATE2 (Note 3) ..................... –0.3V to 35V

HGATE1, HGATE2 (Note 4) ..................... –0.3V to 35V

OUT1, OUT2 ........................................... –0.3V to 24V

Average Currents

FAULT1, FAULT2, PWRGD1, PWRGD2

...................5mA

STATUS1, STATUS2

..............................................5mA

INTV

CC

.................................................................1mA

Operating Temperature Range

LTC4228C ................................................ 0°C to 70°C

LTC4228I .............................................–40°C to 85°C

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

Lead Temperature (Soldering, 10 sec)

GN Package ...................................................... 300°C

pin conFiguraTion

STATUS1

TOP VIEW

PWRGD1

DGATE1

HGATE1

STATUS1

CPO1

DGATE1

22

FAULT1

21 ON1

20

EN1

29

19 TMR1

18 TMR2

17

EN2

16 ON2

15

FAULT2

9 10 11 12 13 14

CPO2

DGATE2

STATUS2

HGATE2

OUT2

PWRGD2

SENSE1

–

SENSE1

+

IN1

INTV

CC

GND

IN2

SENSE2

–

TOP VIEW

1

2

3

4

5

6

7

8

9

11

28 HGATE1

27 OUT1

26

PWRGD1

25

FAULT1

24 ON1

23

EN1

22 TMR1

21 TMR2

20

EN2

19 ON2

18

FAULT2

17

PWRGD2

16 OUT2

15 HGATE2

OUT1

28 27 26 25 24 23

SENSE1

–

1

SENSE1

+

2

IN1 3

INTV

CC

4

GND 5

IN2 6

SENSE2

+

7

SENSE2

–

8

CPO1

SENSE2

+

10

DGATE2 12

CPO2 13

STATUS2

14

UFD PACKAGE

28-LEAD (4mm

×

5mm) PLASTIC QFN

T

JMAX

= 125°C,

θ

JA

= 43°C/W (NOTE 5)

EXPOSED PAD (PIN 29) PCB GND CONNECTION OPTIONAL

GN PACKAGE

28-LEAD PLASTIC SSOP NARROW

T

JMAX

= 125°C,

θ

JA

= 80°C/W

422812f

2

LTC4228-1/LTC4228-2

orDer inForMaTion

LEAD FREE FINISH

LTC4228CUFD-1#PBF

LTC4228CUFD-2#PBF

LTC4228IUFD-1#PBF

LTC4228IUFD-2#PBF

LTC4228CGN-1#PBF

LTC4228CGN-2#PBF

LTC4228IGN-1#PBF

LTC4228IGN-2#PBF

TAPE AND REEL

LTC4228CUFD-1#TRPBF

LTC4228CUFD-2#TRPBF

LTC4228IUFD-1#TRPBF

LTC4228IUFD-2#TRPBF

LTC4228CGN-1#TRPBF

LTC4228CGN-2#TRPBF

LTC4228IGN-1#TRPBF

LTC4228IGN-2#TRPBF

PART MARKING*

42281

42282

42281

42282

LTC4228GN-1

LTC4228GN-2

LTC4228GN-1

LTC4228GN-2

PACKAGE DESCRIPTION

28-Lead (4mm

×

5mm) Plastic QFN

28-Lead (4mm

×

5mm) Plastic QFN

28-Lead (4mm

×

5mm) Plastic QFN

28-Lead (4mm

×

5mm) Plastic QFN

28-Lead Plastic SSOP

TEMPERATURE RANGE

0°C to 70°C

–40°C to 85°C

0°C to 70°C

–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.

Consult LTC Marketing for information on non-standard 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/

elecTrical characTerisTics

SYMBOL

Supplies

V

IN

I

IN

V

INTVCC

V

INTVCC(UVL)

Input Supply Range

Input Supply Current

Internal Regulator Voltage

Internal V

CC

Undervoltage Lockout

PARAMETER

The

l

denotes the specifications which apply over the full operating

temperature range, otherwise specifications are at T

A

= 25°C. V

IN

= 12V, unless otherwise noted.

CONDITIONS

l

MIN

2.9

TYP

MAX

18

UNITS

V

mA

V

mV

V

µA

A

2.5

4.5

2.1

30

10

5

10

0.3

–60

–50

5

2.2

60

25

7

12

0.7

–95

–85

–1.5

1.5

5

5.6

2.3

90

40

14

1.1

–120

–110

I = 0, –500µA

INTV

CC

Rising

l

∆V

INTVCC(HYST)

Internal V

CC

Undervoltage Lockout Hysteresis

Ideal Diode Control

∆V

FWD(REG)

∆V

DGATE

∆V

DGATE(ST)

I

CPO(UP)

I

DGATE(FPU)

I

DGATE(FPD)

t

ON(DGATE)

t

OFF(DGATE)

∆V

SENSE(CB)

