DC2110A - Demo Manual

DEMO MANUAL DC2110A
LT8631
100V, 1A Synchronous
Micropower Step-Down Regulator
Description
Demonstration circuit 2110A is a monolithic step-down
converter featuring LT®8631. The demo board is designed
for 5V output from a 6.5V to 100V input at 400kHz switching frequency. The wide input range makes it suitable for
regulating power from a wide variety of sources, including automotive, industrial systems and telecom supplies.
The LT8631 is a compact, high efficiency synchronous
monolithic step-down switching regulator. The power
switch, compensation and other necessary circuits are
inside of the LT8631 to minimize external components
and simplify design.
The LT8631 switching frequency can be programmed
either via oscillator resistor or external clock over a
100kHz to 1MHz range. The SYNC pin on the demo board
is grounded (JP1 at Burst Mode® position) by default for
low ripple Burst Mode operation. To synchronize to an
external clock, move JP1 to SYNC and apply the external
clock to the SYNC turret. If the pulse-skipping operation
is required, move JP1 to fixed frequency position. Figure 1
shows the efficiency of the circuit at 12V input at the Burst
Mode selection.
The demo board has an EMI filter installed. The EMI performance of the board (with EMI filter) is shown in Figure
2. The red line in Figure 2 is CISPR25 Class 5 peak limit.
The figure shows that the circuit passes the test with a
wide margin. To achieve EMI/EMC performance as shown
95
90
EFFICIENCY (%)
85
80
75
70
65
60
fSW = 400kHz
VIN = 12V
VOUT = 5V
55
50
0
0.1
0.2
0.3 0.4 0.5 0.6 0.7
LOAD CURRENT (A)
0.8 0.9
1
DC2110a F01
Figure 1. LT8631 Efficiency vs Load Current
in Figure 2, the input EMI filter is required and the input
voltage should be applied at VEMI turret pin, not VIN.
The LT8631 data sheet gives a complete description of
the part, operation and application information. The data
sheet must be read in conjunction with this demo manual
for demo circuit 2110A. The LT8631 is assembled in a
20-lead TSSOP packages. Proper board layout is essential
for maximum thermal and electrical performance. See the
data sheet sections for details.
Design files for this circuit board are available at
http://www.linear.com/demo/DC2110A
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.
Performance Summary
Specifications are at TA = 25°C
SYMBOL
PARAMETER
CONDITIONS
VIN
Input Supply Range
6.5
100
V
VOUT
Output Voltage
4.88
5.04
5.2
V
fSW
Switching Frequency
RT = 25.5kΩ
370
400
430
kHz
IOUT
Max Output Current
VIN = 12V
EFE
Efficiency at DC
VIN = 12V, IOUT = 1A
82.6
%
VIN = 12V, IOUT = 0.4A
89.5
%
MIN
TYP
1
MAX
UNITS
A
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DEMO MANUAL DC2110A
Quick Start Procedure
Demonstration circuit 2110A is easy to set up to evaluate the performance of the LT8631. Refer to Figure 3 for
proper measurement equipment setup and follow the
procedure below:
4.Turn on the power at the input.
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 the proper
scope technique.
NOTE. If there is no output, temporarily disconnect the
load to make sure that the load is not set too high or is
shorted.
1.Place JP1 on GND position.
2.With power off, connect the input power supply to VEMI
and GND. If the EMI/EMC performance is not important,
the input EMI filter can be bypassed by connecting the
input power supply to VIN and GND.
3.With power off, connect loads from VOUT to GND.
5.Check for the proper output voltages (VOUT = 5V).
6.Once the proper output voltage is established, adjust
the load within the operating ranges and observe the
output voltage regulation, ripple voltage, efficiency and
other parameters.
7.An external clock can be added to the SYNC terminal
when SYNC function is used (JP1 on the SYNC position). Please ensure that the chosen RT sets the LT8631
switching frequency to 10% below the lowest SYNC
frequency. See the data sheet Synchronization section
for details.
Detector: +Peak
Polarity: Vertical
Amplitude (dBuV/m)
Am
Amplitude (dBuV/m)
50
45
40
35
30
25
20
15
10
5
0
-5
Make sure that the input voltage does not exceed 100V.
