Linear Technology DC1980A Quick setup guide

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dc1980af
DEMO MANUAL DC1980A
Description
LT3514
Triple Step-Down Switching Regulator
with 100% Duty Cycle Operation
Demonstration circuit 1980A is a triple current mode PWM
step-down DC/DC converter featuring the LT
®
3514. The
demo circuit is designed for 5V, 3.3V and 1.8V outputs
from a 5.4V to 36V input. The current capability of 5V
and 1.8V outputs is 1A and the 3.3V output is capable of
2A output. Individual soft-start and current limit for each
output as well as frequency synchronous function simplify
the complex design of triple-output power converters.
Each converter is synchronized to either a common ex-
ternal clock input or a resistor programmable 250kHz to
2.2MHzinternaloscillator.Programmablefrequencyallows
optimization between efficiency and external component
size. Each output can be independently disabled using its
own RUN/SS pin.
The LT3514 data sheet gives complete description of the
device, operation and application information. The data
sheet must be read in conjunction with this quick start
guide for the demo circuit 1980A.
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.
performance summary
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VIN Input Supply Range 5.4 36 V
VOUT1 Output Voltage 1 4.85 5 5.15 V
VOUT3 Output Voltage 3 3.2 3.3 3.4 V
VOUT4 Output Voltage 4 1.746 1.8 1.854 V
Frequency Switching Frequency VIN = 12V 0.9 1 1.1 MHz
IOUT1 VOUT1 Maximum Output Current VIN = 5.4V ~ 36V 1 A
Specifications are at TA= 25°C
Figure 2. Thermal Image at VIN = 12V, f = 1MHz with
IOUT1 = IOUT4 = 1A and IOUT3 = 2A
Figure 1. System Efficiency at f = 1MHz with IOUT1 = IOUT4 = 1A
and IOUT3 = 2A
VIN (V)
5 15 2510 20 35
30 40
EFFICIENCY (%)
95
100
90
85
80
75
70
60
65
DC1980a F01
DC1980a F02

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DEMO MANUAL DC1980A
Quick start proceDure
Demonstration circuit 1980A is easy to set up to evalu-
ate the performance of the LT3514. Refer to Figure 3 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 VIN or VOUT and GND terminals. See Figure 4 for
proper scope probe technique.
1. Place JP1 to JP4 on ON position.
2. With power off, connect the input power supply to VIN
and GND.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
IOUT3 VOUT3 Maximum Output Current VIN = 5.4V ~ 36V 2 A
IOUT4 VOUT4 Maximum Output Current VIN = 5.4V ~ 36V 1 A
VOUT1(AC) VOUT1 Output Ripple VIN = 5.4V ~ 36V, IOUT1 = 1A 25 mV
VOUT3(AC) VOUT3 Output Ripple VIN = 5.4V ~ 36V, IOUT3 = 2A 25 mV
VOUT4(AC) VOUT4 Output Ripple VIN = 5.4V ~ 36V, IOUT4 = 1A 25 mV
performance summary
Specifications are at TA= 25°C
3. Turn on the power at the input.
NOTE. Make sure that the input voltage does not exceed
36V
4. Check for the proper output voltages.
NOTE. 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 voltages are established, adjust
the load within the operating range and observe the
output voltage regulation, ripple voltage, efficiency and
other parameters.

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DEMO MANUAL DC1980A
Quick start proceDure
Figure 3. DC1980A Proper Equipment Setup
Figure 4. Measuring Input or Output Ripple
DC1980a F03
GNDVIN OR VOUT DC1980A F04

