Linear Technology DC1821B User manual

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dc1821bf
DEMO MANUAL DC1821B
DESCRIPTION
LTC3114EDHC-1
40V, 1A Synchronous Buck-Boost DC/DC
Converter with Output Current Limit
Demonstration circuit 1821B features the LT C
®
3114-1, a
wide operating range synchronous monolithic buck-boost
converter with programmable average output current.
The DC1821B demo board has two user selectable operat-
ing modes: Burst Mode
®
operation and Fixed Frequency
PWM (JP2). There is also an accurate programmable RUN
pin which is used to ENABLE the converter (JP1).
The LTC3114-1 uses average current mode control to
simplify voltage loop compensation and provide good line
and load transient response.
The DC1821B operates with a 2.7V to 40V input volt-
age 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.
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.
In PWM mode, the LTC3114-1 operates at 1.2MHz to
optimize small size with high efficiency operation.
The demo board also incorporates diode D1 to backfeed
VCC to improve efficiency in some applications. If the
demo board output voltage is changed to a higher volt-
age, D1 should be removed. Consult the data sheet for
more information.
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 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.
Design files for this circuit board are available at
http://www.linear.com/demo/DC1821B
PARAMETER TYP
Input Voltage Range 2.7V to 40V
VOUT 5V
IOUT (See Note 1) 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.
PERFORMANCE SUMMARY
Specifications are at TA= 25°C

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DEMO MANUAL DC1821B
Figure 2. DC1821B Input Voltage Step Response. VIN Stepped from 3.3V to 12V IOUT is 500mA
Figure 3. DC1821B Step Load Response. VIN = 12V Load Step is from 250mA to 750mA
DESCRIPTION
dc1821a F02
VOUT: 500mV/DIV
VIN: 5V/DIV
dc1821a F03
VOUT: 100mV/DIV
IOUT: 500mA/DIV
Figure 1. DC1821B Efficiency in Auto Burst Mode Operation
DC1821B Typical Efficiency in
Auto Burst Mode Operation
VIN (V)
0
EFFICIENCY (%)
100
80
90
70
60
50 10 205 15 30
dc1821a F01
40
25 35
250mA LOAD
500mA LOAD
750mA LOAD
1A LOAD

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DEMO MANUAL DC1821B
Figure 4. Proper Measurement Equipment Setup Figure 5. Measuring Input or Output Ripple
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 oscil-
loscope 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 oscil-
loscope 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 anammeter inseries with thesupply asshown.
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 volt-
age 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.
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 operation 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

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DEMO MANUAL DC1821B
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 1.0μF 25V X5R 0603 TDK, C1608X5R1E105M
5 1 C6 CAP CER 10μF 50V 20% X7R 2220 TDK, C5750X7R1H106M230KB
6 1 C8 CAP CER 1.0μF 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 0.047μF 25V 20% X7R 0402 TDK, C1005X7R1E473M050BC
10 1 D1 DIODE SCHOTTKY 20V NXP, PMEG2010AEH
11 1 D2 DIODE SCHOTTKY 60V, 2A NXP, PMEG6020ER,115
12 1 L1 INDUCTOR, 6.8μH ±30% COILCRAFT, MSS1048-682NLB
13 1 R1 RES 2.00M 1/16W 1% 0402 SMD VISHAY, CRCW04022M00FKED
14 1 R2 RES 499k 1/16W 1% 0402 SMD VISHAY, CRCW0402499KFKED
15 1 R3 RES SMD 10k 1% 1/16W 0402 VISHAY,CRCW040210K0FKED
16 1 R4 RES 27.4k 1/16W 1% 0402 SMD VISHAY, CRCW040227K4FKED
17 1 R5 RES 1.00M 1/16W 1% 0402 SMD VISHAY, CRCW04021M00FKED
18 1 R8 RES 49.9Ω 1/16W 1% 0402 SMD VISHAY, CRCW040249R9FKED
19 1 U1 40V, 1A BUCK-BOOST DC/DC CONVERTER WITH
PROGRAMMABLE OUTPUT CURRENT
LINEAR TECHNOLOGY, LTC3114MDHC-1
Additional Demo Board Circuit Components
20 0 C7 CAP 330μF 63V ELECT MVA SMD UNITED CHEMI-CON EMVA630ADA331MKG5S
21 0 C12 CAP CER 1000pF 25V X7R 0402 TDK, C1005X7R1E102M
22 0 C14 DNP
23 0 R6, R7 DNP
Hardware for Demo Board Only
24 4 E1, E2, E3, E4 TURRET, 0.09" DIA MILL-MAX, 2501-2-00-80-00-00-07-0
25 2 JP2, JP1 HEADERS, 3 PINS, 2mm CTRs SULLINS, NRPN031PAEN-RC
26 2 XJP1, XJP2 SHUNT, 2mm CTRs SAMTEC, 2SN-BK-G
27 4 STAND OFF STAND-OFF, NYLON 0.50" TALL KEYSTONE, 8832 (SNAP ON)

