Linear Technology LT3759 Demo Manual

DESCRIPTION

DEMO MANUAL DC1787A

LT3759

Wide Input Voltage Range

Boost/SEPIC/Inverting Controller

Demonstration circuit 1787A is a wide input voltage range SEPIC converter featuring the LT3759 controller. It converts a 2.8V~36V input to a 12V output, with 1A load current capability for V

≥ 4V. The converter operates at

IN

a 300 kHz nominal switching frequency, with 91% peak efficiency. The DC1787A can be easily modified to generate other output voltages, and can also be optimized for efficiency and size with narrower input voltage ranges.

The LT3759 is a boost/SEPIC/Inverting controller with a wide input voltage range, suitable for applications from single-cell lithium-ion battery portable electronics to high voltage automotive and industrial power supplies. It also exhibits low shutdown quiescent current of 1A, making it an ideal fit for battery-operated systems. Thanks to a novel

PERFORMANCE SUMMARY

PARAMETER CONDITIONS MIN TYP MAX UNITS

Input Voltage Range, V

Minimum Startup Voltage 3.0 V

Switching Frequency I

Output Voltage, V

Maximum Continuous Output Current, I

Output Voltage Ripple (Peak-to-Peak) V

Typical Efficiency V

IN

V

OUT

(TA = 25°C)

= 0.5A 300 kHz

OUT

= 2.8V~36V

IN

I

= 0mA~0.5A

OUT

VIN ≥ 2.8V 0.5 A

≥ 4.0V 1 A

V

IN

= 12V, I

IN

= 12V, I

IN

FBX pin architecture, the LT3759 can be connected directly to a divider from either positive output or negative output voltage to ground. It also packs many popular features such as soft-start, input undervoltage lockout, adjustable frequency and synchronization in a small 12-lead exposed pad MSOP package.

The LT3759 data sheet gives a complete description of the part, operation and application information. The data sheet must be read in conjunction with this quick start guide for demo circuit 1787A.

Design files for this circuit board are available at http://www.linear.com/demo

L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners.

2.8 12 36 V

11.64 12.0 12.36 V

= 1A 90 mV

OUT

= 1A 91 %

OUT

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1

DEMO MANUAL DC1787A

QUICK START PROCEDURE

Demo circuit 1787A is easy to set up to evaluate the performance of the LT3759. Refer to Figure 1 for proper measurement equipment setup and follow the procedure.

1. With power off, connect the input power supply to the (E1) and GND (E2) terminals on the demo circuit.

V

IN

NOTE: Minimize the voltage drop and transient on the input wires between the power supply and input terminals of the demo circuit.

2. Connect load to the V

on the demo circuit. Connect voltage and current meters as shown in Figure 1. Preset the load to 0.5A or less, and V

3. Place jumpers in the following positions for a typical

12V application:

4. Turn on the power supply at the input. Slowly increase

V

NOTE: Make sure the input voltage is within the range. If higher operating voltage is required, power components with higher voltage ratings should be used. The maximum input voltage of LT3759 is 42V.

supply to be 0V.

IN

EN (JP1) SYNC (JP2)

ON OFF

to 3.0V.

IN

(E6) and GND (E5) terminals

OUT

NOTE: The demo circuit configures the shutdown voltage at typical 2.5V, which means that the input voltage can be dropped to as low as 2.5V, once it starts up. The startup voltage is 3.0V but can be adjusted by changing R1 and R3 values.

5. Check for the proper output voltages. The output should be regulated at 12V (±3%).

NOTE: If there is no output, or output is out of spec, temporarily disconnect the load from the demo board. Make sure the load current is set within spec, and the power supply current capability is above 4A.

6. Once the proper output voltage is established, adjust the input and load within the operating range and observe the output voltage regulation, ripple voltage, efficiency and other parameters. Typical efficiency curve, regulation, and operation waveforms are shown in Figures 3 and 4, respectively.

NOTE: When measuring the input or output voltage ripples, care must be taken to avoid a long ground lead on the oscilloscope probe. Measure the input or output voltage ripple by touching the probe tip directly across the V and GND, or V proper scope probe technique.

and GND terminals. See Figure 2 for

OUT

IN

NOTE: The output current capability depends on the input voltage, as can be seen in Figure 3. Proper cooling is necessary for overload operations.

