Linear Technology DC1940A Demo Manual

DESCRIPTION

DEMO MANUAL DC1940A

Low Quiescent Current,

High Voltage Step-Down

Converter

Demonstration circuit 1940A is a low quiescent current,

®

synchronous buck converter featuring the LTC

3891EUDC. This demo board converts a 16V to 60V voltage to a 12V at 15A output.

The main features of this board include an internal LDO for gate drive power from V

or EXTVCC, RUN and

IN

PGOOD pins, a mode selector that allows the converter to run in constant current mode (CCM), pulse-skipping or

®

Burst Mode

operation, and selectable current limit. The DC1940A supports an adjustable output voltage, soft-start and tracking. The wide input voltage range of 16V to 60V is suitable for double battery automotive and distributed DC power systems where low quiescent current is important.

The LTC3891 data sheet gives a complete description of this part, operation and application information. The data sheet must be read in conjunction with this quick start guide for demo circuit 1940A.

The 60V avalanche rated MOSFETs, which are used on DC1940A, can be operated at their rated voltage. However, if application derating requirements are stricter, MOSFETs with higher voltage rating can be used.

Please note, MOSFETs with higher voltage ratings may affect the efficiency. If 60V MOSFETs are used, the MOSFET avalanche rating and testing is typically done with 30% over voltage margin (78V for 60V rated MOSFET). Please check with particular MOSFET manufacturer to ensure the avalanche voltage rating.

The DC1940A supports the following MOSFET packages: LFPAK, PowerPAK SO-8 and Power 56. The subsequent logic level (SV gate) MOSFETs can be used with DC1940A.

Si7850DP Vishay RJK0651DPB Renesas HAT2266H Renesas BSC100N06LS3 G Infineon FDMS86520L Fairchild

For synchronization to an external clock, remove jumper

JP2 and apply sync signal on terminal SYNC.

Design files for this circuit board are available at

http://www.linear.com/demo

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.

PERFORMANCE SUMMARY

PARAMETER CONDITIONS VALUE UNITS

Minimum Input Supply Voltage 16 V Maximum Input Supply Voltage 60 V Output Voltage Range V Typical Switching Frequency 125 kHz Typical Output Ripple (V Efficiency Typical (V Supply Quiescent Current V Supply Shutdown Current V

, 12V) I

OUT

, 12V) 97 %

OUT

(TA = 25°C)

= 16V to 60V, I

IN

= 15A 80 mV

LOAD

= 24V; V

IN

= 24V 14.7 μA

IN

OUT

= 0A to 5A 12 ± 2% V

OUT1

= 12V, IO = 0A, Burst Mode Operation 50.8 μA

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1

DEMO MANUAL DC1940A

QUICK START PROCEDURE

Demonstration circuit 1940A is easy to set up to evaluate the performance of the LTC3891EUDC. Refer to Figure 1 for proper measurement equipment setup and follow the procedure below:

NOTE: When measuring the input or output voltage ripple, 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 terminals. See Figure 2 for proper scope

V

OUT

probe technique.

1. Place jumper JP1 in the ON position.

2. With power off, connect the input power supply to V

and GND.

IN

or

IN

3. Turn on the power at the input. Check for the proper output voltages:

V NOTE: If there is no output, temporarily disconnect the

4. Once the proper output voltages are established, adjust

= 11.9V to 12.4V

OUT1

load to make sure that the load is not set too high.

the load within the operating range and observe the output voltage regulation, ripple voltage, efficiency and other parameters.