Data
Class 5
Peak
0
100
200
Detector: +Peak
Polarity:
Horizontal
50
45
40
35
30
25
20
15
10
5
0
-5
0
100
200
300
400
500
600
Frequency (MHz)
700
800
900
1000
Data
Class 5
Peak
300
400
500
600
Frequency (MHz)
700
800
900
1000
Figure 2. LT8631 Demo Circuit DC2110A EMI Performance in CISPR25 Radiated Emission Test
(14V Input from VEMI Turret Pin, IOUT = 1A)
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DEMO MANUAL DC2110A
Quick Start Procedure
–
POWER
SUPPLY
IIN
A
+
–
–
+
+
V VIN
+
+
IOUT
A
V VOUT
–
–
+
LOAD
–
Figure 3. Proper Measurement Equipment Setup
VOUT
GND
Figure 4. Measurement Input or Output Ripple
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DEMO MANUAL DC2110A
Parts List
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
Required Circuit Components
1
1
C1
CAP, 0.1µF, X7R, 10V, 10% 0402
TDK, C1005X7R1A104K
2
1
C5
CAP, 2.2µF, X5R, 10V, 10% 0402
TDK, C1005X5R1A225K050BC
3
1
C6
CAP, 4.7pF, C0G, 50V, 0.25pF 0603
MURATA, GRM1885C1H4R7CA01D
4
1
C7
CAP, 47µF, X7R, 10V, 20% 1210
MURATA, GRM32ER71A476KE15L
5
1
C8
CAP, 0.1µF, X7R, 10V, 10% 0603
AVX, 0603ZC104KAT2A
6
1
C4
CAP, 1µF, X7R, 10V, 10% 0603
SAMSUNG, CL10B105KP8NNNC
7
1
L1
INDUCTOR, 22µH IHLP2525
VISHAY, IHLP2525CZER220M11
8
1
L2
INDUCTOR, 2.2µH
COILCRAFT, XFL4020-222MEB
9
1
R1
RES, 51.1k, 1/10W, 1% 0603
VISHAY, CRCW060351K1FKEA
10
2
R2, R4
RES, 1M, 1/10W, 1% 0603
VISHAY, CRCW06031M00FKEA
11
1
R3
RES, 25.5k, 1/10W, 1% 0603
VISHAY, CRCW060325K5FKEA
12
1
R5
RES, CHIP, 191k, 1/10W, 1% 0603
VISHAY, CRCW0603191KFKEA
13
1
U1
IC, BUCK REG FE-20(16) CB
LINEAR TECHNOLOGY, LT8631EFE#PBF
SUN ELECTRONIC, 100CE10BS
Additional Demo Board Circuit Components
1
1
C2
CAP, ALUM, 10µF, 100V
2
0
C11 (OPT)
CAP, 0603
3
0
D1 (OPT)
SCHOTTKY BARRIER REC, POWER-DI-123
Hardware: For Demo Board Only
1
10
E1 TO E10
TEST POINT, TURRET, 0.094" MTG.HOLE
MILL-MAX, 2501-2-00-80-00-00-07-0
2
1
JP1
4 PIN 0.079 SINGLE ROW HEADER
SULLIN, NRPN041PAEN-RC
3
1
XJP1
SHUNT, 0.079" CENTER
SAMTEC, 2SN-BK-G
4
0
R6 (OPT)
RES, 0603
5
4
MH1 TO MH4
STAND-OFF, NYLON 0.50"
KEYSTONE, 8833 (SNAP ON)
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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.
1
2
3
4
E9
E8
E10
E4
E3
E2
C9
2.2uF
100V
1210
L2
2.2uH
R6
OPT
R4
1M
XFL4020-222ME
C3
2.2uF
100V
1210
C10
2.2uF
100V
1210
100CE10BS
C2
+
10uF
100V
VIN
VIN
R3
25.5K
(400kHz)
B
A
1. ALL RESISTORS ARE 0603.
ALL CAPACITORS ARE 0603.
B
NOTE: UNLESS OTHERWISE SPECIFIED
GND
VEMI
TR/SS
EN/UV
GND
VIN
6.5V - 100V
A
C8
0.1uF
10
9
8
7
6
5
3
1
C11
0.1uF
100V
4
3
2
1
R5
191k
1%
R2
1M
1%
C5
2.2uF
10V
0402
C1
0.1uF
0402
10V
C
DATE:
N/A
SIZE
C4
1uF
10V
R1
51.1k
SYNC
GND
VOUT
5V / 1A
PG
D
Tuesday, July 07, 2015
E
SHEET
1
OF
1
3
REV.
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900 www.linear.com
Fax: (408)434-0507
LTC Confidential-For Customer Use Only
E7
E6
E5
E1
E
100V 1A SYNCHRONOUS
MICROPOWER BUCK REGULATOR
IC NO.
LT8631EFE
DEMO CIRCUIT 2110A
TECHNOLOGY
C7
47uF
10V
1210
TITLE: SCHEMATIC
C6
4.7pF
D1
DFLS1100
OPT
D
L1
22uH
IHLP2525CZER220M11
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
CUSTOMER NOTICE
JP1
11
12
13
14
15
16
18
20
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A
CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;
HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO
VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
SYNC
BURST MODE
FIXED FREQ
21
FB
NC
TR/SS
NC
VOUT
RT
NC
IND
INTVCC
SYNC/MODE
GND
SW
BST
NC
PG
EN/UV
VIN
U1
LT8631EFE
C
1
2
3
4
DEMO MANUAL DC2110A
Schematic Diagram
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DEMO MANUAL DC2110A
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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6
Linear Technology Corporation
LT 0915 • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507 ● www.linear.com
© LINEAR TECHNOLOGY CORPORATION 2015
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