2

dc1787af

QUICK START PROCEDURE

Figure 1. Proper Measurement Equipment Setup

DEMO MANUAL DC1787A

dc1787af F01

INPUT OR OUTPUT CAPACITOR

dc1787af F02

Figure 2. Proper Scope Probe Placement for Measuring Input or Output Ripple

95

90

85

80

EFFICIENCY (%)

75

70

100 300 500 600 700 800200 400 900 1000

LOAD CURRENT (mA)

VIN = 2.8V VIN = 4V VIN = 12V

dc1787af F03

dc1787af F04

Figure 3. Efficiency Curves Figure 4. Short Circuit Waveforms with Frequency Foldback

VO: 10V/DIV

: 50V/DIV

V

DS

: 5A/DIV

I

SW

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3

DEMO MANUAL DC1787A

PARTS LIST

ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER

Required Circuit Components

1 2 CIN1, CIN2 CAP., X7R, 10µF, 50V, 10%, 1210 MURATA, GRM32ER71H106KA12L

2 1 CIN3 CAP., ELECT., 22µF, 50V, C-CE-BS-6.3X6.0 SUN ELECT., 50CE22BS

3 2 COUT1, COUT2 CAP., X5R, 47µF, 16V, 10%, 1210 MURATA, GRM32ER61C476KE15L

4 1 C1 CAP., X7R, 4.7µF, 50V, 20%, 1210 MURATA, GRM32ER71H475KA88L

5 1 C2 CAP., X7R, 1µF, 50V 10%, 0805 MURATA, GRM21BR71H105KA12L

6 1 C3 CAP., X5R, 4.7µF, 16V, 10%, 0805 MURATA, GRM219R61C475KE15D

7 1 C5 CAP., X7R, 68nF, 50V, 0603 NIC, NMC0603X7R682K50F

8 1 C6 CAP., X7R, 0.1µF, 25V, 10%, 0603 TDK, C1608X7R1E104K

9 1 C7 CAP., C0G, 470pF, 50V, 5%, 0603 MURATA, GCM1885C1H471JA16D

10 1 D3 DIODE, SCHOTTKY, 3A, POWERDI5 DIODES/ZETEX, PDS360-13

11 1 L1 IND, 15µH, L-DUAL-DRQ127 COILTRONICS, DRQ127-150-R

12 1 Q1 MOSFET, N-CHANNEL, LFPAK RENESAS, RJK0652DPB-00-J5

13 1 RCS RES SENSE, 0.005, 1/2W, 1%, 2010 VISHAY, WSL20105L000FEA

14 1 RFBB RES., CHIP, 15.8k, 1/16W, 1%, 0603 VISHAY, CRCW060315K8FKEA

15 1 RFBS RES., CHIP, 102k, 1/16W, 1%, 0603 VISHAY, CRCW0603102KFKEA

16 1 R1 RES., CHIP, 249k, 1/16W, 1%, 0603 VISHAY, CRCW0603249KFKEA

17 1 R2 RES., CHIP, 100k, 1/16W, 5%, 0603 VISHAY, CRCW0603100KJNEA

18 1 R3 RES., CHIP, 255k, 1/16W, 1%, 0603 VISHAY, CRCW0603255KFKEA

19 1 R4 RES., CHIP, 1.43k, 1/16W, 1%, 0603 VISHAY, CRCW06031K43FKEA

20 1 R5 RES., CHIP, 27.4k, 1/16W, 1%, 0603 VISHAY, CRCW060327K4FKEA

21 1 R6 RES., CHIP, 0, 0603 VISHAY, CRCW06030000Z0ED

22 1 U1 I.C. LT3759EMSE, MSE12 LINEAR TECH.,LT3759EMSE

Hardware/Components (For Demo Board Only)

1 7 E1, E2, E3, E4, E5, E6, E7 TESTPOINT, TURRET, .094" MILL-MAX, 2501-2-00-80-00-00-07-0

2 2 JP1, JP2 JMP, 3-PIN, 1 ROW .079CC SAMTEC, TMM-103-02-L-S

3 2 SHUNTS AS SHOWN ON

ASSY DWG

4 2 STENCILS BOTH SIDES DC1787A-2

Additional Demo Board Circuit Components

1 0 D1 DIODE, FAST SWITCHING, 1N4148WT, SOD523F OPT

SHUNT, .079" CENTER SAMTEC, 2SN-BK-G

4

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SCHEMATIC DIAGRAM

09-30-11

1

ZHONGMING Y.

REVISION HISTORY

DESCRIPTION DATEAPPROVEDECO REV

PRODUCTION1

_

2

3

GNDE5GND

E5

L1B

15uH

L1B

15uH

DRQ127-150-R

L1A

15uH

L1A

15uH

COUT2

COUT1

2 4

1 3

47uF

+VOUT

16V

1210

D3

C1

E6

+VOUT

PDS360D3PDS360

3

50V

4.7uF

RFBS

R2

+VOUT

2 1

102k

100kR2100k

12V /

1210

*

VIN > 4V

0.5A VIN > 2.8V

1A

*

RFBB

15.8k

RFBB

15.8k

U1

C

+VOUT

2

6

R60R6

D1

1N4148WT

0

FBX

2

1

10

DRIVE

PGOOD

VIN

11

12

OPT

C2

Q1

RJK0652DPB

53

4

1uF

50V

0805

1uF

50V

0805

8

GATE

INTVCC9SS

EN/UVLO

DEMO MANUAL DC1787A

.VER.ON CI

2

SYNCE7SYNC

E7

ON

OFF

ON

OFF

JP2

SYNC

132

RCS

0.005

2010

RCS

0.005

2010

2 1

7

SYNC

SENSE

VC

3

1

5

GND

13

RT

4

www.linear.com

Fax: (408)434-0507

Milpitas, CA 95035

Phone: (408)432-1900

1630 McCarthy Blvd.

LTC Confidential-For Customer Use Only

Milpitas, CA 95035

Phone: (408)432-1900

1630 McCarthy Blvd.

LTC Confidential-For Customer Use Only

Milpitas, CA 95035

Phone: (408)432-1900

1630 McCarthy Blvd.

LTC Confidential-For Customer Use Only

LT3759EMSE

DEMO CIRCUIT 1787A

TECHNOLOGY

SCHEMATIC

SEPIC CONVERTER WITH WIDE INPUT VOLTAGE RANGE

N/A

SIZE

TITLE:

KIM T.

