LTC3637_15,LTC3637_15 pdf中文资料,LTC3637_15引脚图,LTC3637

LTC3637

76V, 1A Step-Down

Regulator

FEATURES

n

DESCRIPTION

The

LTC

®

3637

is a high efficiency step-down DC/DC

regulator with an internal high side power switch that

draws only 12μA DC supply current while maintaining a

regulated output voltage at no load.

The LTC3637 can supply up to 1A load current and features

a programmable peak current limit that provides a simple

method for optimizing efficiency and for reducing output

ripple and component size. The LTC3637’s combination

of Burst Mode

®

operation, integrated power switch, low

quiescent current, and programmable peak current limit

provides high efficiency over a broad range of load currents.

With its wide input range of 4V to 76V, and programmable

overvoltage lockout, the LTC3637 is a robust regulator

suited for regulating from a wide variety of power sources.

Additionally, the LTC3637 includes a precise run threshold

and soft-start feature to guarantee that the power system

start-up is well-controlled in any environment.

The LTC3637 is available in the thermally-enhanced

3mm

×

5mm DFN and the MSE16 packages.

L,

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

of Linear Technology Corporation. All other trademarks are the property of their respective

owners.

Wide Operating Input Voltage Range: 4V to 76V

Internal 350mΩ Power MOSFET

No Compensation Required

Adjustable 100mA to 1A Maximum Output Current

Low Dropout Operation: 100% Duty Cycle

Low Quiescent Current: 12µA

Wide Output Range: 0.8V to V

IN

0.8V ±1% Feedback Voltage Reference

Precise RUN Pin Threshold

Internal and External Soft-Start

Programmable 1.8V, 3.3V, 5V or Adjustable Output

Few External Components Required

Programmable Input Overvoltage Lockout

Low Profile (0.75mm) 3mm

×

5mm DFN and

Thermally-Enhanced MSE16 Packages

APPLICATIONS

n

Industrial Control Supplies

Medical Devices

Distributed Power Systems

Portable Instruments

Battery-Operated Devices

Automotive

Avionics

TYPICAL APPLICATION

12.5V to 76V Input to 12V Output, 1A Regulator

V

IN

12.5V TO 76V

10µH

V

IN

2.2µF

SW

200k

47µF

V

OUT

12V

1A

Efficiency and Power Loss vs Load Current

100

90

80

EFFICIENCY (%)

70

60

50

40

30

20

10

3637 TA01a

V

OUT

= 12V

EFFICIENCY

POWER LOSS (mW)

LTC3637

RUN

FBO

V

FB

SS

V

PRG1

V

PRG2

I

SET

OVLO

GND

1000

35.7k

POWER LOSS

100

0

0.1

V

IN

= 24V 10

V

IN

= 48V

V

IN

= 76V

0

10

100

1000

1.0

LOAD CURRENT (mA)

3637 TA01b

3637fa

For more information

www.linear.com/LTC3637

1

LTC3637

ABSOLUTE MAXIMUM RATINGS

(Note 1)

V

IN

Supply Voltage ..................................... –0.3V to 80V

RUN Voltage............................................... –0.3V to 80V

SS, FBO, I

SET

Voltages ................................. –0.3V to 6V

V

FB

, V

PRG1

, V

PRG2

, OVLO Voltages .............. –0.3V to 6V

Operating Junction Temperature Range (Notes 2, 3, 4)

LTC3637E, LTC3637I ......................... –40°C to 125°C

LTC3637H .......................................... –40°C to 150°C

LTC3637MP ....................................... –55°C to 150°C

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

Lead Temperature (Soldering, 10 sec)

MSOP ............................................................... 300°C

PIN CONFIGURATION

TOP VIEW

SW 1

V

IN

3

FBO

V

PRG2

V

PRG1

GND

5

6

7

8

17

GND

16 GND

14 RUN

12

11

10

9

OVLO

I

SET

SS

V

FB

SW

NC

V

IN

NC

FBO

V

PRG2

V

PRG1

GND

1

2

3

4

5

6

7

8

17

GND

16 GND

15 NC

14 RUN

13 NC

12 OVLO

11 I

SET

10 SS

9

V

FB

MSE PACKAGE

VARIATION: MSE16 (12)

