DEMO MANUAL DC1403A
LT3692A
Monolithic Dual Tracking 3.5A
Step-Down Switching Regulator
DESCRIPTION
Demonstration circuit 1403A is a dual current mode PWM
step-down DC/DC converter featuring the LT3692A. The
demo circuit is designed for 5V and 3.3V outputs from a
7V to 36V input. The current capability of each channel is
up to 3A. Individual soft-start, current limit, comparator,
input voltage for each output as well as frequency division
and synchronous and clock output functions simplify the
complex design of dual-output power converters.
Both converters are synchronized to either a common
external clock input or a resistor-programmable 250kHz
to 2.25MHz internal oscillator. At all frequencies, a 180°
phase shift between channels is maintained, reducing
EFFICIENCY GRAPH
100
95
The LT3692A 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 demo circuit 1403A.
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.
VIN = 12V
f = 400kHz
VOUT1 = 5V
90
EFFICIENCY (%)
voltage ripple. Programmable frequency allows optimization between efficiency and external component size.
Each output can be independently disabled using its
own SHDN pin and be placed in a low quiescent current
shutdown mode.
85
VOUT2 = 3.3V
80
75
70
65
60
0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7 3.0
LOAD CURRENT (A)
dc1403a F01
Figure 1. Efficiency vs Load Current
PERFORMANCE SUMMARY
PARAMETER
Specifications are at TA = 25°C
CONDITION
Minimum Input Voltage
VALUE
7V
Maximum Input Voltage
36V
Output Voltage VOUT1
VIN = 7V ~ 36V
Output Voltage VOUT2
VIN = 7V ~ 36V
Switching Frequency
5V ±3%
3.3V ±3%
400kHz ±10%
Maximum Output Current IOUT1
VIN = 7V ~ 36V
3A
Maximum Output Current IOUT2
VIN = 7V ~ 36V
3A
Voltage Ripple VOUT1
VIN = 12V, IOUT1 = 3A
< 20mV
Voltage Ripple VOUT2
VIN = 12V, IOUT2 = 3A
< 20mV
dc1403af
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DEMO MANUAL DC1403A
QUICK START PROCEDURE
Demo circuit 1403A is easy to set up to evaluate the performance of the LT3692A. Refer to Figure 2 for proper
measurement equipment setup and follow this procedure:
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 3 for the proper
scope probe technique.
1. Place JP1 on the SINGLE position.
3. Turn on the power at the input.
NOTE. Ensure 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 ensure 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.
2. With power off, connect the input power supply to VIN1
and GND. If DUAL is selected, connect another input
power supply to VIN2 and GND.
Figure 2. DC1403A Proper Equipment Setup
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DEMO MANUAL DC1403A
QUICK START PROCEDURE
GND
VIN
dc1403a F03
Figure 3. Measuring Input or Output Ripple
ADDITIONAL NOTES
If an EMI filter is desired on VIN1, it can be feasibly installed on the back of the board in the optional circuit area.
However, a trace cut is required for the insertion of the
optional circuit. See Figure 4 for the cut line.
