DC1687A - LINEAR TECHNOLOGY

dc1687af

DEMO MANUAL DC1687A

Description

LTC3115EDHD-1

40V, 2A Synchronous

Buck-Boost DC/DC Converter

Demonstration circuit 1687A features the LTC

3115-1, a

high voltage monolithic synchronous buck-boost converter.

The DC1687A demo board has two user selectable operat-

ing modes: Burst Mode

operation and forced continuous

operation (fixed frequency PWM) (JP1). There is also an

accurate programmable RUN pin which is used to enable

the converter (JP2).

The DC1687A operates with a 2.7V to 40V input volt-

age range. The demo board has been designed with the

output voltage set to 5.0V. The LTC3115-1 incorporates a

proprietary low noise switching algorithm which optimizes

efficiency with input voltages above, below or equal to the

output voltage and ensures seamless transitions between

operating modes.

The demo board has been programmed to operate at 1MHz

in PWM mode to optimize small size with high efficiency

operation.

L, LT, LTC, LTM, µModule, 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.

performance summary

The demo board also has optional provisions to back

feed VCC in order to increase efficiency in some 5V out-

put applications. There is also a provision for an optional

Schottky diode from SW2 to VOUT for applications where

VOUT is greater than 20V and short circuit protection is

desired. Consult the data sheet for more information on

these options.

Figures 1 and 2 show typical demo board efficiency.

The LTC3115-1 data sheet has detailed information about

the operation, specifications, and applications of the part.

The data sheet should be read in conjunction with this

quick start guide.

Design files for this circuit board are available at

http://www.linear.com/demo

PARAMETER VALUE

Input Voltage Range 2.7V to 40V

VOUT 5.0V

IOUT (See Note 1) 1A For VIN ≥ 3.6V,

2A For VIN > 6V

Efficiency See Figures 1 and 2

Note 1: The Demo Board output current is a function of VIN. Please refer to the data sheet for more information

dc1687af

DEMO MANUAL DC1687A

Quick start proceDure

Using short twisted pair leads for any power connections

and with all loads and power supplies off, refer to Figure 3

for the proper measurement and equipment setup. The

battery/power supply (PS1) should not be connected to

the circuit until told to do so in the procedure below.

When measuring the input or output voltage ripple, care

must be taken to avoid a long ground lead on the oscil-

loscope probe. Measure the input or output voltage ripple

by touching the probe tip directly across the VIN or VOUT

and GND terminals (see Figure 4), or by using an oscil-

loscope probe tip jack.

1. Jumper and PS1 settings to start:

PS1 = OFF

JP1 (PWM) = fixed frequency

JP2 (RUN) = ON

2. With power OFF connect the power supply (PS1) as

shown in Figure 3. If accurate current measurements

are desired (for efficiency calculation for example) then

connect an ammeter in series with the supply as shown.

The ammeter is not required however.

3. Connect a 500mA load to VOUT as shown in Figure 3

(10Ω for VOUT = 5V). Connect an ammeter if accurate

current measurement or monitoring is desired.

4. Turn on PS1 and slowly increase voltage until the volt-

age at VIN is 4.0V.

5. Verify VOUT is ~5.0V.

6. VIN can now be varied between 2.7V and 40.0V. IOUT may

need to be reduced for VIN < 4V. VOUT should remain in

regulation.

7. Load current (IOUT) can also be varied. The maximum

IOUT is a function of VIN and the current limit. Consult

the data sheet for more information on IOUT vs VIN. In

general for VIN > 3.6V IOUT can be increased to 1A. For

VIN > 6V IOUT can be increased to 2A.

8. For operation in Burst Mode operation move Jumper

JP1 to burst. IOUT is limited in Burst Mode operation.

See the data sheet for more information.