16-LEAD PLASTIC MSOP

T

JMAX

= 150°C,

θ

JA

= 45°C/W,

θ

JC

= 10°C/W

EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB

DHC PACKAGE

16-LEAD (5mm

×

3mm) PLASTIC DFN

(NOTE 6)

T

JMAX

= 150°C,

θ

JA

= 43°C/W,

θ

JC

= 5°C/W

EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB

ORDER INFORMATION

LEAD FREE FINISH

LTC3637EMSE#PBF

LTC3637IMSE#PBF

LTC3637HMSE#PBF

LTC3637MPMSE#PBF

LTC3637EDHC#PBF

LTC3637IDHC#PBF

LTC3637HDHC#PBF

LTC3637MPDHC#PBF

TAPE AND REEL

LTC3637EMSE#TRPBF

LTC3637IMSE#TRPBF

LTC3637HMSE#TRPBF

LTC3637MPMSE#TRPBF

LTC3637EDHC#TRPBF

LTC3637IDHC#TRPBF

LTC3637HDHC#TRPBF

LTC3637MPDHC#TRPBF

PART MARKING*

3637

PACKAGE DESCRIPTION

16-Lead Plastic MSOP

16-Lead (5mm

×

3mm) Plastic DFN

16-Lead (5mm

×

3mm) Plastic DFN

16-Lead (5mm

×

3mm) Plastic DFN

16-Lead (5mm

×

3mm) Plastic DFN

TEMPERATURE RANGE

–40°C to 125°C

–40°C to 150°C

–55°C to 150°C

–40°C to 125°C

–40°C to 150°C

–55°C to 150°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/

2

3637fa

For more information

www.linear.com/LTC3637

LTC3637

ELECTRICAL CHARACTERISTICS

SYMBOL

V

IN

V

OUT

UVLO

PARAMETER

Input Voltage Operating Range

Output Voltage Operating Range

V

IN

Undervoltage Lockout

DC Supply Current (Note 5)

Active Mode

Sleep Mode

Shutdown Mode

RUN and OVLO Pin Threshold Voltage

V

IN

Rising

V

IN

Falling

Hysteresis

l

The

l

denotes the specifications which apply over the specified operating

junction temperature range, otherwise specifications are at T

A

= 25°C (Note 2). V

IN

= 12V, unless otherwise noted.

CONDITIONS

MIN

4

0.8

3.45

3.30

3.65

3.5

150

165

12

3

1.17

1.06

–10

1.21

1.10

110

0

TYP

MAX

76

V

IN

3.85

3.70

UNITS

V

mV

µA

V

mV

nA

Input Supply (V

IN

)

I

Q

No Load

RUN = 0V

Rising

Falling

Hysteresis

RUN = 1.3V

V

FB

Rising, V

PRG1

= V

PRG2

= 0V

LTC3637E, LTC3637I

LTC3637H, LTC3637MP

V

FB

Falling, V

PRG1

= V

PRG2

= 0V

V

FB

= 1V, V

PRG1

= 0V, V

PRG2

= 0V

V

FB

Rising, V

PRG1

= SS, V

PRG2

= 0V

V

FB

Falling, V

PRG1

= SS, V

PRG2

= 0V

V

FB

Rising, V

PRG1

= 0V, V

PRG2

= SS

V

FB

Falling, V

PRG1

= 0V, V

PRG2

= SS

V

FB

Rising, V

PRG1

= V

PRG2

= SS

V

FB

Falling, V

PRG1

= V

PRG2

= SS

l

350

20

10

1.25

1.14

10

RUN Pin Leakage Current

Output Supply (V

FB

)

Feedback Comparator Threshold Voltage

(Adjustable Output)

Feedback Comparator Hysteresis

(Adjustable Output)