2

DC1940a F01

Figure 1. Proper Measurement Equipment Setup

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QUICK START PROCEDURE

Figure 2. Measuring Input or Output Ripple

VIN

DEMO MANUAL DC1940A

GND

DC1940a F02

99

98

97

96

95

94

93

EFFICIENCY (%)

92

91

90

89

0.01 0.1 1 10 100

16V 24V 48V

LOAD (A)

Figure 3. 12V Output, Efficiency vs Load, Burst Mode Operation, VIN 16V, 24V, 48V

DC1940a F03

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3

DEMO MANUAL DC1940A

PARTS LIST

ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER

Required Circuit Components

1 3 C1, C2, C10 CAP, X7R, 2.2μF 100V 10%, 1812 TDK, C4532X7R2A225K 2 1 C3 CAP, EL, 56μF/63V, F4 SUN EL, 63HVH56M 3 1 C4 CAP, X7R, 0.1μF 100V 10%, 0603 MURATA, GRM188R72A104KA35D 4 1 C5 CAP, NPO,10pF, 50V, 5%, 0603 AVX, 06031A100JAT2A 5 2 C9, C13 CAP, X7R, 0.1μF 50V 10%, 0603 TDK, C1608X7R1H104K 6 1 C6 CAP, X5R, 4.7μF, 16V, 10%, 0805 MURATA, GRM219R61C475KE15D 7 2 C7, C17 CAP, X7R, 1μF 16V, 10%, 0603 TDK, C1608X7R1C105K 8 1 C8 CAP, NPO, 2.2pF 50V, ±0.25pF, 0603 AVX, 06035A2R2CAT

9 1 C12 CAP, X7R, 4700pF, 10V, 5%, 0603 AVX, 0603ZC472JAT2A 10 1 C14 CAP, NPO, 47pF 50V, 5%, 0603 NIC, NMC0603NPO470J50TRPF 11 1 C15 CAP, X7R, 10μF 16V 10%, 1206 MURATA, GCM31CR71C106KA64L 12 1 C16 CAP, SANYO, 150μF, 16V, 20% SANYO, 16TSVPC150 13 1 D1 DIODE, POWER DI-123 DIODES/ZETEX, DFLS1100-7 14 1 L1 IND, 10μH, 7443631000 WÜRTH, 7443631000 15 1 Q1 SILICON N CHANNEL POWER MOSFET LFPAK RENESAS, RJK0651DPB 16 1 Q2 SILICON N CHANNEL POWER MOSFET LFPAK RENESAS, RJK0653DPB 17 1 RS1 RES, 0.003Ω 1W 1% 2512 PANASONIC ERJM1WSF3M0U 18 1 R1 RES, 2.2 1% 1/10W, 0603 VISHAY, CRCW06032R20FNEA 19 3 R2, R8, R10 RES, 0Ω 1% 1/16W, 0603 VISHAY, CRCW06030000Z0EA 20 2 R4, R20 RES, 100k 1% 1/16W, 0603 VISHAY, CRCW0603100KFKEA 21 1 R5 RES, 511k 1% 1/16W, 0805 VISHAY, CRCW0805511KFKEA 22 1 R6 RES, 30.1k 1% 1/10W, 0603 VISHAY, CRCW060330K1FKEA 23 1 R7 RES, 35.7k 1% 1/16W, 0603 VISHAY, CRCW060335K7FKEA 24 1 R13 RES, 100 1% 1/10W, 0603 VISHAY, CRCW0603100RFKEA 25 1 R14 RES, 1M 1% 1/10W, 0805 VISHAY, CRCW08051M00FKEA 26 1 R15 RES, 2Ω 1% 1/16W, 0603 VISHAY, CRCW06032R00FNEA 27 1 R16 RES, 57.6k 1% 1/16W, 0603 VISHAY, CRCW060357K6FKEA 28 1 R17 RES, 15.4k 1% 1/10W, 0603 VISHAY, CRCW060315K4FKEA 29 1 R18 RES, 1k 1% 1/16W, 0603 VISHAY, CRCW06031K00FKEA 30 1 U1 IC, LTC3891EUDC, QFN20EUDC-3X4 LINEAR TECHNOLOGY, LTC3891EUDC