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DEMO MANUAL DC1980A
parts List
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
Required Circuit Components
1 1 C1 CAP, X5R, 22µF, 6.3V, 10% 0805 TDK, C2012X5R0J226K
2 1 C3 CAP, X5R, 47µF, 6.3V, 10% 1206 MURATA, GRM31CR60J476KE19L
3 1 C4 CAP, X5R, 22µF, 10V, 10% 0805 TDK, C2012X5R1A226K
4 1 C5 CAP, X5R, 2.2µF, 6.3V, 10% 0603 TDK, C1608X5R0J225K
5 4 C6, C19, C26, C27 CAP, X5R, 1µF, 50V, 10% 0603 TDK, C1608X5R1H105K
6 3 C7, C17, C18 CAP, X7R, 47nF, 10V, 10% 0603 AVX, 0603ZC473KAT2A
7 1 C21 CAP, NP0, 330pF, 50V, 5% 0603 AVX 06035A331JAT2A
8 1 C23 CAP, NP0, 100pF, 50V, 5% 0603 AVX 06035A101JAT
9 2 D1, D4 DIODE, SCHOTTKY BARRIER RECTIFIER ON SEMI, MBRM140T3G
10 1 D3 SCHOTTKY RECTIFIER, SMA VISHAY, B240A-M3
11 1 L1 IND, 8.2µH SUMIDA, CDRH5D28NP-8R2NC
12 1 L3 IND, 4.7µH NIC, NPIM73P4R7MTRF
13 1 L4 IND, 4.2µH SUMIDA, CDRH5D28NP-4R2NC
14 1 L5 IND, 10µH COILCRAFT, XPL2010-103MLB
15 1 R1 RES, CHIP, 12.7k, 1% 1/16W, 0603 VISHAY, CRCW060312K7FKED
16 1 R3 RES, CHIP, 31.6k, 1% 1/16W, 0603 VISHAY, CRCW060331K6FKED
17 1 R4 RES, CHIP, 53.6k, 1%, 1/16W, 0603 VISHAY, CRCW060353K6FKED
18 1 R5 RES, CHIP, 18.2k, 1% 1/16W, 0603 VISHAY, CRCW060318K2FKED
19 1 R6 RES, CHIP, 200k, 5% 1/16W, 0603 VISHAY, CRCW0603200KJNED
20 1 R7 RES, CHIP, 475k, 1% 1/16W, 0603 VISHAY, CRCW0603475KFKED
21 1 R8 RES, CHIP, 100k, 1% 1/16W, 0603 VISHAY, CRCW0603100KFKED
22 3 R9, R11, R12 RES, CHIP, 10k, 1% 1/16W, 0603 VISHAY, CRCW060310K0FKED
23 1 U1 IC, 36V TRIPLE BUCK REGULATOR LINEAR TECHNOLOGY, LT3514EUFD#PBF
Additional Demo Board Circuit Components
1 1 C8 CAP, ALUM, 22µF, 50V, 20% SUN ELECT, 50CE22BS
2 0 C10 (OPT) CAP, X7R, 0.01µF, 50V,10% 0603 TDK, C1608X7R1H103K OPTION
3 0 C11 (OPT) CAP, X7R, 2.2µF, 50V, 10% 1206 MURATA, GCM31CR71H225KA55L
4 3 C12 TO C14 CAP, X7R, 0.1µF, 50V, 10% 0603 MURATA, GRM188R71H104KA93D
5 0 C20, C25, C28 (OPT) CAP, X7R, 0.1µF, 50V, 10% 0603 MURATA, GRM188R71H104KA93D
6 0 C24 (OPT) CAP, 0603
7 0 FB1 (OPT) FERRITE BEAD, OPTION OPTION
8 0 L6 (OPT) IND, 8.2µH OPTION VISHAY, IHLP-2525CZ-01 OPTION
Hardware: For Demo Board Only
1 15 E1 TO E15 TURRET MILL MAX, 2501-2-00-80-00-00-07-0
2 4 JP1 TO JP4 HEADER, 3PIN, 2mm SAMTEC, TMM-103-02-L-S
3 4 xJP1 TO xJP4 SHUNT, 2mm SAMTEC, 2SN-BK-G