∆V

SENSE(ACL)

V

SENSE+(UVL)

∆V

SENSE+(HYST)

I

SENSE+

I

SENSE–

∆V

HGATE

Forward Regulation Voltage (V

INn

– V

OUTn

)

External N-Channel Gate Drive

(V

DGATEn

– V

INn

)

Diode MOSFET On Detect Threshold

CPOn Pull-Up Current

DGATEn Fast Pull-Up Current

DGATEn Fast Pull-Down Current

DGATEn Turn-On Delay

DGATEn Turn-Off Delay

Circuit Breaker Trip Sense Voltage

(V

SENSEn+

– V

SENSEn–

)

Active Current Limit Sense Voltage

(V

SENSEn+

– V

SENSEn–

)

SENSEn

+

Undervoltage Lockout

SENSEn

+

Input Current

SENSEn

–

Input Current

External N-Channel Gate Drive

(V

HGATEn

– V

OUTn

)

SENSEn

+

Undervoltage Lockout Hysteresis

SENSE

+

= 12V

SENSE

–

= 12V

IN < 7V, I = 0, –1µA

IN = 7V to 18V, I = 0, –1µA

IN < 7V,

∆V

FWD

= 0.1V, I = 0, –1µA

IN = 7V to 18V,

∆V

FWD

= 0.1V, I = 0, –1µA

STATUS

Pulls Low,

∆V

FWD

= 50mV

CPO = IN = 2.9V

CPO = IN = 18V

∆V

FWD

= 0.2V,

∆V

DGATE

= 0V, CPO = 17V

∆V

FWD

= –0.2V,

∆V

DGATE

= 5V

∆V

FWD

= 0.2V, C

DGATE

= 10nF

∆V

FWD

= –0.2V, C

DGATE

= 10nF

l

0.25

0.2

47.5

55

1.75

10

150

10

4.8

10

50

65

1.9

50

350

50

7

12

0.5

52.5

75

2.05

90

500

100

14

µs

mV

V

mV

µA

V

422812f

Hot Swap Control

l

SENSE

+

Rising

l

3

LTC4228-1/LTC4228-2

elecTrical characTerisTics

SYMBOL

∆V

HGATE(PG)

I

HGATE(UP)

I

HGATE(DN)

I

HGATE(FPD)

t

PHL(SENSE)

t

OFF(HGATE)

t

D(HGATE)

t

P(HGATE)

Input/Output Pin

V

ON(TH)

∆V

ON(HYST)

V

ON(RESET)

I

ON(LEAK)

V

EN(TH)

∆V

EN(HYST)

I

EN(UP)

V

TMR(TH)

I

TMR(UP)

I

TMR(DN)

I

TMR(RATIO)

I

OUT

V

OL

V

OH

I

OH

I

PU

t

RST(ON)

ONn Threshold Voltage

ONn Hysteresis

ONn Fault Reset Threshold Voltage

ONn Input Leakage Current

ENn

Threshold Voltage

ENn

Hysteresis

ENn

Pull-Up Current

TMRn Threshold Voltage

TMRn Pull-Up Current

TMRn Pull-Down Current

TMRn Current Ratio I

TMR(DN)

/I

TMR(UP)

OUTn Current

Output Low Voltage

(FAULTn,

PWRGDn, STATUSn)

Output High Voltage

(FAULTn,

PWRGDn, STATUSn)

Input Leakage Current

(FAULTn,

PWRGDn, STATUSn)

Output Pull-Up Current

(FAULTn,

PWRGDn, STATUSn)

ONn Low to

FAULTn

High

OUT = 11V, IN = 12V, ON = 2V

OUT = 13V, IN = 12V, ON = 2V

I = 1mA

I = –1µA

V = 18V

V = 1.5V

EN

= 1V

TMR Rising

TMR Falling

TMR = 1V, In Fault Mode

TMR = 2V, No Faults

ON Falling

ON = 5V

EN

Rising

ON Rising

l

The

l

denotes the specifications which apply over the full operating

temperature range, otherwise specifications are at T

A

= 25°C. V

IN

= 12V, unless otherwise noted.

PARAMETER

Gate-Source Voltage for Power Good

External N-Channel Gate Pull-Up Current

External N-Channel Gate Pull-Down Current

External N-Channel Gate Fast

Pull-Down Current

Sense Voltage (SENSEn

+

– SENSEn

–

)