9. NOTE: If VOUT drops out of regulation, check to be sure

the maximum load has not been exceeded, or that VIN

is not below the minimum value for regulation (see data

sheet)

100

5 10 15 20 25 30 35 40

EFFICIENCY (%)

VIN (V)

LOAD = 1A

LOAD = 500mA

100

5 10 15 20 25 30 35 40

EFFICIENCY (%)

VIN (V)

LOAD = 300mA

LOAD = 200mA

LOAD = 100mA

Figure 1. DC1687A Efficiency in PWM Mode Figure 2. DC1687A Efficiency in Burst Mode Operation

dc1687af

DEMO MANUAL DC1687A

Quick start proceDure

Figure 3. Proper Measurement Equipment Setup

Figure 4. Measuring Input or Output Ripple

GND

VIN

dc1687af

DEMO MANUAL DC1687A

parts List

ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER

Required Circuit Components

1 2 C1, C2 CAP, CER, 0.10µF, 16V, X7R, ±20%, 0402 TDK, C1005X7R1C104M

2 1 C4 CAP, CER, 33pF, 50V, C0G, 5%, 0402 TDK, C1005C0G1H330J

3 1 C6 CAP, CER, 47µF, 10V, 20%, X5R, 1812 TDK, C4532X5R1A476M

4 1 C7 CAP, CER, 1.0µF, 25V, X5R, 0603 TDK, C1608X5R1E105M

5 1 C8 CAP, CER, 3300pF, 50V, 5%, NP0, 0603 TDK, C1608C0G1H332J

6 1 C9 CAP, CER, 4.7µF, 6.3V, X5R, 20%, 0603 TDK, C1608X5R0J475M

7 1 C10 CAP, CER, 4.7µF, 50V, 20%, X7R, 1812 TDK, C4532X7R1H475M/2.00

8 1 C11 CAP, CER, 10pF, 50V, C0G, 0402 TDK, C1005C0G1H100D

9 1 C12 CAP, CER, 1.0µF, 50V, X7R, 20%, 1206 TDK, C3216X7R1H105M

10 1 C13 CAP, CER, 0.1µF, 50V, 20%, X7R, 0805 TDK, C2012X7R1H104M/0.85

11 1 L1 INDUCTOR, 10µH, ±20% COILCRAFT, MSS1048-103MLB

12 2 R1, R6 RES, 1.00MΩ, 1/16W, 1%, 0402, SMD VISHAY, CRCW04021M00FKED

13 1 R2 RES, 249kΩ, 1/16W, 1%, 0402, SMD VISHAY, CRCW0402249KFKED

14 1 R3 RES, 15.0kΩ, 1/10W, 1%, 0402, SMD PANASONIC, ERJ-2RKF1502X

15 1 R4 RES, 60.4kΩ, 1/10W, 1%, 0402, SMD PANASONIC, ERJ-2RKF6042X

16 1 R7 RES, 47.5kΩ, 1/16W, 1%, 0402, SMD VISHAY, CRCW040247K5FKED

17 1 U1 40V, 2A Buck Boost DC/DC Converter LINEAR TECHNOLOGY, LTC3115EDHD-1

Additional Demo Board Circuit Components

1 0 C3 CAP, CER, 1000PF, 50V, 20%, X7R, 0402 (OPT) TDK, C1005X7R1H102M

2 0 C5 CAP, ALUM, 150µF, 50V, 20%, RADIAL (OPT) PANASONIC, EEU-FM1H151

3 0 D1 DIODE SCHOTTKY, 20V, 1A, SOD323 (OPT) NXP SEMI, PMEG2010EA

4 0 D2 DIODE SCHOTTKY, 60V, 3A, SMA (OPT) DIODES INC.,B360A-13

5 0 R5 RES, 0402 (OPT)

Hardware For Demo Board Only:

1 4 E1–E4 TP, TURRET, 0.094", PBF 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 XJP1, XJP2 SHUNT, .079" CENTER SAMTEC, 2SN-BK-G

4 4 SPACER STACKING #4 SCREW NYLON .500" KEYSTONE, 8833

dc1687af

DEMO MANUAL DC1687A

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 representa-

tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.

