LTC3407AIMSE-2-TR,LTC3407AIMSE-2-TR pdf中文资料,LTC3407AIMSE-2-TR引脚图,LTC3407AIMSE-2-TR电路-Datasheet-电子工程世界

LTC3407A-2

Dual Synchronous 800mA,

2.25MHz Step-Down

DC/DC Regulator

FEATURES

■

DESCRIPTIO

High Efficiency: Up to 95%

Low Ripple (<35mV

PK-PK

) Burst Mode Operation;

I

Q

= 40μA

2.25MHz Constant Frequency Operation

No Schottky Diodes Required

Low R

DS(ON)

Internal Switches: 0.35Ω

Current Mode Operation for Excellent Line

and Load Transient Response

Short-Circuit Protected

Low Dropout Operation: 100% Duty Cycle

Ultralow Shutdown Current: I

Q

<1μA

Output Voltages from 5V down to 0.6V

Power-On Reset Output

Externally Synchronizable Oscillator

Optional External Soft-Start

Small Thermally Enhanced MSOP and 3mm

×

3mm

DFN Packages

The LTC

®

3407A-2 is a dual, constant frequency, synchro-

nous step-down DC/DC converter. Intended for low power

applications, it operates from a 2.5V to 5.5V input voltage

range and has a constant 2.25MHz switching frequency,

enabling the use of tiny, low cost capacitors and inductors

1mm or less in height. Each output voltage is adjustable

from 0.6V to 5V. Internal synchronous 0.35Ω, 1A power

switches provide high efficiency without the need for

external Schottky diodes.

A user selectable mode input is provided to allow the user

to trade-off ripple noise for low power efficiency. Burst

Mode

®

operation provides the highest efficiency at light

loads, while Pulse Skip Mode provides the lowest ripple

noise at light loads.

To further maximize battery life, the P-channel MOSFETs

are turned on continuously in dropout (100% duty cycle),

and both channels draw a total quiescent current of only

40μA. In shutdown, the device draws <1μA.

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

Corporation. All other trademarks are the property of their respective owners. Protected by

U.S. Patents including 5481178, 6580258, 6304066, 6127815, 6498466, 6611131.

APPLICATIO S

■

PDAs/Palmtop PCs

Digital Cameras

Cellular Phones

Wireless and DSL Modems

TYPICAL APPLICATIO

V

IN

= 2.5V

TO 5.5V

10μF

1mm High 2.5V/1.8V at 800mA Step-Down Regulators

100

90

RUN/SS2

MODE/SYNC

LTC3407A-2

V

OUT2

= 2.5V

AT 800mA

2.2μH

SW2

22pF

SW1

22pF

2.2μH

V

OUT1

= 1.8V

AT 800mA

V

IN

RUN/SS1

POR

100k

RESET

EFFICIENCY (%)

887k

10μF

280k

V

FB2

GND

V

FB1

887k

442k

10μF

3407A2 TA01

U

Efficiency/Power Loss Curve

1

2.5V

1.8V

0.1

80

70

60

50

40

30

20

10

0

1

10

100

LOAD CURRENT (mA)

V

IN

= 3.3V

Burst Mode OPERATION

NO LOAD ON OTHER CHANNEL

0.0001

1000

3407A2 TA02

U

POWER LOSS (W)

0.01

0.001

3407a2f

1

LTC3407A-2

ABSOLUTE

(Note 1)

AXI U RATI GS

Operating Temperature Range (Note 2)

LTC3407AE-2 ..................................... – 40°C to 85°C

LTC3407AI-2 .................................... – 40°C to 125°C

Junction Temperature (Note 5) ............................. 125°C

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

Lead Temperature (Soldering, 10 sec)

