DC1821A - Demo Manual

DEMO MANUAL DC1821A
LTC3114EDHC-1
40V, 1A Synchronous Buck-Boost DC/DC
Converter with Output Current Limit
Description
Demonstration Circuit 1821A features the LTC®3114-1, a
wide operating range synchronous monolithic buck-boost
converter with programmable average output current.
In PWM mode, the LTC3114-1 operates at 1.2MHz to
optimize small size with high efficiency operation.
The DC1821A demo board has two user selectable operating modes: Burst Mode® and Fixed Frequency PWM (JP2).
There is also an accurate programmable RUN pin which
is used to ENABLE the converter (JP1).
The demo board also incorporates diode D1 to back-feed
VCC to improve efficiency in some applications. If the
demo board output voltage is changed to a higher voltage, D1 should be removed. Consult the data sheet for
more information.
The LTC3114-1 uses average current mode control to
simplify voltage loop compensation and provide good line
and load transient response.
Figure 1 shows typical demo board efficiency. Figure 2
shows the response to an input voltage step while Figure 3
shows the load step response.
The DC1821A operates with a 2.7V to 40V input voltage range. The demo board has been designed with the
output voltage set to 5V. The LTC3114-1 incorporates a
proprietary low noise switching algorithm which optimizes
efficiency with input voltages above, below or equal to the
output voltage and ensures seamless transitions between
operating modes.
The LTC3114-1 data sheet has detailed information about
the operation, specifications, and applications of the part.
The data sheet should be read in conjunction with this
Quick Start Guide.
Performance Summary
Design files for this circuit board are available at
http://www.linear.com/demo/DC1821A
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.
Specifications are at TA = 25°C
PARAMETER
TYP
Input Voltage Range
2.7V to 40V
VOUT
IOUT (See Note 1)
5V
1A for VIN > 6V
Efficiency
See Figure 1
NOTE 1: The demo board output current is a function of VIN. Please refer to the data sheet for more information.
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DEMO MANUAL DC1821A
Description
DC1821A Typical Efficiency in
AutoBURST MODE
100
EFFICIENCY (%)
90
80
70
250mA LOAD
500mA LOAD
750mA LOAD
1A LOAD
60
50
0
5
10
15
20 25
VIN (V)
30
35
40
dc1821a F01
Figure 1. DC1821A Efficiency in AutoBURST
VOUT: 500mV/DIV
VIN: 5V/DIV
dc1821a F02
Figure 2. DC1821A Input Voltage Step Response. VIN Stepped from 3.3V to 12V IOUT is 500mA
VOUT: 100mV/DIV
IOUT: 500mA/DIV
dc1821a F03
Figure 3. DC1821A Step Load Response. VIN = 12V Load Step is from 250mA to 750mA
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DEMO MANUAL DC1821A
Quick Start Procedure
Using short twisted pair leads for any power connections
and with all loads and power supplies off, refer to Figure 4
for the proper measurement and equipment setup. The
battery/power supply (PS1) should not be connected to
the circuit until told to do so in the procedure below.
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 5), or by using an oscilloscope probe tip jack.
1. Jumper and PS1 settings to start:
PS1:
OFF
JP1:
RUN
ON
JP2:
MODE
FIXED FREQUENCY
2. With power OFF connect the power supply (PS1) as
shown in Figure 4. If accurate current measurements
are desired (for efficiency calculations for example)
connect an ammeter in series with the supply as shown.
The ammeter is not required however.
3. Connect a 500mA load to VOUT as shown in Figure 4
(10Ω for VOUT = 5V). Connect an ammeter if accurate
current measurement or monitoring is desired.
4. Turn on PS1 and slowly increase voltage until the voltage at VIN is 4V.
5. Verify VOUT is ~5V.
6. VIN can now be varied between 2.7V and 40V. IOUT
may need to be reduced for VIN < 4V VOUT should
remain in regulation.
7. Load current (IOUT) can also be varied. The maximum
IOUT is a function of VIN and the current limit. Consult
the data sheet for more information on IOUT vs VIN.
In general for VIN > 5V IOUT can be increased to 1A.
8. For operation in BURST Mode move Jumper JP2 to
BURST. See the data sheet for more information.
9. NOTE: If VOUT drops out of regulation, check to be
sure the maximum load has not been exceeded, or that
VIN is not below the minimum value for regulation (see
data sheet)
10.NOTE: If VOUT is changed to a voltage higher than
5V, D1 should be removed or the LTC3114-1 could
be damaged.
