DC1787A - Demo Manual

DEMO MANUAL DC1787A
LT3759
Wide Input Voltage Range
Boost/SEPIC/Inverting Controller
DESCRIPTION
Demonstration circuit 1787A is a wide input voltage
range SEPIC converter featuring the LT3759 controller. It
converts a 2.8V~36V input to a 12V output, with 1A load
current capability for VIN ≥ 4V. The converter operates at
a 300 kHz nominal switching frequency, with 91% peak
efficiency. The DC1787A can be easily modified to generate other output voltages, and can also be optimized for
efficiency and size with narrower input voltage ranges.
The LT3759 is a boost/SEPIC/Inverting controller with a
wide input voltage range, suitable for applications from
single-cell lithium-ion battery portable electronics to high
voltage automotive and industrial power supplies. It also
exhibits low shutdown quiescent current of 1μA, making it
an ideal fit for battery-operated systems. Thanks to a novel
PERFORMANCE SUMMARY
PARAMETER
FBX pin architecture, the LT3759 can be connected directly
to a divider from either positive output or negative output
voltage to ground. It also packs many popular features
such as soft-start, input undervoltage lockout, adjustable
frequency and synchronization in a small 12-lead exposed
pad MSOP package.
The LT3759 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 demo circuit 1787A.
Design files for this circuit board are available at
http://www.linear.com/demo
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.
(TA = 25°C)
CONDITIONS
Input Voltage Range, VIN
MIN
TYP
2.8
12
Minimum Startup Voltage
MAX
UNITS
36
V
3.0
V
Switching Frequency
IOUT = 0.5A
300
Output Voltage, VOUT
VIN = 2.8V~36V
IOUT = 0mA~0.5A
Maximum Continuous Output Current, IOUT
VIN ≥ 2.8V
0.5
A
VIN ≥ 4.0V
1
A
11.64
12.0
kHz
12.36
V
Output Voltage Ripple (Peak-to-Peak)
VIN = 12V, IOUT = 1A
90
mV
Typical Efficiency
VIN = 12V, IOUT = 1A
91
%
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DEMO MANUAL DC1787A
QUICK START PROCEDURE
Demo circuit 1787A is easy to set up to evaluate the
performance of the LT3759. Refer to Figure 1 for proper
measurement equipment setup and follow the procedure.
1. With power off, connect the input power supply to the
VIN (E1) and GND (E2) terminals on the demo circuit.
NOTE: Minimize the voltage drop and transient on the
input wires between the power supply and input terminals
of the demo circuit.
2. Connect load to the VOUT (E6) and GND (E5) terminals
on the demo circuit. Connect voltage and current meters
as shown in Figure 1. Preset the load to 0.5A or less,
and VIN supply to be 0V.
3. Place jumpers in the following positions for a typical
12V application:
EN (JP1)
ON
SYNC (JP2)
OFF
4. Turn on the power supply at the input. Slowly increase
VIN to 3.0V.
NOTE: Make sure the input voltage is within the range. If
higher operating voltage is required, power components
with higher voltage ratings should be used. The maximum
input voltage of LT3759 is 42V.
NOTE: The demo circuit configures the shutdown voltage
at typical 2.5V, which means that the input voltage can be
dropped to as low as 2.5V, once it starts up. The startup
voltage is 3.0V but can be adjusted by changing R1 and
R3 values.
5. Check for the proper output voltages. The output should
be regulated at 12V (±3%).
NOTE: If there is no output, or output is out of spec, temporarily disconnect the load from the demo board. Make
sure the load current is set within spec, and the power
supply current capability is above 4A.
6. Once the proper output voltage is established, adjust the
input and load within the operating range and observe
the output voltage regulation, ripple voltage, efficiency
and other parameters. Typical efficiency curve, regulation, and operation waveforms are shown in Figures 3
and 4, respectively.
NOTE: When measuring the input or output voltage ripples,
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
and GND, or VOUT and GND terminals. See Figure 2 for
proper scope probe technique.
NOTE: The output current capability depends on the input
voltage, as can be seen in Figure 3. Proper cooling is
necessary for overload operations.