Feedback Pin Current

Feedback Comparator Threshold Voltages

(Fixed Output)

l

0.792

0.788

2.5

–10

4.940

4.910

3.250

3.230

1.775

1.765

0.800

5

0

5.015

4.985

3.310

3.290

1.805

1.795

0.001

0.808

0.812

7

10

5.090

5.060

3.370

3.350

1.835

1.825

V

mV

nA

V

%/V

Feedback Voltage Line Regulation

Operation

Peak Current Comparator Threshold

V

IN

= 4V to 76V

I

SET

Floating

100k Resistor from I

SET

to GND

I

SET

Shorted to GND

I

SW

= –200mA

V

IN

= 65V, SW = 0V

SS Pin < 2.5V

SS Pin Floating

3

l

2

0.9

0.17

2.4

1.2

0.24

0.35

0.1

5

0.8

2.8

1.5

0.31

1

6

A

Ω

μA

ms

Power Switch On-Resistance

Switch Pin Leakage Current

Soft-Start Pin Pull-Up Current

Internal Soft-Start Time

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:

The LTC3637 is tested under pulsed load conditions such that

T

J

≈ T

A

. The LTC3637E is guaranteed to meet performance specifications

from 0°C to 85°C. Specifications over the –40°C to 125°C operating

junction temperature range are assured by design, characterization and

correlation with statistical process controls. The LTC3637I is guaranteed

over the –40°C to 125°C operating junction temperature range, the

LTC3637H is guaranteed over the –40°C to 150°C operating junction

temperature range and the LTC3637MP is tested and guaranteed over the

–55°C to 150°C operating junction temperature range.

High junction temperatures degrade operating lifetimes; operating lifetime

is derated for junction temperatures greater than 125°C. Note that the

maximum ambient temperature consistent with these specifications is

determined by specific operating conditions in conjunction with board

layout, the rated package thermal impedance and other environmental

factors.

Note 3:

The junction temperature (T

J

, in °C) is calculated from the ambient

temperature (T

A

, in °C) and power dissipation (P

D

, in Watts) according to

the formula:

T

J

= T

A

+ (P

D

•

θ

JA

)

where

θ

JA

is 43°C/W for the DFN or 45°C/W for the MSOP

.

3637fa

For more information

www.linear.com/LTC3637

3

LTC3637

ELECTRICAL CHARACTERISTICS

Note that the maximum ambient temperature consistent with these

specifications is determined by specific operating conditions in

conjunction with board layout, the rated package thermal impedance and

other environmental factors.

Note 4:

This IC includes over temperature protection that is intended to

protect the device during momentary overload conditions. The maximum

rated junction temperature will be exceeded when this protection is active.

Continuous operation above the specified absolute maximum operating

junction temperature may impair device reliability or permanently damage

the device. The overtemperature protection level is not production tested.

Note 5:

Dynamic supply current is higher due to the gate charge being

delivered at the switching frequency. See Applications Information.

Note 6:

For application concerned with pin creepage and clearance

distances at high voltages, the MSOP package should be used. See

Applications Information.

TYPICAL PERFORMANCE CHARACTERISTICS

Efficiency and Power Loss

vs Load Current, V

OUT

= 5V

100

90

80

EFFICIENCY (%)

70

60

50

40

30

20

10

0

0.1

V

IN

= 12V 10

V

IN

= 24V

V

IN

= 70V

0

1.0

10

100

1000

LOAD CURRENT (mA)

3637 G01

Efficiency and Power Loss

vs Load Current, V

OUT

= 3.3V

100

V

OUT

= 3.3V

90 FIGURE 13 CIRCUIT

80

EFFICIENCY (%)

70

60

50

40

30

20

10

0

0.1

V

IN

= 12V 10

V

IN

= 24V

V

IN

= 68V

0

1.0

10

100

1000

LOAD CURRENT (mA)

3637 G02

Efficiency and Power Loss

vs Load Current, V

OUT

= 1.8V

100

V

OUT

= 1.8V

90 FIGURE 13 CIRCUIT

80

70

60

50

40

30

20

10

0

0.1

POWER LOSS

100

1000

POWER LOSS (mW)

1000

EFFICIENCY

POWER LOSS (mW)

V

OUT

= 5V, FIGURE 13 CIRCUIT

EFFICIENCY

1000

POWER LOSS

POWER LOSS (mW)

POWER LOSS

100

V

IN

= 12V 10

V

IN

= 24V

V

IN

= 67V

0

10

100

1000

1.0

LOAD CURRENT (mA)