CUT LINE
C
CU
dc1403a F04
Figure 4. Cut Line for the EMI Filter Installation
dc1403af
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DEMO MANUAL DC1403A
PARTS LIST
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
Required Circuit Components
1
2
C2, C3
CAP, 1210 4.7μF 10% 50V X7R
MURATA GRM32ER71H475KA88L
2
2
C4, C5
CAP, 0603 0.47μF 10% 25V X7R
MURATA GRM188R71E474KA12D
3
2
C7, C8
CAP, 1210 100μF 20% 10V X5R
TAIYO YUDEN LMK325ABJ107MM-T
4
2
C10, C11
CAP, 0402 22pF 10% 25V NPO
AVX 04023A220KAT2A
5
2
C12, C13
CAP, 0402 0.1μF 10% 16V X7R
TDK C1005X7R1C104K
6
2
C14, C15
CAP, 0402 680pF 10% 25V X7R
AVX 04023C681KAT2A
7
2
C16, C17
CAP, 0402 33pF 10% 25V NPO
AVX 04023A330KAT
8
1
C24
CAP, 0402 10nF 10% 16V X7R
MURATA GRM155R71C103KA01D
9
2
D1, D5
DIODE, SCHOTTKY SOD323
CENTRAL SEMI CMDSH-4E
10
2
D2, D4
DIODE, SCHOTTKY RECTIFIER SMA
DIODES INC. B340A
11
1
L1
IND, 6.8μH
NIC NPIM74C6R8MTRF
12
1
L2
IND, 4.7μH
NIC NPIM74C4R7MTRF
13
2
R1, R2
RES, 0402 1k Ωs 1% 1/16W
VISHAY CRCW04021K00FKED
14
1
R5
RES, 0402 42.2k Ω 1% 1/16W
VISHAY CRCW040242K2FKED
15
1
R6
RES, 0402 24.9k Ωs 1% 1/16W
VISHAY CRCW040224K9FKED
16
2
R7, R8
RES, 0402 100k Ω 5% 1/16W
VISHAY CRCW0402100KJNED
17
2
R9, R10
RES, 0402 8.06k Ω 1% 1/16W
VISHAY CRCW04028K06FKED
18
2
R11, R12
RES, 0402 100k Ω 1% 1/16W
VISHAY CRCW0402100KFKED
19
2
R13, R14
RES, 0402 30k Ωs 1% 1/16W
NIC NRC04F3002TRF
20
1
R15
RES, 0402 10.2k Ωs 1% 1/16W
VISHAY CRCW040210K2FKED
21
1
R16
RES, 0402 20k Ω 1% 1/16W
VISHAY CRCW040220K0FKED
22
1
R17
RES, 0402 40.2k Ω 1% 1/16W
VISHAY CRCW040240K2FKED
23
1
U1
IC, STEP-DOWN REGULATOR
LINEAR TECH LT3692AEFE
Additional Demo Board Circuit Components
1
2
C1, C21
CAP, 22μF 20% 50V OSCON
SUNCON 50CE22BS
2
0
C6, C9
CAP, 0805 10μF 10% 16V X5R OPTION
MURATA GRM21BR61C106KE15L OPTION
3
0
C18
CAP, 22μF 20% 50V OSCON OPTION
SANYO 50CE22BS OPTION
4
0
C19
CAP, 0603 0.01μF 10% 50V X7R OPTION
AVX 06035C103KAT2A OPTION
5
0
C20
CAP, 1210 2.2μF 10% 50V X7R OPTION
MURATA GRM32ER72A225KA35L OPTION
6
0
C25
CAP, 0402 10nF 10% 16V X7R OPTION
MURATA GRM155R71C103KA01D OPTION
7
0
D3, D6
DIODE, SCHOTTKY SOD323 OPTION
CENTRAL SEMI CMDSH-4E OPTION
8
0
D7, D8
DIODE, OPT
OPTION
9
0
FB1
FERRITE BEAD OPTION
TAIYO YUDEN FBMJ3216HS800 OPTION
10
0
L3
IND, 22μH OPTION
VISHAY IHLP4040DZ-01 OPTION
Hardware for Demo Board Only
1
1
JP1
HEADER, 4-PIN
SAMTEC TMM-104-02--L-S
2
8
TP1, TP2, TP5-TP8, TP16,
TP17
TURRET
MILL-MAX 2501-2-00-80-00-00-07-0
3
9
TP3, TP4, TP9-TP15
TURRET
MILL MAX 2308-2-00-80-00-00-07-0
4
1
JP1
SHUNT, 2mm
SAMTEC 2SN-BK-G
dc1403af
4
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.
A
B
C
TP5
TP3
TP2
TP1
TP13
TP11
TP9
C19
0.01uF
237
0603
L3
C12
R5
42.2K
1%
C10
C4 0.47uF
0603
CMDSH-4E
D1
B340A
D2
R15
10.2k
1%
L1
6.8uH
VIN1
BEAD
IHLP4040DZ-01
237
C20
2.2uF
50V
237
1210
22uH
237,21$/&,5&8,7
FBMJ3216HS800
237
FB1
0.1uF
5
1. ALL CAPACITORS AND RESISTORS ARE 0402.
[2] SEE QUICK START GUIDE FOR DETAILS ON JP1 SETTING
AND INPUT VOLTAGE IMPLEMENTATION ORDER.
