LT3782IFE#PBF Datasheet LT3782EUFD#PBF, LT3782IFE#PBF, LT3782IFE#TRPBF | P1-P3

LT3782

1

3782fg

TYPICAL APPLICATION

FEATURES

APPLICATIONS

DESCRIPTION

2-Phase Step-UP

DC/DC Controller

The LT

®

3782 is a current mode two phase step-up DC/DC

converter controller. Its high switching frequency (up to

500kHz) and 2-phase operation reduce system ﬁ ltering

capacitance and inductance requirements.

With 10V gate drive (V

CC

≥13V) and 4A peak drive current,

the LT3782 can drive most industrial grade high power

MOSFETs with high efﬁ ciency. For synchronous applica-

tions, the LT3782 provides synchronous gate signals with

programmable falling edge delay to avoid cross conduc-

tion when using external MOSFET drivers. Other features

include programmable undervoltage lockout, soft-start,

current limit, duty cycle clamp (50% or higher) and slope

compensation.

The LT3782 is available in thermally enhanced 28-lead

TSSOP and 4mm × 5mm QFN packages.

For new designs use the LT3782A which has improved

phase matching

L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.

All other trademarks are the property of their respective owners.

Protected by U.S. Patents including 6144194.

n

Industrial Equipment

n

Telecom Infrastructure

n

Interleaved Isolated Power Supply

n

2-Phase Operation Reduces Required Input and

Output Capacitance

n

Programmable Switching Frequency:

150kHz to 500kHz

n

6V to 40V Input Range

n

10V Gate Drive with V

CC

≥13V

n

High Current Gate Drive (4A)

n

Programmable Soft-Start and Current Limit

n

Programmable Slope Compensation for

High Noise Immunity

n

MOSFET Gate Signals with Programmable

Falling Edge Delay for External Synchronous

Drivers

n

Programmable Undervoltage Lockout

n

Programmable Duty Cycle Clamp (50% or Higher)

n

Thermally Enhanced 28-Lead TSSOP and 4mm × 5mm

QFN Packages

50V 4A Boost Converter

3782 TA01

6.8nF

13k

0.1μF

10nF

C

IN

10μF

50V

2x

R

FREQ

80k

R

SLOPE

59k

R

S1

0.004Ω

M1

Si7852dp

2x

1μF

R8

274k

R6

825k

C

OUT2

220μF

V

OUT

50V, 4A

V

IN

10V TO 36V

+

C3

2μF

+

R

S2

0.004Ω

LT3782

V

CC

RUN

SLOPE

DELAY

DCL

R

SET

SS

V

C

GBIAS2

GBIAS

BGATE1

V

EE1

BGATE2

V

EE2

SENSE1

+

SENSE1

–

SENSE2

+

SENSE2

–

FB

GND

M2

Si7852dp

2x

GBIAS1

10Ω

10nF

10Ω

R

F1

475k

L1

D1

30BQ060

D2

30BQ060

L2

100pF

R

F2

24.9k

C

OUT1

10μF

50V

2x

L1, L2: PB2020.223

C

IN

, C

OUT1

: X7R, TDK

Efﬁ ciency and Power Loss

vs Load Current

I

OUT

(A)

0

EFFICIENCY (%)

4

3782 TA01b

POWER LOSS (W)

18

15

12

9

6

3

0

1

2

3

5

V

IN

= 12V

V

IN

= 12V

V

IN

= 24V

V

IN

= 24V

EFFICIENCY

POWER LOSS

97

93

95

91

89

87

85

NOT RECOMMENDED FOR NEW DESIGNS

Contact Linear Technology for Potential Replacement

LT3782

2

3782fg

T

JMAX

= 125°C, θ

JA

= 38°C/ W

EXPOSED PAD (PIN 29) IS GND, MUST BE SOLDERED TO PCB

V

CC

Supply Voltage ...................................................40V

GBIAS, GBIAS1, GBIAS2 Pin

(Externally Forced) ....................................................14V

SYNC, RUN Pin .........................................................30V

Operating Junction Temperature

Range (Notes 2, 3) ................................. –40°C to 125°C

(Note 1)