LTC3407AEMSE-2 ............................................ 300°C

LTC3407AIMSE-2 ............................................. 300°C

V

IN

Voltage ..................................................– 0.3V to 6V

V

FB1

, V

FB2

Voltages...................................– 0.3V to 1.5V

RUN/SS1, RUN/SS2 Voltages ..................... – 0.3V to V

IN

MODE/SYNC Voltage .................................. – 0.3V to V

IN

SW1, SW2 Voltages ....................... – 0.3V to V

IN

+ 0.3V

POR Voltage ................................................– 0.3V to 6V

PI CO FIGURATIO

TOP VIEW

V

FB1

RUN/SS1

V

IN

SW1

GND

1

2

3

4

5

11

10

V

FB2

9

RUN/SS2

8

POR

7

SW2

6

MODE/SYNC

DD PACKAGE

10-LEAD (3mm

×

3mm) PLASTIC DFN

T

JMAX

= 125°C,

θ

JA

= 45°C/W,

θ

JC

= 10°C/W

EXPOSED PAD (PIN 11) IS PGND, MUST BE CONNECTED TO GND

ORDER I FOR ATIO

LEAD FREE FINISH

LTC3407AEDD-2#PBF

LTC3407AEMSE-2#PBF

LTC3407AIDD-2#PBF

LTC3407AIMSE-2#PBF

LEAD BASED FINISH

LTC3407AEDD-2

LTC3407AEMSE-2

LTC3407AIDD-2

LTC3407AIMSE-2

TAPE AND REEL

LTC3407AEDD-2#TRPBF

LTC3407AEMSE-2#TRPBF

LTC3407AIDD-2#TRPBF

LTC3407AIMSE-2#TRPBF

TAPE AND REEL

LTC3407AEDD-2#TR

LTC3407AEMSE-2#TR

LTC3407AIDD-2#TR

LTC3407AIMSE-2#TR

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/

2

U

W W

U

W

U

TOP VIEW

V

FB1

RUN/SS1

V

IN

SW1

GND

1

2

3

4

5

10

9

8

7

6

V

FB2

RUN/SS2

POR

SW2

MODE/SYNC

11

MSE PACKAGE

10-LEAD PLASTIC MSOP

T

JMAX

= 125°C,

θ

JA

= 45°C/W,

θ

JC

= 10°C/W

EXPOSED PAD (PIN 11) IS PGND, MUST BE CONNECTED TO GND

PART MARKING*

LDDH

LTDDJ

LDDH

LTDDJ

PART MARKING*

LDDH

LTDDJ

LDDH

LTDDJ

PACKAGE DESCRIPTION

10-Lead (3mm

×

3mm) Plastic DFN

10-Lead Plastic MSOP

10-Lead (3mm

×

3mm) Plastic DFN

10-Lead Plastic MSOP

PACKAGE DESCRIPTION

10-Lead (3mm

×

3mm) Plastic DFN

10-Lead Plastic MSOP

10-Lead (3mm

×

3mm) Plastic DFN

10-Lead Plastic MSOP

TEMPERATURE RANGE

–40°C to 85°C

–40°C to 125°C

TEMPERATURE RANGE

–40°C to 85°C

–40°C to 125°C

3407a2f

LTC3407A-2

The

●

denotes the specifications which apply over the full operating

temperature range, otherwise specifications are at T

A

= 25°C. V

IN

= 3.6V, unless otherwise specified. (Note 2)

SYMBOL

V

IN

I

FB

V

FB

ΔV

LINE REG

ΔV

LOAD REG

I

S

PARAMETER

Operating Voltage Range

Feedback Pin Input Current

Feedback Voltage (Note 3)

Reference Voltage Line Regulation

Output Voltage Load Regulation

Input DC Supply Current

Active Mode

Sleep Mode

Shutdown

Oscillator Frequency

Synchronization Frequency

Peak Switch Current Limit

Top Switch On-Resistance

Bottom Switch On-Resistance

Switch Leakage Current

Power-On Reset Threshold

Power-On Reset On-Resistance

Power-On Reset Delay

V

RUN

I

RUN

V

MODE

RUN/SS Threshold Low

RUN/SS Threshold High

RUN/SS Leakage Current

MODE Threshold Low

MODE Threshold High

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 LTC3407AE-2 is guaranteed to meet specified performance

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

temperature range are assured by design, characterization and correlation

with statistical process controls. The LTC3407AI-2 is guaranteed over the

full –40°C to 125°C operating temperature range.