+ C18
22uF
50V
237
VIN1
10nF
OPT
C25
4
100K 1%
R13 30k 1%
C16 33pF
C14 680pF
R11
R9 8.06K 1%
22pF
(400kHz)
VIN1
R16
20k
1%
2
38
6
35
NC
NC
NC
NC
NC
DIV
RT/SYNC
VC1
ILIM1
SS1
CMPO1
CMPI1
FB1
3
4
3
17
19
21
31
37
28
29
26
25
24
13
12
C24
7+,6&,5&8,7,635235,(7$5<72/,1($57(&+12/2*<$1'
6833/,(')2586(:,7+/,1($57(&+12/2*<3$576
/,1($57(&+12/2*<+$60$'($%(67())25772'(6,*1$
&,5&8,77+$70((76&86720(56833/,('63(&,),&$7,216
+2:(9(5,75(0$,167+(&86720(5
65(63216,%,/,7<72
9(5,)<3523(5$1'5(/,$%/(23(5$7,21,17+($&78$/
$33/,&$7,21&20321(1768%67,787,21$1'35,17('
&,5&8,7%2$5'/$<2870$<6,*1,),&$17/<$))(&7&,5&8,7
3(5)250$1&(255(/,$%,/,7<&217$&7/,1($5
7(&+12/2*<$33/,&$7,216(1*,1((5,1*)25$66,67$1&(
3
C11
C5 0.47uF
0603
D5
R6
24.9K
1%
CMDSH-4E
R8
100K
VOUT1
R2
1k
1%
VIN2
D8
OPT
IC Change
C13
C3
4.7uF
50V
1210
+ C21
22uF
50V
REVISION HISTORY
DESCRIPTION
R18
(':,1/
0,
2
6&$/( 121(
$33(1*
3&%'(6
$33529$/6
OPT
,&12
DATE
GND
TP15
TEMP
CLKOUT
TP14
TP12
SS2
CMPO2
TP10
TP8
9$
VOUT2
SHDN2
GND
[2]
VIN2
EDWIN L.
APPROVED
1
LT3692AEFE
6+((7 2) 5(9
0F&DUWK\%OYG
0LOSLWDV&$
3KRQH ZZZOLQHDUFRP
)D[
/7&&RQILGHQWLDO)RU&XVWRPHU8VH2QO\
C9
10uF
16V
OPT
0805
TP6
TP4
TP17
TP16
02/23/11
DEMO CIRCUIT 1403A
'$7( Wednesday, February 23, 2011
1$
6,=(
TECHNOLOGY
0.1uF
1
DUAL MONOLITHIC STEP-DOWN
CONVERTER
7,7/( 6&+(0$7,&
C15 680pF
C17 33pF
R14 30k 1%
100K 1%
R10 8.06K 1%
22pF
C8
100uF
10V
1210
R12
B340A
D4
D3
CMDSH-4E
OPT
3
REV
11
R17
40.2k
1%
L2
4.7uH
VIN2
ECO
VOUT2
10nF
DUAL
2
16
18
20
14
23
JP1
CASCADE
SINGLE
&86720(5127,&(
NC
NC
NC
NC
NC
TJ
CLKOUT
VC2
ILIM2
SS2
CMPO2
CMPI2
FB2
VOUT2
IND2
SW2
BST2
SHDN2
VOUT1
2
INPUT MODE
1
Figure 5. Demo Circuit Schematic
15
10
5
3
1
27
30
32
33
34
7
8
VOUT1
IND1
SW1
BST1
SHDN1
LT3692AEFE
U1
9
R7
100K
D7
OPT
D6
CMDSH-4E
OPT
VOUT2
C6
10uF
16V
OPT
0805
C7
100uF
10V
1210
R1
1k
1%
VIN1
4
C2
4.7uF
50V
1210
VOUT1
+ C1
22uF
50V
NOTES: UNLESS OTHERWISE SPECIFIED,
SYNC
SS1
CMPO1
GND
TP7
9$
VOUT1
SHDN1
GND
[2]
VIN1
36
VIN1
D
4
VIN2
22
PGND
39
5
A
B
C
D
DEMO MANUAL DC1403A
SCHEMATIC DIAGRAM
dc1403af
5
DEMO MANUAL DC1403A
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
Copyright © 2004, Linear Technology Corporation
dc1403af
6
Linear Technology Corporation
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