DC1749B - Demo Manual

DEMO MANUAL DC1749B
LT8610
42V, 2.5A Micropower Synchronous
Step-Down Regulator
Description
Demonstration circuit 1749B is a 42V, 2.5A micropower
synchronous step-down regulator featuring the LT®8610.
The LT8610 is a compact, high efficiency, high speed
synchronous monolithic step-down switching regulator
that consumes only 2.5µA of quiescent current when
output is regulated at 5V. Top and bottom power switches,
compensation components and other necessary circuits
are inside of the LT8610 to minimize external components
and simplify design.
The demo board has an EMI filter installed. The EMI performance of the board is shown on Figure 2. The limit in
Figure 2 is EN55022 class B, average. It shows the circuit
passes the test with a wide margin.
The SYNC pin on the demo board is grounded by default
for low ripple Burst Mode® operation. To synchronous to
an external clock, move JP1 to SYNC and apply the external
clock to the SYNC turret. Once JP1 is on SYNC position,
a DC voltage of higher than 2V or INTVCC can be applied
Design files for this circuit board are available at
http://www.linear.com/demo/DC1749B
The LT8610 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 demo circuit 1749B.
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.
70
95
60
90
50
85
40
80
30
75
20
10
70
0
65
60
MKR1 2.003MHz
21.69 dBµV
10 dB/DIV
80
100
EFFICIENCY (%)
to the SYNC turret for pulse-skipping operation. Figure 1
shows the efficiency of the circuit at 12V input.
–10
0
0.5
1.5
1
LOAD CURRENT (A)
2
2.5
dc1749b F01
Figure 1. LT8610 12VIN to 5VOUT Efficiency at 2MHz
Switching Frequency
START 150kHz
RES BW (CISPR) 9kHz
VBW 62kHz
STOP 30MHz
SWEEP 717ms (6637 PTS)
dc1749b F02
Figure 2. LT8610 Demo Circuit EMI Performance,
Switching Frequency = 2MHz
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DEMO MANUAL DC1749B
Performance Summary
Specifications are at TA = 25°C
SYMBOL
PARAMETER
CONDITIONS
MIN
VIN
Input Supply Range
5.5
VOUT
Output Voltage
4.8
IOUT
Maximum Output Current
2.5
FSW
Switching Frequency
1.85
EFE
Efficiency at DC
IOUT = 1A
TYP
5
MAX
UNITS
42
V
5.2
V
A
2
2.15
MHz
92
%
Quick Start Procedure
Demonstration circuit 1749B is easy to set up to evaluate the performance of the LT8610. Refer to Figure 3 and
Figure 4 for proper measurement equipment setup and
follow the procedure below:
2.With power off, connect the load VOUT and GND.
1.With power off, connect the input power supply to VIN
and GND.
5.Carefully evaluate other design parameters as needed.
3.Check JP1 setting
4.Turn on the power at the input.
DC1749b F03
Figure 3. Proper Measurement Equipment Setup
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DEMO MANUAL DC1749B
Quick Start Procedure
DC1749b F04
Figure 4. Measure Output Ripple
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DEMO MANUAL DC1749B
Parts List
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
Required Circuit Components
1
1
C2
CAP, X7R, 4.7µF, 50V, 10%, 1206
MURATA, GRM31CR71H475KA12L
2
1
C4
CAP, X7R, 0.22µF, 16V, 10%, 0603
AVX, 0603YC224KAT2A
3
1
C5
CAP, C0G, 10pF, 25V, 10%, 0402
AVX, 04023A100KAT2A
4
1
C6
CAP, X7R, 47µF, 10V, 10%, 1210
MURATA, GRM32ER71A476KE20L
5
1
C7
CAP, X7R, 1µF, 25V, 10%, 0603
MURATA, GRM188R71E105KA12D
6
1
C8
CAP, X7R, 0.1µF, 16V, 10%, 0402
MURATA, GRM155R71C104KA88D
7
1
L1
IND, 2.2UH
COILCRAFT, XAL5030-222MEC
8
1
R2
RES, CHIP, 18.2k, 1/10W, 1%, 0603
VISHAY, CRCW060318K2FKED
9
1
R3
RES, CHIP, 49.9k, 1/16W, 1%, 0402
VISHAY, CRCW040249K9FKED
10
2
R1, R4
RES, CHIP, 1M, 1/16W, 1%, 0402
VISHAY, CRCW04021M00FKED
11
1
R5
RES, CHIP, 243k, 1/16W, 1%, 0402
VISHAY, CRCW0402243KFKED
12
1
U1
IC, LT8610EMSE, MSE16
LINEAR TECHNOLOGY CORPORATION, LT8610EMSE
CAP, ALUM, 22µF, 63V
SUN ELECT, 63CE22BS
Additional Demo Board Circuit Components
1
1
C1
2
2
C3, C10
CAP, X7R, 4.7µF, 50V, 10%, 1206
MURATA, GRM31CR71H475KA12L
3
1
C9
CAP, X7R, 4.7µF, 16V, 10%, 0805
MURATA, GRM21BR71C475K73L
4
1
C11
CAP, X7R, 1µF, 50V, 10%, 0805
TDK, C2012X7R1H105K
5
2
C12, C13
CAP, X7R, 0.1µF, 50V, 10%, 0402
TDK, C1005X7R1H104K
6
1
FB1
FERRITE BEAD, 0805
TDK, MPZ2012S221A
7
1
L2
IND 4.7UH
VISHAY, IHLP2020BZ-ER4R7M01
8
0
R6
RES, OPT, 0402
OPT
Hardware: For Demo Board Only
1
9
E1 TO E9
TESTPOINT, TURRET, 0.094"
MILL-MAX, 2501-2-00-80-00-00-07-0
2
1
JP1
HEADER 1X3 079
SAMTEC, TMM-103-02-L-S
3
1
XJP1
SHUNT, 0.079" CENTER
SAMTEC, 2SN-BK-G
4
4
MH1 TO MH4
STAND-OFF, NYLON 0.50" TALL
KEYSTONE, 8833 (SNAP ON)
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DEMO MANUAL DC1749B
Schematic Diagram
dc1749bfa
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.
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DEMO MANUAL DC1749B
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 1113 REV A • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507 ● www.linear.com
 LINEAR TECHNOLOGY CORPORATION 2012
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