●

ELECTRICAL CHARACTERISTICS

CONDITIONS

●

MIN

2.5

0.588

0.585

TYP

MAX

5.5

30

UNITS

V

nA

V

%/V

%

0°C

≤

T

A

≤

85°C

–40°C

≤

T

A

≤

125°C (Note 2)

V

IN

= 2.5V to 5.5V (Note 3)

MODE/SYNC = 0V (Note 3)

(Note 4)

V

FB1

= V

FB2

= 0.5V

V

FB1

= V

FB2

= 0.63V, MODE/SYNC = 3.6V

RUN = 0V, V

IN

= 5.5V, MODE/SYNC = 0V

V

FBX

= 0.6V

V

IN

= 3V, V

FBX

= 0.5V, Duty Cycle <35%

(Note 6)

V

IN

= 5V, V

RUN

= 0V, V

FBX

= 0V

V

FBX

Ramping Up, MODE/SYNC = 0V

V

FBX

Ramping Down, MODE/SYNC = 0V

●

0.6

0.3

0.5

700

40

0.1

0.612

0.5

950

60

1

2.7

1.6

0.45

1

μA

MHz

A

Ω

μA

%

f

OSC

f

SYNC

I

LIM

R

DS(ON)

I

SW(LKG)

POR

●

1.8

1

2.25

1.2

0.35

0.30

0.01

8.5

–8.5

100

65,536

200

1.5

2

1

0.5

V

IN

Ω

Cycles

V

μA

V

0.3

1

0.01

0

V

IN

– 0.5

Note 3:

The LTC3407A-2 is tested in a proprietary test mode that connects

V

FB

to the output of the error amplifier.

Note 4:

Dynamic supply current is higher due to the internal gate charge

being delivered at the switching frequency.

Note 5:

T

J

is calculated from the ambient T

A

and power dissipation P

D

according to the following formula: T

J

= T

A

+ (P

D

•

θ

JA

).

Note 6:

The DFN switch on-resistance is guaranteed by correlation to

wafer level measurements.

3407a2f

3

LTC3407A-2

TYPICAL PERFOR A CE CHARACTERISTICS

Burst Mode Operation

SW

5V/DIV

V

OUT

50mV/DIV

I

L

200mA/DIV

V

IN

= 3.6V

V

OUT

= 1.8V

I

LOAD

= 50mA

CIRCUIT OF FIGURE 3

Load Step

V

OUT1

200mV/DIV

V

OUT2

100mV/DIV

I

L

500mA/DIV

V

IN

2V/DIV

I

LOAD

500mA/DIV

V

IN

= 3.6V

V

OUT

= 1.8V

I

LOAD

= 50mA TO 600mA

CIRCUIT OF FIGURE 3

Efficiency vs Input Voltage

100

90

80

1mA

10mA

100mA

800mA

60

50

40

30

20

10 V

OUT

= 1.8V

CIRCUIT OF FIGURE 3

0

4

3

2

5

INPUT VOLTAGE (V)

FREQUENCY (MHz)

EFFICIENCY (%)

70

FREQUENCY DEVIATION (%)

4

U W

2μs/DIV

20μs/DIV

6

3407A2 G04

T

A

= 25°C unless otherwise specified.