Additional Demo Board Circuit Components

1 R3, R9, R11, C11, R12,

C18, C19, R19, R21 2 C20, C21, C22 CAP, 7343 OPT 3 Q3, Q4 (OPT) MOSFET, LFPAK OPT

Hardware

1 10 E1 TO E10 TESTPOINT, TURRET, 0.094" MILL-MAX, 2501-2-00-80-00-00-07-0 2 4 J1, J2, J3, J4 CONN, BANANA JACK, KEYSTONE-575-4 KEYSTONE 575-4 31JP1 JMP, 3PIN 1 ROW, 0.079" SULLINS, NRPN031PAEN-RC 41JP2 JMP, 3PIN 2 ROW, 0.079" SULLINS, NRPN032PAEN-RC 5 4 MTGS AT 4 CORNERS STANDOFF, NYLON 0.5 1/2" KEYSTONE, 8833(SNAP-ON) 6 2 XJP1, XJP2 SHUNT, 0.079" CENTER SAMTEC, 2SN-BK-G

RES, 0603 OPT

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4

SCHEMATIC DIAGRAM

VICTOR K.PRODUCTION2 03-26-12

1

REVISION HISTORY

DESCRIPTION DATEAPPROVEDECO REV

REVISION HISTORY

DESCRIPTION DATEAPPROVEDECO REV

REVISION HISTORY

DESCRIPTION DATEAPPROVEDECO REV

__

2

0

R20R2

VOUT

R3

OPTR3OPT

INTVCC

R6

30.1KR630.1K

3

R7

511K

10pFC510pF

0805R5511K

0805

35.7KR735.7K

7

20

FREQ

R5

C5

DEMO MANUAL DC1940A

2

SCHEMATIC

TITLE:

VICTOR K

APP ENG.

APPLICATION. COMPONE NT SUBSTITUTION AND PRINTE D

IC NO. REV.

LOW QUIESCENT CURRENT HIGH VOLTAGE STEP-DOWN CONVERTER

SIZE

CIRCUIT BOARD LAYOUT MAY SI GNIFICANTLY AFFECT CIRCUI T

PERFORMANCE OR RELIABIL ITY. CONTACT LINEAR

TECHNOLOGY APPLI CATIONS ENGINEERING FOR ASSI STANCE.

CIRCUIT BOARD LAYOUT MAY SI GNIFICANTLY AFFECT CIRCUI T

PERFORMANCE OR RELIABIL ITY. CONTACT LINEAR

TECHNOLOGY APPLI CATIONS ENGINEERING FOR ASSI STANCE.

CIRCUIT BOARD LAYOUT MAY SI GNIFICANTLY AFFECT CIRCUI T

PERFORMANCE OR RELIABIL ITY. CONTACT LINEAR

TECHNOLOGY APPLI CATIONS ENGINEERING FOR ASSI STANCE.

2

11

SHEET OF

1

LTC3891EUDC

DEMO CIRCUIT 1940A

Monday, March 26, 2012

N/A

DATE:

2

SCALE = NONE

3

THIS CIRCUIT IS P ROPRIETARY TO LINEAR TE CHNOLOGY AND

SUPPLIED FOR US E WITH LINEAR TECHNOLOGY PART S.

THIS CIRCUIT IS P ROPRIETARY TO LINEAR TE CHNOLOGY AND

SUPPLIED FOR US E WITH LINEAR TECHNOLOGY PART S.

THIS CIRCUIT IS P ROPRIETARY TO LINEAR TE CHNOLOGY AND

SUPPLIED FOR US E WITH LINEAR TECHNOLOGY PART S.