GND
VIN
Figure 4. Proper Measurement Equipment Setup
Figure 5. Measuring Input or Output Ripple
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DEMO MANUAL DC1821A
Parts List
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
Required Circuit Components
1
2
C1, C2
CAP CER 0.068µF 16V 10% X7R 0402
TDK, C1005X7R1C683K
2
1
C3
CAP CER 4.7µF 6.3V X5R 20% 0603
TDK, C1608X5R0J475M
3
2
C4, C13
CAP CER 22µF 25V X7R 20% 1812
TDK, C4532X7R1E226M
4
1
C5
CAP CER 1µF 25V X5R 0603
TDK, C1608X5R1E105M
5
1
C6
CAP CER 10µF 50V 20% X7R 2220
TDK, C5750X7R1H106M230KB
6
1
C8
CAP CER 1µF 50V X7R 20% 1206
TDK, C3216X7R1H105M
7
1
C9
CAP CER 4700pF 25V X7R 10% 0402
TDK, C1005X7R1E472K
8
1
C10
CAP CER 10pF 50V C0G 0402
TDK, C1005C0G1H100D
9
1
C11
CAP CER 10000pF 25V 20% X7R 0402
TDK, C1005X7R1E103M050BB
10
1
L1
INDUCTOR, 6.8µH ±30%
COILCRAFT, MSS1048-682NLB
11
1
R1
RES 2M 1/16W 1% 0402 SMD
VISHAY, CRCW04022M00FKED
12
1
R2
RES 499k 1/16W 1% 0402 SMD
VISHAY, CRCW0402499KFKED
13
1
R3
RES 21k 1/16W 1% 0402 SMD
VISHAY, CRCW040221K0FKED
14
1
R4
RES 27.4k 1/16W 1% 0402 SMD
VISHAY, CRCW040227K4FKED
15
1
R5
RES 1.00M 1/16W 1% 0402 SMD
VISHAY, CRCW04021M00FKED
16
1
R8
RES 49.9Ω 1/16W 1% 0402 SMD
VISHAY, CRCW040249R9FKED
17
1
U1
40V, 1A BUCK-BOOST DC/DC CONVERTER
WITH PROGRAMMABLE OUTPUT CURRENT
LINEAR TECHNOLOGY, LTC3114EDHC-1
Additional Demo Board Circuit Components
18
0
C7
CAP 330µF 63V ELECT MVA SMD
UNITED CHEMI-CON
EMVA630ADA331MKG5S
19
0
C12
CAP CER 1000pF 25V X7R 0402
TDK, C1005X7R1E102M
20
0
C14
DNP
21
0
D1
DIODE SCHOTTKY 20V
22
0
R6, R7
DNP
NXP, PMEG2010AEH
Hardware: For Demo Board Only
23
4
E1, E2, E3, E4
TURRET, 0.09" DIA
MILL-MAX, 2501-2-00-80-00-00-07-0
24
2
JP2, JP1
HEADERS, 3 PINS, 2mm CTRs
SULLINS, NRPN031PAEN-RC
25
2
XJP1, XJP2
SHUNT, 2mm CTRs
SAMTEC, 2SN-BK-G
26
4
STAND OFF
STAND-OFF, NYLON 0.50" TALL
KEYSTONE, 8832 (SNAP ON)
dc1821af
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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
VIN
OFF
ON
E2
JP1
RUN
GND
1
2
3
C6
10uF
50V
2.7V - 40V
E1
5
DNP
R6
+
R5 1M
C7
OPT
VIN
PROG
MODE
RUN
BURST MODE
FIXED FREQ
5
16
4
PVIN
VIN
BST1
CUSTOMER NOTICE
RUN
VIN
C11 R3
10nF 21k
MODE
RUN
14
10
13
JP2
MODE
1
2
3
VC
FB
LDO
PLDO
PVOUT
BST2
LTC3114-1
6.8uH
L1
4
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
3
MODE
LDO
GND
R4
27.4k
C9
4700pF
C2
68nF
3
SCALE = NONE
J.NOON
NC
APPROVALS
U1
6
7
9
11
3
12
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.
C12
DNP
C8
1uF
50V
C1
68nF
4
15
SW1
GND
8
GND
17
2
SW2
PGND
1
D
5
C10
10pF
R2
499K
1%
R1
2M
1%
R8
49.9
1%
DNP
C14
DNP
R7
C13
22uF
25V
VOUT
E4
GND
5.0V / 1A
C5
1uF
25V
E3
REV.
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900 www.linear.com
Fax: (408)434-0507
LTC Confidential-For Customer Use Only
C4
22uF
25V
1
DATE:
N/A
SIZE
2
LTC3114-1EDHC
DEMO CIRCUIT 1821A
12 - 13 - 13
IC NO.
1
SHEET
1
OF
1
3
40V, 1A SYNCHRONOUS BUCK - BOOST DC / DC CONVERTER
WITH PROGRAMMABLE OUTPUT CURRENT
TECHNOLOGY
LDO
TITLE: SCHEMATIC
C3
4.7uF
6.3V
D1
VOUT
NOTE: D1 should be removed if VOUT is >5V.
2
A
B
C
D
DEMO MANUAL DC1821A
Schematic Diagram
dc1821af
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DEMO MANUAL DC1821A
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
dc1821af
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Linear Technology Corporation
LT 0514 • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507 ● www.linear.com
 LINEAR TECHNOLOGY CORPORATION 2014
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