High to HGATEn Low

ENn

High to HGATEn Low

ONn Low to HGATEn Low

SENSEn

+

Low to HGATEn Low

ONn High,

ENn

Low to HGATEn

Turn-On Delay

ONn to HGATEn Propagation Delay

ON = Step 0.8V to 2V

Gate Drive On, HGATE = 0V

Gate Drive Off, OUT = 12V,

HGATE = OUT + 5V

Fast Turn-Off, OUT = 12V,

HGATE = OUT + 5V

∆V

SENSE

= 300mV, C

HGATE

= 10nF

CONDITIONS

l

MIN

3.6

–7

150

100

TYP

4.2

–10

300

200

0.5

20

10

MAX

4.8

–13

500

300

1

40

20

150

20

1.26

140

0.63

±1

1.284

200

–13

1.272

0.25

–125

2.6

2.7

120

5

0.4

UNITS

V

µA

mA

µs

ms

µs

V

mV

V

µA

V

mV

µA

V

µA

%

µA

mA

V

50

100

10

1.21

40

0.55

1.185

40

–7

1.198

0.15

–75

1.4

1.235

80

0.6

0

1.235

130

–10

1.235

0.2

–100

2

50

2.5

0.15

l

INTV

CC

– 1 INTV

CC

– 0.5

l

0

–7

–10

20

±1

–13

40

µA

µs

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:

All currents into device pins are positive; all currents out of device

pins are negative. All voltages are referenced to GND unless otherwise

specified.

Note 3:

An internal clamp limits the DGATE and CPO pins to a minimum of

10V above and a diode below IN. Driving these pins to voltages beyond the

clamp may damage the device.

Note 4:

An internal clamp limits the HGATE pin to a minimum of 10V

above and a diode below OUT. Driving this pin to voltages beyond the

clamp may damage the device.

Note 5:

Thermal resistance is specified when the exposed pad is soldered

to a 3" × 4.5", four layer, FR4 board.

422812f

4

LTC4228-1/LTC4228-2

Typical perForMance characTerisTics

T

A

= 25°C, V

IN

= 12V, unless otherwise noted.

IN Supply Current vs Voltage

4

6

5

3

4

INTV

CC

(V)

I

IN

(mA)

2

3

2

1

0

V

IN

= 3.3V

INTV

CC

Load Regulation

V

IN

= 12V

V

CPO

– V

IN

(∆V

CPO

) (V)

CPO Voltage vs Current

12

10

8

V

IN

= 18V

6

4

2

0

V

IN

= 2.9V

0

3

6

9

V

IN

(V)

12

15

18

0

–2

–4

–6

I

LOAD

(mA)

–8

–10

422812 G02

–2

0

–20

–40

–80

–60

I

CPO

(µA)

–100

–120

422812 G01

422812 G03

Diode Gate Voltage vs Current

12

10

V

DGATE

– V

IN

(∆V

DGATE

) (V)

GATE DRIVE (∆V

HGATE

) (V)

8

6

4

2

0

–2

0

–20

–40

–80

–60

I

DGATE

(µA)

–100

–120

V

IN

= 2.9V

V

IN

= 18V

V

OUT

= V

IN

– 0.1V

14

12

10

Hot Swap Gate Voltage vs Current

V

OUT

= V

IN

V

IN

= 12V

3.0

2.5

2.0

I

OUT

(mA)

1.5

1.0

0.5

0

–2

–4

–6

I

HGATE

(µA)

–8

–10

–12

–0.5

OUT Current vs Voltage

V

IN

= 12V

8

6

4

2

0

V

IN

= 2.9V

0

3

6

9

12

V

OUT

(V)

15

18

422812 G04

422812 G05

422812 G06

Circuit Breaker Trip Voltage

vs Temperature

ACTIVE CURRENT LIMIT SENSE VOLTAGE (mV)

52

CIRCUIT BREAKER TRIP VOLTAGE (mV)

67

Active Current Limit Sense

Voltage vs Temperature

100

ACTIVE CURRENT LIMIT DELAY (µs)

Active Current Limit Delay

vs Sense Voltage

C

HGATE

= 10nF

51

66

10

50

65

1

49

64

48

–50

–25

0

25

50

TEMPERATURE (°C)

75

100

63

–50

–25

0

25

50

TEMPERATURE (°C)

75

100

0.1

50

100

150

200

250

SENSE VOLTAGE (V

IN

– V

SENSE

) (mV)

300

422812 G07

422812 G08

422812 G09

422812f

5

参数名称	属性值
类型	热交换控制器，OR 控制器
通道数	2
内部开关	无
应用	通用
特性	自动重试，UVLO
可编程特性	限流，故障超时，压摆率
电压 - 电源	2.9 V ~ 18 V
工作温度	-40°C ~ 85°C
电流 - 电源	2.5mA
安装类型	表面贴装
封装/外壳	28-WFQFN 裸露焊盘
供应商器件封装	28-QFN（4x5）
功能引脚	CPO1，CPO2，/EN1，/EN2，/FAULT1，/FAULT2，IN1，IN2，INTVCC，ON1，ON2，OUT1，OUT2，/PWERGD1，/PWRGD2，TMR1，TMR2

LTC4228IUFD-2#TRPBF

LTC4228IUFD-2#TRPBF概述

LTC4228IUFD-2#TRPBF规格参数

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