GNDE7GND

VOUTJ3VOUT

VOUTE6VOUT

12V / 15A

J3

E6

VOUT

C16

RS1

2512

RS1

2512

0.003

L1

0

100

R13

R100R10

C8

0805

2.2pFC82.2pF

6

5

SENSE-

SENSE+

C6

4.7uF

INTVCC

14

VFB

INTVCC

Q4

OPTQ4OPT

5

VIN

C19

OPT

C19

OPT

C10

2.2uF

VIN

INTVCC

4

Q1

1812

100V

5

4

D1

RJK0651DPBQ1RJK0651DPB

DFLS1100D1DFLS1100

2

R152R15

10

12

BOOST

10uHL110uH

3 2 1

OPTQ3OPT

5

3 2 1

RJK0653DPBQ2RJK0653DPB

5

50V

0.1uF

C13

13

11

TG

BG

SW

GNDJ4GND

E7

J4

1uF

C17

150uF

16V

150uF

16V

16SVPC150M

+

1206

C15

10uF

+

C20

OPT

7343

C20

OPT

7343

C22

OPT

7343

C22

OPT

7343

C21

OPT

7343

C21

OPT

7343

Q3

3 2 1

4

Q2

3 2 1

4

SGND

21

www.linear.com

Fax: (408)434-0507

Milpitas, CA 95035

Phone: (408)432-1900

1630 McCarthy Blvd.

LTC Confidential-For Customer Use Only

Fax: (408)434-0507

Milpitas, CA 95035

Phone: (408)432-1900

1630 McCarthy Blvd.

LTC Confidential-For Customer Use Only

Fax: (408)434-0507

Milpitas, CA 95035

Phone: (408)432-1900

1630 McCarthy Blvd.

LTC Confidential-For Customer Use Only

TECHNOLOGY

LT

APPROVALS

PCB DES.

CUSTOMER NOTICE

LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DES IGN A

CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;

HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO

VERIFY PROPE R AND RELIABLE OPERATION IN THE ACTUAL

LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DES IGN A

CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;

HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO

VERIFY PROPE R AND RELIABLE OPERATION IN THE ACTUAL

LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DES IGN A

CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;

HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO

VERIFY PROPE R AND RELIABLE OPERATION IN THE ACTUAL

C4

0.1uF

100VC40.1uF

100V

VIN17PGOOD9EXTVCC

U1

LTC3891EUDCU1LTC3891EUDC

R1

2.2R12.2

R4

4

VIN

C1

C2

5

J1

E1

VINJ1VIN

VINE1VIN

16 - 60V

D D

100kR4100k

INTVCC

63HVH56M

C3

56uF/63V+C3

56uF/63V

SUN ELECT.

+

2.2uF

100V

1812C12.2uF

100V

1812

2.2uF

100V

1812C22.2uF

100V

1812

J2

GNDJ2GND

VOUT

E2

E3

GNDE2GND

PGOODE3PGOOD

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.

15

R80R8

0

R9

EXTVCCE4EXTVCC

TRACK/SS19RUN4ITH8SGND2SGND3PGND16PLLIN/MODE1ILIM

C7

1uFC71uF

C9

R12

OPT

R12

OPT

R11

OPT

OPTR9OPT

E4

TRACKE5TRACK

C C

0.1uFC90.1uF

R14

0805

R14

0805

1 Meg

VIN

E5

132

RUN

ON

18

R21

OPT

R21

R19

15.4K

R17

C14

4.7nF

C12

C11

OPT

R16

57.6K

JP1JP1

OFF

INTVCC

C18

OPT

47pF

R181KR18

1K

E8

INTVCC

SYNCE8SYNC

B B

OPT

4

FCM

PULSE SKIP

BURST

2

4

MODE

1

3

5 6

JP2JP2

R20

100K

E10

E9

GND

GNDE9GND

NOTES:

1. ALL RESISTORS AND CAPACITORS ARE 0603

2. INSTALL SHUNTS AS SHOWN.

A A

3. FOR SYNCHRONIZATION REMOVE JUMP ER JP2 'MODE'

AND CONNECT SOURCE OF THE SYNC SIGNAL TO

TERMINALS E8 'SYNC' AND E9 'GND'

5

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5

DEMO MANUAL DC1940A

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

Linear Technology Corporation

6

1630 McCarthy Blvd., Milpitas, CA 95035-7417

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

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LT 0612 • PRINTED IN USA