DC2012A - Demo Manual

DEMO MANUAL DC2012A
LT8610AB
42V, 3.5A Micropower Synchronous
Step-Down Regulator
Description
Demonstration circuit 2012A is a 42V, 3.5A micropower synchronous step-down regulator featuring the
LT®8610AB. The LT8610AB 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. The efficiency of the circuit
is greater than 90% at light load up to 1.5A. This is a 10%
improvement over competing parts. Top and bottom power
switches, compensation components and other necessary
circuits are inside of the LT8610AB to minimize external
components and simplify design.
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
to the SYNC turret for pulse-skipping operation. Figure 1
shows the efficiency of the circuit at 12V input.
Figure 2 shows the thermal performance of the circuit.
When running at input voltage greater than 30V, 3.5A
output current and 2MHz switching frequency, the temperature rise will be significant. Either reducing the input
voltage, the output current or the switching frequency will
bring the temperature down to acceptable level without
external cooling.
The demo board has an EMI filter installed. The board
and the IC are designed to minimize conducted and radiated EMI. The conducted EMI performance of the board
is shown on Figure 3. The limit in Figure 3 is EN55022
class B, average. It shows the circuit passes the test with
a wide margin.
The LT8610AB 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 DC2012A.
Design files for this circuit board are available at
http://www.linear.com/demo/DC2012A
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
Specifications are at TA = 25°C
SYMBOL
PARAMETER
CONDITIONS
VIN*
Input Supply Range
5.5
VOUT
Output Voltage
4.8
IOUT
Maximum Output Current
3.5
fSW
Switching Frequency
EFE
Efficiency at DC
MIN
1.85
IOUT = 1A
TYP
MAX
UNITS
42
V
5
5.2
V
A
2
2.15
91
MHz
%
* Refer to Figure 2 to determine the maximum input voltage. If IC temperature exceeds target, reduce input voltage, output current or switching
frequency.
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DEMO MANUAL DC2012A
Quick Start Procedure
DC2012A is easy to set up to evaluate the performance of
the LT8610AB. Refer to Figure 4 and Figure 5 for proper
measurement equipment setup and follow the procedure
below:
1.With power off, connect the input power supply to VIN
and GND.
2.With power off, connect the load VOUT and GND.
3.Check JP1 setting
4.Turn on the power at the input.
5.Carefully evaluate other design parameters as needed.
140
95
120
CASE TEMPERATURE RISE (°C)
100
EFFICIENCY (%)
90
85
80
75
70
100
65
60
0
0.01
0.1
1
LOAD CURRENT (A)
60
40
700kHz, 3.5A
20
0
10
2MHz, 3.5A
80
2MHz, 2.5A
6
11
16
DC2012A F01
Figure 1. LT8610AB 12VIN to 5VOUT Efficiency at
2MHz Switching Frequency
21
VIN (V)
26
31
36
DC2012A F02
Figure 2. LT8610AB Case Temperature Rise.
VOUT = 5V, TA = 25°C
70
60
50
EN55022 CLASS B
40
dBµV
30
20
10
0
–10
–20
–30
START 150kHz
RES BW 9kHz
VBW 62kHz
STOP 30MHz
DC2012A F03
Figure 3. LT8610AB Demo Circuit Conducted EMI Performance
2
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DEMO MANUAL DC2012A
Quick Start Procedure
Figure 4. Proper Measurement Equipment Setup
Figure 5. Measure Output Ripple
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DEMO MANUAL DC2012A
Parts List
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
Required Circuit Components
1
1
C2
CAP., X7R, 2.2µF, 50V, 10%, 1206
MURATA, GCJ31CR71H225KA12L
2
1
C4
CAP., X7R, 0.22µF, 16V, 10%, 0603
AVX, 0603YC224KAT2A
3
1
C5
CAP., C0G, 10pF, 25V, 10%, 0402
AVX, 04023A100KAT2A
4
2
C6, C14
CAP., X7R, 47µF, 10V, 10%, 1210
MURATA, GRM32ER71A476KE15L
5
1
C7
CAP., X7R, 1.0µF, 25V, 10%, 0603
MURATA, GRM188R71E105KA12D
6
1
C8
CAP., X7R, 0.1µF, 16V, 10%, 0402
MURATA, GRM155R71C104KA88D
7
1
L1
IND., 2.2µH
COILCRAFT, XAL5030-222MEC
8
1
R2
RES., CHIP, 18.2k, 1/10W, 1% 0603
VISHAY, CRCW060318K2FKEA
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, LT8610ABEMSE#PBF MSE16
LINEAR TECH, LT8610ABEMSE#PBF
Additional Demo Board Circuit Components
1
1
C1
CAP., ALUM, 22µF, 63V
SUN ELECT, 63CE22BS
2
2
C3, C10
CAP., X7R, 4.7µF, 50V, 10%, 1206
MURATA, GRM31CR71H475KA12L
3
1
C9
CAP., X7R, 1.0µF, 16V, 10%, 0805
AVX, 0805YC105KAT2A
4
1
C11, C12
CAP., X7R, 0.1µF, 50V, 10%, 0402
TDK, C1005X7R1H104K
5
2
C13
CAP., X7R, 0.1µF, 50V, 10%, 0603
MURATA, GCJ188R71H104KA12D
6
1
FB1
FERRITE BEAD 0805
TDK, MPZ2012S101AT
7
1
L2
IND., 4.7µH
VISHAY, IHLP2020BZ-ER4R7M01
8
0
R6
RES., OPT, 0402
OPT
Hardware: For Demo Board Only
1
9
E1-E9
TESTPOINT, TURRET, .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, .079" CENTER
SAMTEC, 2SN-BK-G
4
4
MH1-MH4
STAND-OFF, NYLON 0.50" TALL
KEYSTONE, 8833(SNAP ON)
4
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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
GND
*
VIN
5.5V - 42V
E2
E1
5
E7
E9
E5
E6
C12
0.1uF
50V
C3
4.7uF
50V
1206
GND
SYNC
JP1
C10
4.7uF
50V
1206
L2
4.7uH
3
2
1
+ C1
22uF
63V
SUNCON
63CE22BS
4
* REFER TO THE DEMO MANUAL FOR VIN RANGE.
1. ALL RESISTORS ARE 0402.
ALL CAPACITORS ARE 0402.
NOTES: UNLESS OTHERWISE SPECIFIED
TR/SS
GND
SYNC
EN/UV
C11
0.1uF
50V
FB1
4
C7
1uF
0603
25V
C2
2.2uF
50V
1206
C8
0.1uF
C13
0.1uF
50V
0603
R2
18.2k
(2MHz)
0603
R6
OPT
R1
1M
3
8
7
3
2
13
1
4
6
5
3
GND
PGND
RT
TR/SS
INTVCC
SYNC
EN/UV
VIN
VIN
FB
PG
BIAS
SW
SW
SW
BST
U1
LT8610ABEMSE
GND
17
D
5
16
15
14
11
10
9
12
2
R5
243k
C4
0.22uF
16V
0603
2
C5
49.9k
R3
10pF
1Meg
R4
XAL5030-222MEC
L1
2.2uH
C14
47uF
10V
1210
C6
47uF
10V
1210
VOUT
1
1
C9
1uF
16V
0805
E8
E4
E3
PG
GND
VOUT
5V / 3.5A
A
B
C
D
DEMO MANUAL DC2012A
Schematic Diagram
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DEMO MANUAL DC2012A
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 • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507 ● www.linear.com
 LINEAR TECHNOLOGY CORPORATION 2013
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