Datasheet LTC3124 Datasheet (Linear Technology)

DESCRIPTION

DEMO MANUAL DC1859A

LTC3124

Dual Phase Synchronous

Step-Up DC/DC Converter

Demonstration circuit 1859A is a dual phase single output DC/DC boost converter featuring the LT

C®3124. The

DC1859A operates over 1.8V to 5.5V input and generates 12V at up to 1.5A from a 5V input. The maximum output current for a 1.8V input is 750mA. Also, the LTC3124 has a 2% precise voltage reference, which can generate an

and achieves over 90% efficiency with a 100mA load. The demonstration circuit can be easily modified to generate different output voltages.

The DC1859 has small circuit footprint. It is a high perfor mance and cost effective solution for generating output voltages up to 15V from inputs as low as 1.8V.

output voltage with 2.2% tolerance if 0.1% voltage divider

Design

resistors are used. The 1MHz switching frequency opera tion results in small and efficient circuit. The converter

®

operates

with only one phase in Burst Mode

PERFORMANCE SUMMARY

PARAMETER CONDITION MIN TYP MAX UNITS

Minimum Input Voltage I

Maximum Input Voltage I

V

OUT

Output Voltage Ripple V

Nominal Switching Frequency 1 MHz

operation

Specifications are at TA = 25°C

= 0A to 0.75A 1.8 V

OUT

= 0A to 1.5A 5.5 V

OUT

VIN = 1.8V to 5.5V, I

= 5V, I

IN

-

http://www.linear.com/demo/DC1859A

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

OUT

= 1.5A 100 mV

OUT

files for this circuit board are available at

= 0A 12 V ±4%

P-P

-

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1

DEMO MANUAL DC1859A

QUICK START PROCEDURE

Demonstration circuit 1859 is easy to set up to evaluate the performance of the LTC3124. For proper measurement equipment procedure below:

NOTE: When measuring the input or output voltage ripple, care must be taken to minimize the length of oscilloscope probe ground lead. Measure the input or output voltage ripple by connecting the probe tip directly across the VIN or VOUT and GND terminals as shown in Figure 2.

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

and GND.

2. Keep the load set to 0A or disconnected.

setup refer to Figure 1 and follow the

IN

3. Turn the input power source on and slowly increase the input voltage. Be careful not to exceed 5.5V.

NOTE: Make sure that the input voltage V

exceed 5.5V.

4. Set the input voltage to 5V and check for the proper output voltage of 12V. If there is no output, temporarily disconnect the load to make sure that the load is not set too high.

5. Once the proper output voltage is established, adjust the load and observe the output voltage regulation, ripple voltage, efficiency and other parameters.

does not

IN

2

Figure 1. Proper Measurement Equipment Setup

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QUICK START PROCEDURE

EFFICIENCY (%)

95

dc1859a F03

10000

DEMO MANUAL DC1859A

+ –

Figure 2. Measuring Input or Output Ripple

C

OUT

V

OUT

Changing the Output Voltage

To change the output voltage from the programmed 12V, change the voltage divider resistors connected to LTC3124 FB pin (see the schematic on page 5).

Converter Output Current

The DC1859 output current capability depends on the input voltage. Typical performance of DC1859A is shown in Figure 3. As can be seen from Figure 3, the maximum output current is 800mA with 2.6V input and 2A with 5V input. The efficiency is high at light loads thanks to phase shedding in BURST mode. By disabling one phase the related switching losses are reduced and the efficiency is maximized.

GND

Output Load Step Response

The load step response of DC1859A is dependent on the amount and type of output caps used. If higher load steps need to be handled more output capacitance can be added in order to keep the voltage transients at the desired level. The load step transients are shown in Figure 4. Other types of low ESR and high value capacitors can

be used if space

is available to reduce load transients to desired level.

Burst Mode OPERATION

90

85

80

PWM MODE

10010

I

(mA)

OUT

VIN = 2.6V

= 5V

V

IN

75

70

65

60

1 1000

Figure 3. The Efficiency Is Maximized for Light Loads by Shedding One Phase in Burst Mode Operation. The Efficiency Is Over 90% at Higher Loads and It Reaches 92% at 800mA Load

Figure 4. The LTC3124 Has Excellent Load Step Response with Small Output Capacitors Thanks to High Switching Frequency and Fast Feedback Loop Compensation

Start-Up and Soft-Start Function

The DC1859 features internal 10ms soft-start circuit that prevents input current surge at start-up. The soft-start circuit also prevents output voltage overshoot when output voltage ramp reaches regulation.

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3

DEMO MANUAL DC1859A

QUICK START PROCEDURE

Figure 5. The DC1859 Ramps the Output Slowly at Start-Up without Generating an Input Current Surge

PARTS LIST

Output Short Circuit Protection

The LTC3124 features safe short-circuit and thermal protection. The part can operate continuously with output shorted while maintaining a maximum set current limit. The peak switch current is reduced during overload to about 2A and is restored to 3.5A once the output exceeds 1.5V.

ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER

Required Circuit Components

2 1 C2 CAP, 0805 10µF 10% 10V X5R MURATA GRM21BR61A106KE19L

3 1 C3 CAP, 0603 4.7µF 10% 10V X5R AVX 0603ZD475K AT2A

4 1 C4 CAP, 0603 0.1µF 10% 25V X7R AVX 06033C104K AT2A

5 2 C5, C6 CAP, 1206 22µF 20% 25V X5R MURATA GRM31CR61E226ME15L

7 1 C8 CAP, 0805 1µF 20% 16V X5R AVX 0805YD105M AT2A

8 1 C9 CAP, 0603 680pF 10% 25V X7R AVX 06033C681K AT2A

9 1 C10 CAP, 0603 56pF 5% 50V C0G AVX 06035A560JAT2A

12 2 L1, L2 IND, 4.7µH COILCRAFT XAL6060-472MEC

14 1 R1 RES, 0603 28k 1% 1/10W VISHAY CRCW060328K0FKEA

16 1 R4 RES, 0603 1M 1% 1/10W VISHAY CRCW06031M00FKEA

17 1 R5 RES. 0603 110k 1% 1/10W VISHAY CRCW0603110KFKEA

18 1 R6 RES, 0603 51.1k 1% 1/10W VISHAY CRCW060351K1FKEA

19 2 R8, R9 RES, 0603 1M 5% 1/10W VISHAY CRCW06031M00JNEA

20 1 U1 IC, DC/DC CONVERTER LINEAR TECH. LTC3124EDHC#PBF

Additional Demo Board Circuit Components

1 0 C1, C11 CAP. 7343 OPTION OPTION

6 0 C7 CAP, 0603 OPTION OPTION

15 0 R3, R7 RES, 0603 OPTION OPTION

Hardware: For Demo Board Only

10 6 E1, E2, E3, E4, E5, E6 TURRET MILL MAX 2501-2-00-80-00-00-07-0

11 2 JP1, JP2 HEADER, 3 PIN SINGLE ROW SULLINS, NRPN031PAEN-RC

13 4 MH1, MH2, MH3, MH4 STANDOFF, SNAP ON KEYSTONE_8831

21 2 JP1, JP2 SHUNT SAMTEC 2SN-BK-G

4

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DEMO MANUAL DC1859A

5

4

3

2

1

11

SCHEMATIC DIAGRAM

2

ON

1.5A [1]

12V

C8

C6

C5

0.1uFC40.1uF

1uF

C11

+

22uF

16

E5

25V

OPT

25VC522uF

25V

25VC622uF

25V

CAP

GNDE5GND

15

VOUTB

13NC14

VOUTA

E6SDE6

12SD11

SGND

VOUT

E4

VOUT

C4

SD

RUN

VIN

9

10

FB

ON

132

R91MR9

1M

R3

OPTR3OPT

C7

R41M1%R41M

1%

C10

56pF

C10

56pF

C9

680pFC9680pF

VC

17

EXPOSED PAD

OFF

R7

JP2

R6

OPTR7OPT

OPTC7OPT

51.1k

R5

1%

110k

1%R5110k

1%

www.linear.com

Milpitas, CA 95035

Phone: (408)432-1900

Milpitas, CA 95035

Phone: (408)432-1900

Milpitas, CA 95035

Phone: (408)432-1900

Fax: (408)434-0507

1630 McCarthy Blvd.

LTC CONFIDENTIAL - FOR CUSTOMER USE ONLY

TECHNOLOGY

MI

APPROVALS

PCB DES.

DC/DC CONVERTER

DUAL PHASE SYNCHRONOUS STEP-UP

SCHEMATIC

TITLE:

GORAN P.

APP ENG.

SHEET OF

LTC3124EDHC

DEMO CIRCUIT 1859A

Wednesday, June 25, 2014

IC NO. REV.

N/A

SIZE

DATE:

SIZE

DATE:

SIZE

DATE:

SCALE = NONE

PGNDA

SWA

4

3

Coilcraft

XAL6060-472

GNDE2GND

C C

VIN

5

E3

U1

L1

4.7uH

VIN

E1

D D

1

Coilcraft

XAL6060-472

C2

10V

10uF

(OPT)

C1

+

VIN

1.8V - 5.5V

L2

2

E2

4.7uH

PGNDB

SWB

LTC3124EDHC

U1

PWM/SYNC

VCC

8

6

7

C3

4.7uF

C3

4.7uF

MODE

PWM/SYNC

RT

132

R1

10V

R81MR8

BURST

28k

1%R128k

1%

1M

PWM

JP1

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

LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A

CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;

HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO

LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A

CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;

HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO

[1] OUTPUT WITH 5V INPUT. SEE QSG FOR OTHER INPUTS.

NOTE: UNLESS OTHERWISE SPECIFIED,

B B

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

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.

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.

A A

SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.

THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND

SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.

THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND

SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.

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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.

5

DEMO MANUAL DC1859A

DEMONSTRATION BOARD IMPORTANT NOTICE

Linear Technology Corporation (LT C ) 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 LT C 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 LT C 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. LT C assumes no liability for applications assistance,

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

LT C 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 LT C application engineer.

Mailing Address:

Linear Technology

1630 McCarthy Blvd.

Milpitas, CA 95035

6

Linear Technology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7417

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

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LT 1014 REV A • PRINTED IN USA

 LINEAR TECHNOLOGY CORPORATION 2014