3637 G03

Efficiency vs Input Voltage

100

V

OUT

= 5V

FIGURE 13 CIRCUIT

0.05

0.04

0.03

∆V

OUT

/V

OUT

(%/V)

0.02

0.01

0

–0.01

–0.02

–0.03

–0.04

70

80

–0.05

Line Regulation vs Input Voltage

V

OUT

= 5V

I

LOAD

= 1A

FIGURE 13 CIRCUIT

OUTPUT VOLTAGE (V)

5.02

Load Regulation vs Load Current

V

IN

= 12V

V

OUT

= 5V

FIGURE 13 CIRCUIT

90

EFFICIENCY (%)

5.01

80

5.00

70

I

LOAD

= 1A

I

LOAD

= 100mA

I

LOAD

= 10mA

I

LOAD

= 1mA

0

10

20

30 40

50 60

INPUT VOLTAGE (V)

60

4.99

50

5

15

45

35

25

55

INPUT VOLTAGE (V)

65

75

4.98

0 100 200 300 400 500 600 700 800 900 1000

LOAD CURRENT (mA)

3637 G06

3637 G04

3637 G05

4

3637fa

For more information

www.linear.com/LTC3637

LTC3637

TYPICAL PERFORMANCE CHARACTERISTICS

Feedback Comparator Trip

Voltage vs Temperature

FEEDBACK COMPARATOR TRIP VOLTAGE (V)

FEEDBACK COMPARATOR HYSTERESIS (mV)

0.804

V

IN

= 12V

5.5

5.4

5.3

5.2

5.1

5.0

4.9

4.8

4.7

4.6

4.5

–55

–25

65

35

5

95

TEMPERATURE (°C)

125

155

Feedback Comparator Hysteresis

vs Temperature

V

IN

= 12V

RUN AND OVLO COMPARATOR THRESHOLD (V)

1.24

1.22

1.20

1.18

1.16

1.14

1.12

1.10

1.08

RUN and OVLO Comparator

Threshold Voltages vs Temperature

RISING

0.802

0.800

0.798

FALLING

0.796

–55

–25

95

5

35

65

TEMPERATURE (°C)

125

155

1.06

–55

–25

5

35

65

95

TEMPERATURE (°C)

125

155

3637 G07

3637 G08

3637 G09

Peak Current Trip Threshold

vs R

ISET

2800

PEAK CURRENT TRIP THRESHOLD (mA)

2400

2000

1600

1200

800

400

0

50

100

150

R

ISET

(k )

200

250

3637 G10

Peak Current Trip Threshold

vs Temperature

2800

PEAK CURRENT TRIP THRESHOLD (mA)

Peak Current Trip Threshold

vs Input Voltage

2800

PEAK CURRENT TRIP THRESHOLD (mA)

2400

2000

1600

1200

800

400

0

ISET = 0V

0

10

20 30 40 50 60

INPUT VOLTAGE (V)

70

3637 G12

V

IN

= 12V

V

IN

= 12V

2400

2000

1600

1200

800

400

0

–55

–25

ISET OPEN

R

ISET

= 100k

R

ISET

= 100k

ISET = GND

95

5

65

35

TEMPERATURE (°C)

125

155

3637 G11

Quiescent V

IN

Supply Current

vs Input Voltage

20

30

25

20

15

10

5

Quiescent V

IN

Supply Current

vs Temperature

V

IN

= 12V

3.70

UVLO Threshold Voltages

vs Temperature

RISING

V

IN

SUPPLY CURRENT (µA)

V

IN

SUPPLY CURRENT (µA)

16

SLEEP

3.65

UVLO THRESHOLD (V)

12

3.60

SLEEP

8

SHUTDOWN

4

3.55

FALLING

SHUTDOWN

3.50

0

5

15

45

35

25

55

INPUT VOLTAGE (V)

65

75

0

–55 –25

65

35

95

5

TEMPERATURE (°C)

125

155

3.45

–55

–25

65

35

5

95

TEMPERATURE (°C)

125

155

3637 G13

3637 G14

3637 G15

3637fa

For more information

www.linear.com/LTC3637

5

LTC3637_15

LTC3637_15概述

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