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DEMO MANUAL DC1980A
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
5
5
4
4
3
3
2
2
1
1
D D CC
BB
A A
VIN
VOUT3 3.3V / 2A GND
PG
RUN/SS1
SYNC
OPTIONAL CIRCUIT
5.4V - 36V
RUN/SS3 RUN/SS4
GND
(1MHz)
GND VOUT4 1.8V / 1A GND
5V / 1A
VOUT1
1. ALL RESISTORS ARE 0603. ALL CAPACITORS ARE 0603.
NOTE: UNLESS OTHERWISE SPECIFIED
VIN
RUN/SS1
RUN/SS3
RUN/SS4
SYNC
PG
VOUT4
VIN
VOUT4
VOUT3
R7
475K 1%
R7
475K 1%
C7
47nF
10V
C7
47nF
10V
C12
0.1uF
50V
C12
0.1uF
50V
L5
10uH
L5
10uH
R6
200K
R6
200K
E9E9
E14E14
C13
0.1uF
50V
C13
0.1uF
50V
U1 LT3514EUFD U1 LT3514EUFD
VIN
11
DA1 6
FB1 20
VIN
9
SW1 5
NC
2
FB3 21
SW4 7
DA4 8
FB4 19
RT/SYNC
17
SKY
25
SW5
24
EN/UVLO
16
PG
23
RUN/SS1
13
RUN/SS3
15
RUN/SS4
12
GND
29
VIN
26
GND
10
SW3 4
DA3 3
NC
1
VIN
28
NC
14
GND
18
NC
22
GND
27
R11
10k 1%
R11
10k 1%
E4E4
C14
0.1uF
50V C14
0.1uF
50V
JP4
OFFON
RUN/SS3
JP4
OFFON
RUN/SS3
1
3
2
E2E2
C20
OPT
50V
C20
OPT
50V
E3E3
R4 53.6k
1%
R4 53.6k
1%
JP2
OFFON
RUN/SS1
JP2
OFFON
RUN/SS1
1
3
2
R8
100k
1%
R8
100k
1%
VEMIVEMI
R5
18.2k
1%
R5
18.2k
1%
C28
OPT 50V
C28
OPT 50V
E13E13
C3
47uF 6.3V
1206 C3
47uF 6.3V
1206
C1
22uF
6.3V
0805
C1
22uF
6.3V
0805
C26
1uF
50V
C26
1uF
50V
C4 22uF
10V
0805 C4 22uF
10V
0805
R3 31.6k 1% R3 31.6k 1% R1 12.7k 1% R1 12.7k 1%
C21
330pF
C21
330pF
FB1
FERRITE BEAD
FB1
FERRITE BEAD
D3 B240A D3 B240A
JP3
OFF
ON
RUN/SS4
JP3
OFF
ON
RUN/SS4
1
3
2
C5
2.2uF
6.3V
C5
2.2uF
6.3V
C10
0.01uF
50V
C10
0.01uF
50V
R9
10k 1%
R9
10k 1%
R12
10k 1%
R12
10k 1%
E8E8
C17
47nF
10V C17
47nF
10V
C19
1uF
50V
C19
1uF
50V
L6
8.2uH
L6
8.2uH
D4 MBRM140T3G D4 MBRM140T3G
L4
4.2uH
CDRH5D28-4R2
L4
4.2uH
CDRH5D28-4R2
C6
1uF
50V
C6
1uF
50V
E15E15
C24 OPT C24 OPT
E7E7
L3
4.7uH
NPIM73P4R7MTRF
L3
4.7uH
NPIM73P4R7MTRF
C27 1uF
50V
C27 1uF
50V
JP1
ON OFF
EN/UVLO
JP1
ON OFF
EN/UVLO
1
3
2
L1
8.2uH
CDRH5D28-8R2
L1
8.2uH
CDRH5D28-8R2
E1E1
+
C8
22uF
50V
+
C8
22uF
50V
C11
2.2uF
50V
1206
C11
2.2uF
50V
1206
C23
100pF
C23
100pF
E11E11
C25
OPT 50V
C25
OPT 50V
D1 MBRM140T3G D1 MBRM140T3G
E12E12
C18
47nF
10V
C18
47nF
10V
E10E10

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DEMO MANUAL DC1980A
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
[phone] ●FAX: [phone] ●www.linear.com
 LINEAR TECHNOLOGY CORPORATION 2013
LT 0713 • PRINTED IN USA
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 applica-
tion engineer.
Mailing Address:
Linear Technology
1630 McCarthy Blvd.
Milpitas, CA 95035
Copyright © 2004, Linear Technology Corporation

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