Pulse Skipping Mode

SW

5V/DIV

V

OUT

10mV/DIV

I

L

100mA/DIV

3407A2 G01

V

IN

= 3.6V

V

OUT

= 1.8V

I

LOAD

= 50mA

CIRCUIT OF FIGURE 3

1μs/DIV

3407A2 G02

Soft Start

V

OUT1

1V/DIV

I

L

500mA/DIV

V

IN

= 3.6V

V

OUT

= 1.8V

I

LOAD

= 500mA

CIRCUIT OF FIGURE 4

3407A2 G03

1ms/DIV

3407A2 G16

Oscillator Frequency vs

Temperature

2.5

V

IN

= 3.6V

10

8

6

4

2

0

–2

–4

–6

–8

2.0

–50 –25

–10

50

25

75

0

TEMPERATURE (°C)

100

125

Oscillator Frequency vs Supply

Voltage

2.4

2.3

2.2

2.1

2

3

4

SUPPLY VOLTAGE (V)

5

6

3407A2 G06

3407A2 G05

3407a2f

LTC3407A-2

TYPICAL PERFOR A CE CHARACTERISTICS

Reference Voltage vs

Temperature

0.615

V

IN

= 3.6V

0.610

450

R

DS(ON)

(mΩ)

REFERENCE VOLTAGE (V)

R

DS(ON)

(mΩ)

0.605

0.600

0.595

0.590

0.585

–50 –25

50

25

75

0

TEMPERATURE (°C)

Efficiency vs Load Current

100

90

80

70

EFFICIENCY (%)

60

50

40

30

20

10 V

OUT

= 2.5V Burst Mode OPERATION

CIRCUIT OF FIGURE 3

0

1

10

100

LOAD CURRENT (mA)

2.7V

4.2V

3.3V

100

90

80

V

OUT

ERROR(%)

Efficiency vs Load Current

100

90

80

70

EFFICIENCY (%)

60

50

40

30

20

10

0

1

V

OUT

= 1.2V Burst Mode OPERATION

10

100

LOAD CURRENT (mA)

1000

3407A2 G13

3.3V

2.7V

4.2V

EFFICIENCY (%)

60

50

40

30

20

10

0

1

V

OUT

= 1.5V Burst Mode OPERATION

10

100

LOAD CURRENT (mA)

1000

3407A2 G14

V

OUT

ERROR (%)

U W

100

3407A2 G07

3407A2 G10

T

A

= 25°C unless otherwise specified.

R

DS(ON)

vs Temperature

550

500

V

IN

= 4.2V

V

IN

= 2.7V

V

IN

= 3.6V

R

DS(ON)

vs Input Voltage

500

400

350

300

250

200

MAIN

SWITCH

400

350

300

250

200

150

MAIN SWITCH

SYNCHRONOUS SWITCH

0

25 50 75 100 125 150

TEMPERATURE (°C)

3407A2 G09

SYNCHRONOUS

SWITCH

125

1

2

3

4

V

IN

(V)

5

6

7

100

–50 –25

3407A2 G08

Efficiency vs Load Current

4

Burst Mode OPERATION

3

2

Load Regulation

70

60

50

40

30

20

10 V

IN

= 3.6V, V

OUT

= 1.8V

NO LOAD ON OTHER CHANNEL

0

1

10

100

LOAD CURRENT (mA)

PULSE SKIP MODE

1 Burst Mode OPERATION

0

–1

–2

–3

–4

1

V

IN

= 3.6V, V

OUT

= 1.8V

NO LOAD ON OTHER CHANNEL

10

100

LOAD CURRENT (mA)

1000

3407A2 G12

PULSE SKIP MODE

1000

3407A2 G11

Efficiency vs Load Current

100

90

80

70

4.2V

3.3V

2.7V

Line Regulation

0.5

0.4

0.3

0.2

0.1

0

–0.1

–0.2

–0.3

–0.4

–0.5

2

3

4

V

IN

(V)

5

6

3407A2 G15

V

OUT

= 1.8V

I

OUT

= 200mA

3407a2f

5

LTC3407AIMSE-2-TR

LTC3407AIMSE-2-TR概述

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