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DEMO MANUAL DC1821B
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 representa-
tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.
SCHEMATIC DIAGRAM
5
5
4
4
3
3
2
2
1
1
D D C C B B A A
RUN
ON
OFF BURST MODE
MODE
FIXED FREQ
GND
VOUT
VIN LDO
MODE
MODE
RUN
RUN
VIN
LDO
SIZE DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: [phone]
Milpitas, CA 95035 Phone: [phone] McCarthy Blvd. LTC Confidential-For Customer Use Only
CUSTOMER NOTICE
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. THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
SCALE = NONE
www.linear.com
1
DEMO CIRCUIT 1821B
11
WITH PROGRAMMABLE OUTPUT CURRENT
N/A
LTC3114-1EDHC
NC
J.NOON
11 - 7 - 15
40V, 1A SYNCHRONOUS BUCK - BOOST DC / DC CONVERTER
SIZE DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: [phone]
Milpitas, CA 95035 Phone: [phone] McCarthy Blvd. LTC Confidential-For Customer Use Only
CUSTOMER NOTICE
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. THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
SCALE = NONE
www.linear.com
1
DEMO CIRCUIT 1821B
11
WITH PROGRAMMABLE OUTPUT CURRENT
N/A
LTC3114-1EDHC
NC
J.NOON
11 - 7 - 15
40V, 1A SYNCHRONOUS BUCK - BOOST DC / DC CONVERTER
SIZE DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: [phone]
Milpitas, CA 95035 Phone: [phone] McCarthy Blvd. LTC Confidential-For Customer Use Only
CUSTOMER NOTICE
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. THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
SCALE = NONE
www.linear.com
1
DEMO CIRCUIT 1821B
11
WITH PROGRAMMABLE OUTPUT CURRENT
N/A
LTC3114-1EDHC
NC
J.NOON
11 - 7 - 15
40V, 1A SYNCHRONOUS BUCK - BOOST DC / DC CONVERTER
REVISION HISTORY DESCRIPTION DATEAPPROVEDECO REV
J.NOONPRODUCTION- 6-6-16
REVISION HISTORY DESCRIPTION DATEAPPROVEDECO REV
J.NOONPRODUCTION- 6-6-16
REVISION HISTORY DESCRIPTION DATEAPPROVEDECO REV
J.NOONPRODUCTION- 6-6-16
E3
VOUT
5.0V / 1A
+
C7
OPT
R1
2M 1%
C8
1uF
50V
E4
GND
E1
VIN
2.7V - 40V
C4
22uF 25V
R2
499k
1%
C6
10uF
50V
C14 DNP
C13
22uF 25V
C5
1uF 25V
R3
10k
JP2
1 2 3
D1
PMEG2010AEH
C9
4700pF
C1
68nF
R7 DNP
JP1
1 2 3
C12
DNP
R4
27.4k
D2
PMEG6020ER
L1
6.8uH
C11
47nF
E2
GND
C10
10pF
C2
68nF
R5 1M
C3
4.7uF 6.3V
U1
LTC3114-1
SW1 15
RUN
4
BST1
13
PVIN
14
VIN
10
GND
8
MODE
16
PLDO 11
GND
17
PVOUT 3
BST2 12
SW2 2
PROG
5
PGND
1
LDO 9
FB 7
VC 6
R6 DNP
R8
49.9 1%

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DEMO MANUAL DC1821B
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
[phone] ●FAX: [phone] ●www.linear.com
 LINEAR TECHNOLOGY CORPORATION 2016
LT 0716• PRINTED IN USA
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:
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1630 McCarthy Blvd.
Milpitas, CA 95035
Copyright © 2004, Linear Technology Corporation