DC1730A - Demo Manual

DEMO MANUAL DC1730A
LT3973
42V, 750mA Step-Down Regulator
with 2.5µA Quiescent Current
DESCRIPTION
Demonstration circuit 1730A features the LT3973, a monolithic step-down switching regulator which consumes only
2.5μA quiescent current. The demo circuit is designed for
a 5V, 750mA output from a 5.6V to 42V input. The wide
input range of the LT3973 allows a variety of input sources
including automotive batteries and 24V industrial supplies.
In order to reduce the number of components and solution
size, the catch diode and boost diode are integrated. The
switching frequency is adjustable up to 2.2MHz. At light
loads, the regulator operates in Burst Mode® to maintain
high efficiency and low output ripple.
The current mode control scheme creates fast transient
response and good loop stability. During short circuit and
PERFORMANCE SUMMARY
PARAMETER
overvoltage conditions, the catch diode current is limited
to protect the part. Users can populate R7 and R8 on the
EN/UVLO pin to provide a programmable undervoltage
lockout. In addition, the shutdown feature can be utilized
by placing jumper JP1 in the OFF position.
The LT3973 data sheet gives a complete description of the
part, operation and application information. The data sheet
must be read in conjunction with this quick start guide for
working on or modifying the demo circuit 1730A.
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.
(TA = 25°C)
CONDITIONS
VALUE
Minimum Input Voltage
5.6V
Maximum Input Voltage
42V
Output Voltage
5.04V±3%
Maximum Output Current
750mA
Typical Switching Frequency
600kHz
VIN = 12V, IOUT = 750mA
Typical Efficiency
84%
90
EFFICIENCY (%)
80
70
60
50
40
0
0.1
0.2
0.3 0.4 0.5 0.6
LOAD CURRENT (A)
0.7
0.8
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Figure 1. DC1730A Efficiency: VIN = 12V, VOUT = 5V, 600kHz
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DEMO MANUAL DC1730A
QUICK START PROCEDURE
Demonstration circuit 1730A is easy to set up to evaluate the performance of the LT3973. Refer to Figure 2 for
proper measurement equipment setup and follow the
procedure below:
1. Place Jumper JP1 in the ON position.
2. With power off, connect the input power supply to VIN
and GND.
3. With power off, connect load from VOUT to GND.
4. Turn on the power at the input.
NOTE. Make sure that the input voltage does not exceed
42V.
5. Check for the proper output voltage.
NOTE. If there is no output, temporarily disconnect the
load to make sure that the load is not set too high or
is shorted.
6. Once the proper output voltages are established, adjust
the loads within the operating range and observe the
output voltage regulation, ripple voltage, efficiency and
other parameters.
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DEMO MANUAL DC1730A
QUICK START PROCEDURE
Figure 2. DC1730A Proper Measurement Equipment Setup
GND
VIN
Figure 3. Measuring Input or Output Ripple
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DEMO MANUAL DC1730A
PARTS LIST
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
REQUIRED CIRCUIT COMPONENTS
1
1
C1
CAP., X5R 22μF 6.3V 20% 1206
TAIYO YUDEN JMK316BJ226ML-T
2
1
C2
CAP., X5R 0.22μF 10V 20% 0402
AVX, 0402ZD224MAT2A
3
1
C3
CAP., X7R 2.2μF 50V 10% 1206
MURATA, GRM31CR71H225KA88L
4
1
C5
CAP., NPO, 10pF, 25V, 10%, 0402
AVX, 04023A100KAT2A
5
1
L1
IND, 15μH
COOPER/COILTRONICS, MPI4040R3-150-R
6
1
R1
RES., CHIP, 1.00M, 1/16W, 1%, 0402
NIC, NRC04F1004TRF
7
1
R2
RES., CHIP, 316k, 1/16W, 1%, 0402
NIC, NRC04F3163TRF
8
1
R5
RES., CHIP, 215k, 1/16W, 1%, 0402
NIC, NRC04F2153TRF
9
1
R9
RES., CHIP, 200k, 1/16W, 5%, 0402
NIC, NRC04J204TRF
10
1
U1
I.C., Buck Reg. MSE10
LINEAR TECH., LT3973EMSE
ADDITIONAL DEMO BOARD CIRCUIT COMPONENTS
1
1
C4
CAP., ALUMINUM EL. 10μF, 50V
2
0
R7-R8
RES., 0402
SUN ELECT, 50CE10BSS
HARDWARE FOR DEMO BOARD ONLY
1
6
E1-E6
TURRET, 0.094"
MILL-MAX, 2501-2-00-80-00-00-07-0
2
3
1
JP1
JMP, 1X3-079
WÜRTH, 62000311121
1
SHUNT
SHUNT, 2mm Ctrs.
WÜRTH, 60800213421
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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.
A
B
C
E5
E6
OFF
ON
SUNCON
50CE10BSS
+ C4
10uF
50V
VIN
JP1
1
2
3
C3
2.2uF
50V
1206
R8
OPT
R7
OPT
5
1. ALL RESISTORS ARE IN OHMS, 0402.
ALL CAPACITORS ARE IN MICROFARADS, 0402.
NOTES: UNLESS OTHERWISE SPECIFIED
EN/UVLO
PG
GND
E4
VIN E3
5.6V - 42V
GND
OUT
EN/UVLO
PG
VIN
CUSTOMER NOTICE
R9
200K
5
2
3
9
4
RT
FB
BD
BOOST
SW
U1
LT3973EMSE
3
4
3
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
L1
15uH
R5
215k
1%
(600kHz)
SCALE = NONE
JAINO P.
KIM T.
_
ECO
2
C5
10pF
C1
22uF
6.3V
1206
VOUT
E2
E1
JAINO P.
DATE
09-06-11
GND
VOUT
5V / 750mA
APPROVED
1
DATE:
N/A
SIZE
IC NO.
DEMO CIRCUIT 1730A
2
09/06/2011, 10:10 AM
LT3973EMSE
1
SHEET 1
OF 1
2
REV.
42V, 750mA, MICROPOWER BUCK REGULATOR
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900 www.linear.com
Fax: (408)434-0507
LTC Confidential-For Customer Use Only
PRODUCTION
DESCRIPTION
REVISION HISTORY
TECHNOLOGY
R2
316k
1%
R1
1.00M
1%
REV
2
TITLE: SCHEMATIC
C2
0.22uF
APPROVALS
10
1
8
7
6
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A
CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;
HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO PCB DES.
VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL
APP ENG.
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
4
GND
11
D
5
A
B
C
D
DEMO MANUAL DC1730A
SCHEMATIC DIAGRAM
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DEMO MANUAL DC1730A
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
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Linear Technology Corporation
LT 0911 • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507 ● www.linear.com
© LINEAR TECHNOLOGY CORPORATION 2011
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