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

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

SS ................................................................ –0.3V to 6V

SENSE1

+

, SENSE2

+

,

SENSE1

–

, SENSE2

–

..................................... –0.3V to 2V

1

2

3

4

5

6

7

8

9

10

11

12

13

14

TOP VIEW

FE PACKAGE

28-LEAD PLASTIC TSSOP

28

27

26

25

24

23

22

21

20

19

18

17

16

15

SGATE2

SGATE1

NC

GND

SYNC

DELAY

DCL

SENSE1

+

SENSE1

–

SLOPE

R

SET

SENSE2

–

SENSE2

+

SS

GBIAS

V

CC

NC

V

EE1

BGATE1

GBIAS1

GBIAS2

BGATE2

V

EE2

NC

RUN

FB

V

C

29

9 10

TOP VIEW

29

UFD PACKAGE

28-LEAD (4mm × 5mm) PLASTIC QFN

11 12 13

28 27 26 25 24

14

23

6

5

4

3

2

1

SYNC

DELAY

DCL

SENSE1

+

SENSE1

–

SLOPE

R

SET

SENSE2

–

BGATE1

GBIAS1

NC

GBIAS2

BGATE2

V

EE2

NC

GND

SGATE1

SGATE2

GBIAS

V

CC

V

EE1

NC

SENSE2

+

SS

V

C

FB

RUN

7

17

18

19

20

21

22

16

8

15

T

JMAX

= 125°C, θ

JA

= 37°C/ W

EXPOSED PAD (PIN 29) IS GND, MUST BE SOLDERED TO PCB

ABSOLUTE MAXIMUM RATINGS

PIN CONFIGURATION

ORDER INFORMATION

LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE

LT3782EFE#PBF LT3782EFE#TRPBF LT3782EFE 28-Lead Plastic TSSOP –40°C to 85°C

LT3782IFE#PBF LT3782IFE#TRPBF LT3782IFE 28-Lead Plastic TSSOP –40°C to 125°C

LT3782EUFD#PBF LT3782EUFD#TRPBF 3782

28-Lead (4mm × 5mm) Plastic QFN

–40°C to 85°C

LEAD BASED FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE

LT3782EFE LT3782EFE#TR LT3782EFE 28-Lead Plastic SSOP –40°C to 85°C

LT3782IFE LT3782IFE#TR LT3782IFE 28-Lead Plastic SSOP –40°C to 125°C

LT3782EUFD LT3782EUFD#TR 3782

28-Lead (4mm × 5mm) Plastic QFN

–40°C to 85°C

Consult LTC Marketing for parts speciﬁ ed 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 speciﬁ cations, go to: http://www.linear.com/tapeandreel/

LT3782

3

3782fg

The ● denotes the speciﬁ cations which apply over the full operating junction

temperature range, otherwise speciﬁ cations are at T

A

= 25°C. V

CC

= 13V, R

SET

= 80k, no load on any outputs, unless otherwise noted.

PARAMETER CONDITIONS MIN TYP MAX UNITS

Overall

Supply Voltage (V

CC

)

l

640V

Supply Current (I

VCC

)V

C

≤ 0.5V (Switching Off), V

CC

≤ 40V 11 16 mA

Shutdown

RUN Threshold

l

2.3 2.45 2.6 V

RUN Threshold Hysteresis 80 mV

Supply Current in Shutdown 1V ≤ RUN ≤ V

REF

, V

CC

≤ 30V

RUN ≤ 0.3V, V

CC

≤ 30V

0.4

40

0.65

90

mA

μA

RUN Pin Input Current V

RUN

= 2.3V

l

–0.5 –2 μA

Voltage Ampliﬁ er g

m

Reference Voltage (V

REF

)

l

2.42

2.4

2.44 2.464

2.488

V

Transconductance V

VC

= 1V, ΔI

VC

= ±2μA

l

200 260 370 μmho

Input Current I

FB

V

FB

= V

REF

l

0.2 0.6 μA

V

C

High I

VC

= 0 1.5 V

V

C

Low I

VC

= 0 0.35 0.4 V

Source Current I

VC

V

VC

= 0.7V – 1V, V

FB

= V

REF

– 100mV 8 11 14 μA

Sink Current I

VC

V

VC

= 0.7V – 1V, V

FB

= V

REF

+ 100mV 13 20 28 μA

V

C

Threshold for Switching Off (BGATE1, BGATE2 Low)

l

0.3 V

Soft-Start Current I

SS

V

SS

= 0.1V – 2.8V 6 10 15 μA

Current Ampliﬁ er CA1, CA2

Voltage Gain ΔV

C

/ΔV

SENSE

4

Current Limit (V

SENSE1

+

– V

SENSE1

–

) (V

SENSE2

+

– V

SENSE2

–

) 506280 mV

Input Current (I

SENSE1

+

, I

SENSE1

–

, I

SENSE2

+

, I

SENSE2

–

)ΔV

SENSE

= 0V 60 μA

Oscillator

Switching Frequency R

SET

= 130k

R

SET

= 80k

R

SET

= 40k

l

130

212

386

154

250

465

177

288

533

kHz

Synchronization Pulse Threshold on SYNC Pin Rising Edge V

SYNC

0.8 1.2 2 V

Synchronization Frequency Range

(Note: Operation Switching Frequency Equals

Half of the Synchronization Frequency)

R

SET

= 130k

R

SET

= 80k

R

SET

= 40k

180

290

550

240

392

715

kHz

V

RSET

R

SET

= 80k 2.3 V

Maximum Duty Cycle V

FB

= V

REF

– 25mV, R

SET

> 80k

R

SET

= 40k

l

90

83

94

90

%

Duty Cycle Limit R

SET

= 80k, V

DCL

≤ 0.3V

V

DCL

= 1.2V

V

DCL

= V

RSET

50

75

Max Duty Cycle

%

DCL Pin Input Current V

DCL

≤ 0.3V

l

–0.1 –0.3 μA

ELECTRICAL CHARACTERISTICS

LT3782IFE#PBF

LT3782IFE#PBF

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