schematic Diagram

RUN

VCC

VOUT

VCC

PWM

RUN

PWM

VIN

REVISION HISTORY

DESCRIPTION DATEAPPROVEDECO REV

J.NOONPRODUCTION FAB

- 2 02-08-12

REVISION HISTORY

DESCRIPTION DATEAPPROVEDECO REV

J.NOONPRODUCTION FAB

- 2 02-08-12

REVISION HISTORY

DESCRIPTION DATEAPPROVEDECO REV

J.NOONPRODUCTION FAB

- 2 02-08-12

SIZE

DATE:

.VER.ON CI

SHEET OF

TITLE:

APPROVALS

PCB DES.

APP ENG.

TECHNOLOGY Fax: (408)434-0507

Milpitas, CA 95035

Phone: (408)432-1900

1630 McCarthy Blvd.

LTC Confidential-For Customer Use Only

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

TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.

THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND

SCHEMATIC

SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.

SCALE = NONE

www.linear.com

DEMO CIRCUIT 1687A

N/A

LTC3115EDHD-1

J.NOON

02-08-12

40V, 2A BUCK BOOST DC / DC CONVERTER

SIZE

DATE:

.VER.ON CI

SHEET OF

TITLE:

APPROVALS

PCB DES.

APP ENG.

TECHNOLOGY Fax: (408)434-0507

Milpitas, CA 95035

Phone: (408)432-1900

1630 McCarthy Blvd.

LTC Confidential-For Customer Use Only

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

TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.

THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND

SCHEMATIC

SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.

SCALE = NONE

www.linear.com

DEMO CIRCUIT 1687A

N/A

LTC3115EDHD-1

J.NOON

02-08-12

40V, 2A BUCK BOOST DC / DC CONVERTER

SIZE

DATE:

.VER.ON CI

SHEET OF

TITLE:

APPROVALS

PCB DES.

APP ENG.

TECHNOLOGY Fax: (408)434-0507

Milpitas, CA 95035

Phone: (408)432-1900

1630 McCarthy Blvd.

LTC Confidential-For Customer Use Only

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

TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.

THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND

SCHEMATIC

SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.

SCALE = NONE

www.linear.com

DEMO CIRCUIT 1687A

N/A

LTC3115EDHD-1

J.NOON

02-08-12

40V, 2A BUCK BOOST DC / DC CONVERTER

FIXED FREQ

BURST MODE

PWM

SYNCH

OFF

UNLESS NOTED:

RESISTORS: OHMS, 0402, 1%

CAPACITORS: uF, 0402

0603

RUN

B360A

OPT

B360A

OPT

0.1uF

C11

10pF

C11

10pF

VOUT

5.0V / 2A

VOUT

5.0V / 2A

PMEG2010EA

OPT

PMEG2010EA

OPT

0.1uF

15k

OPT

GND

OPT

C10

4.7uF

50V

1812

C10

4.7uF

50V

1812

JP1JP1

C12

1uF

50V

1206

C12

1uF

50V

1206

1uF

25V

0603

1uF

25V

0603

10uH

3300pF

33pF

OPT

C13

0.1uF

0805

C13

0.1uF

0805

47.5k

LTC3115EDHD-1

VIN

PVIN

PVCC

VCC

RUN 1

PWM/SYNC

GND

PGND

PVOUT 3

VC 6

FB 7

BST1

SW1 15

BST2 12

SW2 2

4.7uF

6.3V

0603

4.7uF

6.3V

0603

JP2JP2

249k

60.4k

VIN

2.7V - 40V

VIN

2.7V - 40V

47uF

10V

1812

47uF

10V

1812

dc1687af

DEMO MANUAL DC1687A

Linear Technology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7417

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

 LINEAR TECHNOLOGY CORPORATION 2012

LT 0412 • PRINTED IN USA

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 applica-

tion engineer.

Mailing Address:

Linear Technology

1630 McCarthy Blvd.

Milpitas, CA 95035