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DEMO MANUAL DC1787A
QUICK START PROCEDURE
dc1787af F01
Figure 1. Proper Measurement Equipment Setup
INPUT OR OUTPUT CAPACITOR
dc1787af F02
Figure 2. Proper Scope Probe Placement for
Measuring Input or Output Ripple
95
EFFICIENCY (%)
90
VO: 10V/DIV
85
VDS: 50V/DIV
80
75
ISW: 5A/DIV
VIN = 2.8V
VIN = 4V
VIN = 12V
70
100 200 300 400 500 600 700 800 900 1000
LOAD CURRENT (mA)
dc1787af F04
dc1787af F03
Figure 3. Efficiency Curves
Figure 4. Short Circuit Waveforms with Frequency Foldback
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DEMO MANUAL DC1787A
PARTS LIST
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
Required Circuit Components
1
2
CIN1, CIN2
CAP., X7R, 10μF, 50V, 10%, 1210
MURATA, GRM32ER71H106KA12L
2
1
CIN3
CAP., ELECT., 22μF, 50V, C-CE-BS-6.3X6.0
SUN ELECT., 50CE22BS
3
2
COUT1, COUT2
CAP., X5R, 47μF, 16V, 10%, 1210
MURATA, GRM32ER61C476KE15L
4
1
C1
CAP., X7R, 4.7μF, 50V, 20%, 1210
MURATA, GRM32ER71H475KA88L
5
1
C2
CAP., X7R, 1μF, 50V 10%, 0805
MURATA, GRM21BR71H105KA12L
6
1
C3
CAP., X5R, 4.7μF, 16V, 10%, 0805
MURATA, GRM219R61C475KE15D
7
1
C5
CAP., X7R, 68nF, 50V, 0603
NIC, NMC0603X7R682K50F
8
1
C6
CAP., X7R, 0.1μF, 25V, 10%, 0603
TDK, C1608X7R1E104K
9
1
C7
CAP., C0G, 470pF, 50V, 5%, 0603
MURATA, GCM1885C1H471JA16D
10
1
D3
DIODE, SCHOTTKY, 3A, POWERDI5
DIODES/ZETEX, PDS360-13
11
1
L1
IND, 15μH, L-DUAL-DRQ127
COILTRONICS, DRQ127-150-R
12
1
Q1
MOSFET, N-CHANNEL, LFPAK
RENESAS, RJK0652DPB-00-J5
13
1
RCS
RES SENSE, 0.005Ω, 1/2W, 1%, 2010
VISHAY, WSL20105L000FEA
14
1
RFBB
RES., CHIP, 15.8k, 1/16W, 1%, 0603
VISHAY, CRCW060315K8FKEA
15
1
RFBS
RES., CHIP, 102k, 1/16W, 1%, 0603
VISHAY, CRCW0603102KFKEA
16
1
R1
RES., CHIP, 249k, 1/16W, 1%, 0603
VISHAY, CRCW0603249KFKEA
17
1
R2
RES., CHIP, 100k, 1/16W, 5%, 0603
VISHAY, CRCW0603100KJNEA
18
1
R3
RES., CHIP, 255k, 1/16W, 1%, 0603
VISHAY, CRCW0603255KFKEA
19
1
R4
RES., CHIP, 1.43k, 1/16W, 1%, 0603
VISHAY, CRCW06031K43FKEA
20
1
R5
RES., CHIP, 27.4k, 1/16W, 1%, 0603
VISHAY, CRCW060327K4FKEA
21
1
R6
RES., CHIP, 0Ω, 0603
VISHAY, CRCW06030000Z0ED
22
1
U1
I.C. LT3759EMSE, MSE12
LINEAR TECH.,LT3759EMSE
Hardware/Components (For Demo Board Only)
1
7
E1, E2, E3, E4, E5, E6, E7
TESTPOINT, TURRET, .094"
MILL-MAX, 2501-2-00-80-00-00-07-0
2
2
JP1, JP2
JMP, 3-PIN, 1 ROW .079CC
SAMTEC, TMM-103-02-L-S
3
2
SHUNTS AS SHOWN ON
ASSY DWG
SHUNT, .079" CENTER
SAMTEC, 2SN-BK-G
4
2
STENCILS BOTH SIDES
DC1787A-2
Additional Demo Board Circuit Components
1
0
D1
DIODE, FAST SWITCHING, 1N4148WT, SOD523F
OPT
dc1787af
4
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
EN/UVLO
PGOOD
GND
E1
VIN
RUN
SHDN
JP1
1
2
3
EN/UVLO
PGOOD
SUN ELECT
50CE22BS
22uF
50V
+ CIN3
CIN1
10uF
50V
1210
C6
0.1uF
CIN2
10uF
50V
1210
C7
470pF
R3
255k
R4
1.43k
C5
68nF
0805
5
2. INSTALL SHUNTS AS SHOWN.
1. ALL RESISTORS ARE IN OHMS, 0603.
ALL CAPACITORS ARE IN MICROFARADS, 0603.
4
R5
27.4k
4
1
3
9
12
11
RT
VC
SS
INTVCC
SENSE
GATE
DRIVE
7
8
10
RFBB
15.8k
RFBS
102k
+VOUT
C2
1uF
50V
0805
1
R6
0
+VOUT
OPT
4
D1
1N4148WT
2
3
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
L1B
15uH
APPROVALS
SCALE = NONE
2
3
2
1
COUT1
47uF
16V
1210
1
3
2
1
JP2
*
*
SYNC
VIN > 4V
1A
+VOUT
12V /
VIN > 2.8V
E7
E6
GND
DATE
09-30-11
0.5A
+VOUT
E5
ZHONGMING Y.
APPROVED
2
DATE:
N/A
SIZE
IC NO.
09/30/2011, 12:52 PM
LT3759EMSE
DEMO CIRCUIT 1787A
1
SHEET 1
OF 1
2
REV.
SEPIC CONVERTER WITH WIDE INPUT VOLTAGE RANGE
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900 www.linear.com
Fax: (408)434-0507
LTC Confidential-For Customer Use Only
OFF
ON
SYNC
COUT2
47uF
16V
1210
PRODUCTION
DESCRIPTION
REVISION HISTORY
TECHNOLOGY
REV
D3
PDS360
1
_
ECO
TITLE: SCHEMATIC
Q1
RJK0652DPB
1210
C1
4.7uF
50V
RCS
0.005
2010
L1A
15uH
DRQ127-150-R
3
1
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.
KIM T.
VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL
APP ENG. ZHONGMING Y.
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
CUSTOMER NOTICE
R2
100k
EN/UVLO
VIN
U1
LT3759EMSE
C3
4.7uF 16V
R1
249k
NOTES: UNLESS OTHERWISE SPECIFIED
E4
E3
E2
VIN
2.8V - 36V
3
4
2
D
4
6
PGOOD
GND
13
2
FBX
SYNC
5
5
1
2
3
5
A
B
C
D
DEMO MANUAL DC1787A
SCHEMATIC DIAGRAM
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DEMO MANUAL DC1787A
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
dc1787af
6
Linear Technology Corporation
LT 1111 • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507 ● www.linear.com
© LINEAR TECHNOLOGY CORPORATION 2011
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