DC2242A - Demo Manual

DEMO MANUAL DC2242A
LT8494
SEPIC/Boost DC/DC Converter with 2A,
70V Switch, and 7µA Quiescent Current
Description
Demonstration circuit 2242A is a monolithic SEPIC converter featuring LT®8494. The demo board is designed for
5V output from a 3V to 60V input at 450kHz switching
frequency. The max output current is 1A when the input
voltage is above 12V, and is reduced with lower input voltage. The quiescent current of LT8494 is less than 7μA when
operating. Dual supply pins (VIN and BIAS) allow the part
to automatically operate from the most efficient supply.
Low ripple Burst Mode® operation increases the efficiency
at the light load while keeping the output ripple below
10mV. Figure 1 shows the demo board efficiency at 12V
input voltage. Figure 2 shows the maximum load current
with different input voltages of the demo board.
The LT8494 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
DC2242A. The LT8494 is assembled in 20-lead QFN and
20-lead plastic 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/DC2242A
L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks
of Linear Technology Corporation. All other trademarks are the property of their respective
owners.
90
MAXIMUM LOAD CURRENT (A)
2.5
EFFICIENCY (%)
80
70
60
50
40
VIN = 12V
VOUT = 5V
fSW = 450kHz
0
0.2
0.6
0.8
0.4
LOAD CURRENT (A)
2.0
1.5
1.0
0.5
0
1
0
10
30
40
20
INPUT VOLTAGE (V)
DC2242A F01
60
DC2242A F01
Figure 1. LT8494 Efficiency
Performance Summary
50
Figure 2. LT8494 Maximum Load Current
(Typical) vs Input Voltage
Specifications are at TA = 25°C
SYMBOL
PARAMETER
VIN
Input Supply Range
CONDITIONS
VOUT
Output Voltage
fSW
Switching Frequency
RT = 169kΩ
IOUT
Max Output Current
VIN = 12V
EFE
Efficiency at DC
VIN = 12V, IOUT = 1A
MIN
TYP
3
MAX
60
UNITS
V
4.86
5.04
5.24
V
414
450
477
kHz
1
A
80.3
%
dc2242af
1
DEMO MANUAL DC2242A
Quick Start Procedure
DC2242A is easy to set up to evaluate the performance
of the LT8494. Refer to Figure 3 for proper measurement
equipment setup and follow the procedure below:
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.
1.With power off, connect the input power supply to VIN
and GND. Make sure that the input voltage does not
exceed 60V.
2
2.With power off, connect loads from VOUT to GND.
3.Turn on the power at the input.
4.Check for the proper output voltages (VOUT = 5V).
NOTE: If there is no output, temporarily disconnect the
load to make sure that the load is not set too high or
is shorted.
5.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.
dc2242af
DEMO MANUAL DC2242A
Quick Start Procedure
Figure 3. Proper Measurement Equipment Setup
VOUT
GND
Figure 4. Measuring Input or Output Ripple
dc2242af
3
DEMO MANUAL DC2242A
Parts List
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
Required Circuit Components
1
2
C2, C8
CAP., X7R, 2.2µF, 100V, 10%, 1210
MURATA, GRM32ER72A225KA35L
2
2
C3, C4
CAP., X7R, 47µF, 10V, 10%, 1210
MURATA, GRM32ER71A476KE15L
3
2
C5, C7
CAP., X7R, 1µF, 10V, 10%, 0603
MURATA, GRM188R71A105KA61D
4
1
C6
CAP., NP0, 4.7pF, 50V, ±0.25pF, 0603
MURATA, GRM1885C1H4R7CA01D
5
1
D1
DIODE, SCHOTTKY 100V, 2A, SMA
ON SEMI., MBRA2H100T3G
6
1
L1
INDUCTOR, 15µH
VISHAY, IHCL4040DZER150M5A
7
2
R1, R10
RES., CHIP, 1M, 1/10W, 0603
VISHAY, CRCW06031M00FKEA
8
1
R2
RES., CHIP, 316K, 1/10W, 1%, 0603
VISHAY, CRCW0603316KFKEA
9
1
R4
RES., CHIP, 100k, 1/10W, 1%, 0603
VISHAY, CRCW0603100KFKEA
10
1
R6
RES., CHIP, 169k, 1/10W, 1%, 0603
VISHAY, CRCW0603169KFKEA
11
1
R9
RES., CHIP, 0, 1/10W, 0603
VISHAY, CRCW06030000Z0EA
12
1
U1
I.C., , LT8494, TSSOP-20-4.4mm
LINEAR TECH., LT8494EFE#PBF
Additional Demo Board Circuit Components
1
1
C1
CAP., ALUM, 10µF, 63V, 20%
SUN ELECTRONIC, 63CE10BS
2
0
C10 (OPT)
CAP., OPTION, 0603
OPT
3
0
R11 (OPT)
RES., OPTION, 0603
OPT
TESTPOINT, TURRET, .094" PBF
MILL-MAX, 2501-2-00-80-00-00-07-0
Hardware: For Demo Board Only
1
4
6
E1-E6
dc2242af
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
D
C1
10uF
63V
63CE10BS
+
C2
2.2uF
100V
1210
R11
OPT
R10
1M
5
1. ALL RESISTORS ARE IN OHMS, 0603.
ALL CAPACITORS ARE IN MICROFARADS, 0603.
4
NOTES: UNLESS OTHERWISE SPECIFIED
INPUT VOLTAGE IS LESS THAN 12V. PLEASE SEE
DEMO MANUAL FOR DETAILS.
E6
E2
E1
* THE MAX LOAD CURRENT IS REDUCED WHEN THE
SWEN
GND
VIN
3V - 60V *
4
C7
1uF
RT
SS
NC
NC
SWEN
VIN
NC
PG
NC
FB
FB
NC
BIAS
3
R9
0
C10
OPT
3
DATE:
N/A
SIZE
2
C6
4.7pF
R4
100K
1%
TECHNOLOGY
R2
316K
1%
C4
47uF
10V
1210
E5
E4
C5
1uF
10V
0603
E3
PG
GND
VOUT
5V / 1A *
LT8494EFE
DEMO CIRCUIT 2242A
2
Tuesday, May 05, 2015
IC NO.
1
SHEET
1
OF
1
1
REV.
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900 www.linear.com
Fax: (408)434-0507
LTC Confidential-For Customer Use Only
C3
47uF
10V
1210
1
SEPIC CONVERTER WITH LOW IQ
SCHEMATIC
R1
1M
1%
D1
MBRA2H100T3G
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
CUSTOMER NOTICE
13
7
15
3
2
11
1
1210
C8
2.2uF
100V
1
L1
15uH
IHCL4040DZ-5A
2
4
3
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
TITLE:
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
R6
169K
(450kHz)
10
8
6
5
12
18
U1
LT8494EFE
NC
4
NC
9
20
GND
14
SW
GND
16
GND
21
NC
17
NC
19
5
A
B
C
D
DEMO MANUAL DC2242A
Schematic Diagram
dc2242af
5
DEMO MANUAL DC2242A
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
6
dc2242af
Linear Technology Corporation
LT 0715 • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507 ● www.linear.com
 LINEAR TECHNOLOGY CORPORATION 2015
Similar pages