ZHONGMING Y.

APPROVALS

PCB DES.

APP ENG.

CUSTOMER NOTICE

LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A

CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;

HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO

VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL

APPLICATION. COMPONENT SUBSTITUTION AND PRINTED

CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT

PERFORMANCE OR RELIABILITY. CONTACT LINEAR

LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A

CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;

LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A

CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;

TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.

HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO

VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL

APPLICATION. COMPONENT SUBSTITUTION AND PRINTED

CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT

PERFORMANCE OR RELIABILITY. CONTACT LINEAR

TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.

HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO

VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL

APPLICATION. COMPONENT SUBSTITUTION AND PRINTED

CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT

PERFORMANCE OR RELIABILITY. CONTACT LINEAR

TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.

11MP 25:21 ,1102/03/90

SHEET OF

1

2

DATE:

SCALE = NONE

3

SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.

THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND

4

CIN2

10uF

50V

1210

CIN2

10uF

50V

1210

CIN1

10uF

50V

1210

CIN1

10uF

50V

1210

VIN

CIN3

22uF

50V

CIN3

22uF

50V

SUN ELECT

50CE22BS

SUN ELECT

VIN

+

2.8V - 36V

50CE22BS

E2

GNDE2GND

5

E1

D D

Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.

PGOOD

E3

PGOODE3PGOOD

LT3759EMSE

R1

249kR1249k

132

JP1

EN/UVLO

RUN

E4

EN/UVLO

C

R3

SHDN

C3

4.7uF 16V

255kR3255k

0805

R5

27.4kR527.4k

R4

1.43kR41.43k

C5

68nFC568nF

C7

470pFC7470pF

C6

0.1uFC60.1uF

1. ALL RESISTORS ARE IN OHMS, 0603.

NOTES: UNLESS OTHERWISE SPECIFIED

B B

A A

4

5

ALL CAPACITORS ARE IN MICROFARADS, 0603.

2. INSTALL SHUNTS AS SHOWN.

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DEMO MANUAL DC1787A

DEMONSTRATION BOARD IMPORTANT NOTICE

Linear Technology Corporation (LTC) provides the enclosed product(s) under the following AS IS conditions:

This demonstration board (DEMO BOARD) kit being sold or provided by Linear Technology is intended for use for ENGINEERING DEVELOPMENT OR EVALUATION PURPOSES ONLY and is not provided by LTC for commercial use. As such, the DEMO BOARD herein may not be complete in terms of required design-, marketing-, and/or manufacturing-related protective considerations, including but not limited to product safety measures typically found in finished commercial goods. As a prototype, this product does not fall within the scope of the European Union directive on electromagnetic compatibility and therefore may or may not meet the technical requirements of the directive, or other regulations.

If this evaluation kit does not meet the specifications recited in the DEMO BOARD manual the kit may be returned within 30 days from the date of delivery for a full refund. THE FOREGOING WARRANTY IS THE EXCLUSIVE WARRANTY MADE BY THE SELLER TO BUYER AND IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE. EXCEPT TO THE EXTENT OF THIS INDEMNITY, NEITHER PARTY SHALL BE LIABLE TO THE OTHER FOR ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES.

The user assumes all responsibility and liability for proper and safe handling of the goods. Further, the user releases LTC from all claims arising from the handling or use of the goods. Due to the open construction of the product, it is the user’s responsibility to take any and all appropriate precautions with regard to electrostatic discharge. Also be aware that the products herein may not be regulatory compliant or agency certified (FCC, UL, CE, etc.).

No License is granted under any patent right or other intellectual property whatsoever. LTC assumes no liability for applications assistance,

customer product design, software performance, or infringement of patents or any other intellectual property rights of any kind.

LTC currently services a variety of customers for products around the world, and therefore this transaction is not exclusive.

Please read the DEMO BOARD manual prior to handling the product. Persons handling this product must have electronics training and

observe good laboratory practice standards. Common sense is encouraged.

This notice contains important safety information about temperatures and voltages. For further safety concerns, please contact a LTC application engineer.

Mailing Address:

Linear Technology

1630 McCarthy Blvd.

Milpitas, CA 95035

Linear Technology Corporation

6

1630 McCarthy Blvd., Milpitas, CA 95035-7417

(408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com

dc1787af

LT 1111 • PRINTED IN USA