DC1881A - Demo Manual

DEMO MANUAL DC1881A
LTC3789EUFD
High Efficiency Compact
Buck-Boost Converter
DESCRIPTION
Demonstration circuit 1881A is a high efficiency synchronous buck-boost DC/DC converter with 6V to 36V
input range. It can supply 2.5A maximum load current at
12V output. The demo board features the LTC®3789EUFD
controller. The constant-frequency current mode architecture allows a phase-lockable frequency of up to 600kHz,
while an optional output current feedback loop provides
support for applications such as battery charging. With a
wide input range, wide output range and seamless transfers between operation modes, the LTC3789 is ideal for
automotive, telecom, distributed DC power systems and
battery-powered applications. This board has a compact
solution size with dual SO-8 MOSFETs, small inductor and
capacitor footprints. The package of LTC3789EUFD is a
small, low thermal impedance 4mm × 5mm 28-Lead QFN.
PERFORMANCE SUMMARY
PARAMETER
The light load operation mode of the converter is determined
with the MODE/PLLIN pin. Use the JP2 jumper to select
pulse skipping mode or forced continuous mode (CCM)
operation. Switching frequency is preset at about 400kHz.
The converter can also be externally synchronized through
the MODE/PLLIN pin (PLLIN terminal on the board). To
shut down the converter, one simple way is to force the
RUN pin below 1.2V (JP1: OFF). The power good output
(PGOOD terminal) is low when the output voltage is outside
of the ±10% regulation window.
Design files for this circuit board are available at
http://www.linear.com/demo
L, LT, LTC, LTM, μModule, Linear Technology and the Linear logo are registered trademarks of
Linear Technology Corporation. All other trademarks are the property of their respective owners.
Specifications are at TA = 25°C
CONDITION
Input Voltage Range
VALUE
6V to 36V
Output Voltage, VOUT
VIN = 6V to 36V, IOUT = 0A to 2.5A
Maximum Output Current, IOUT
VIN = 6V to 36V, VOUT = 12V
Typical Output Ripple
VIN = 36V, IOUT = 12A (20MHz BW)
44mVP-P
Typical Efficiency
VIN = 12V, VOUT = 12V, IOUT = 2.5A
97.2%
Typical Switching Frequency
12V ±2%
2.5A
400kHz
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DEMO MANUAL DC1881A
QUICK START PROCEDURE
Demonstration circuit 1881A is easy to set up to evaluate
the performance of the LTC3789. Refer to Figure 1 for
the proper measurement equipment setup and follow the
procedure below:
1. With power off, connect the input power supply to VIN
(6V to 36V) and GND (input return).
Note: When measuring the output or input voltage ripple,
do not use the long ground lead on the oscilloscope probe.
See Figure 2 for the proper scope probe technique. Short,
stiff leads need to be soldered to the (+) and (–) terminals
of an output capacitor. The probe’s ground ring needs to
touch the (–) lead and the probe tip needs to touch the
(+) lead.
2. Connect the 12V output load between VOUT and GND
(Initial load: no load).
Additional Notes:
3. Connect the DVMs to the input and outputs.
1. Usually, the worst case efficiency at full load is at 6VIN.
The board can deliver more output power at higher VIN.
4. Turn on the input power supply and check for the proper
output voltages. VOUT should be 12V ±2%.
2. R2 is needed for additional/constant output current
limit only.
5. Once the proper output voltages are established, adjust the loads within the operating range and observe
the output voltage regulation, ripple voltage and other
parameters.
Figure 1. Proper Measurement Equipment Setup
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DEMO MANUAL DC1881A
QUICK START PROCEDURE
+
–
COUT
VOUT
GND
Figure 2. Measuring Output Voltage Ripple
100
VIN = 12V
EFFICIENCY (%)
VIN = 24V
95
VIN = 6V
VIN = 36V
90
85
0
0.5
1.0
1.5
LOAD CURRENT (A)
2.0
2.5
DC1881 F03
Figure 3. Efficiency vs Load Current (VO = 12V, CCM)
PARTS LIST
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
Required Circuit Components
1
1
CC1
CAP., C0G, 100pF, 50V, 10% 0603
AVX, 06035A101KAT2A
2
1
CC2
CAP., X7R, 0.01μF, 50V, 10% 0603
AVX, 06035C103KAT2A
3
1
CSS
CAP., X7R, 0.1μF, 50V, 10% 0603
AVX, 06035C104KAT2A
4
1
C15
CAP., X7R, 1μF, 50V, 10% 0805
AVX, 08055C105K
5
2
C7, C8
CAP., X7R, 0.1μF, 50V, 10% 0603
AVX, 06035C104K
6
1
CF
CAP., X7R, 22pF, 50V, 10% 0603
AVX, 06035C220K
7
1
C11
CAP., NPO, 68pF, 50V, 10% 0603
AVX, 06035A680KAT2A
8
1
C10
CAP., X5R, 2.2μF, 16V, 10% 0603
TDK, C1608X5R1C225K
9
1
C24
CAP., X5R, 1μF, 16V, 10% 0603
AVX, 0603YD105KAT2A
10
4
C16, C17, C19, C20
CAP., X7R, 22μF, 16V, 20% 1210
AVX, 1210YC226MAT2A
11
2
C4, C22
CAP., X7R, 0.22μF, 16V, 20% 0603
AVX, 0603YC224MAT2A
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DEMO MANUAL DC1881A
PARTS LIST
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
12
3
C9, C25, C26
CAP., X7R, 10μF, 50V, 20% 1210
TDK, C3225X7S1H106M
13
1
C18
CAP., X5R, 10μF, 6.3V, 20% 1206
AVX, 12066D106MAT2A
14
4
D4-D7
SCHOTTKY REC., DFLS160, POWER DI-123
DIODE INC., DFLS160
15
1
D8
ZENER DIODE, 5.1V, BZX84C5V1, SOT23
DIODES INC., BZX84C5V1-7-F
16
1
L1
INDUCTOR, 5.6μH
COILCRAFT, XAL7070-562ME
17
2
Q1, Q2
DUAL N-CHANNEL MOSFET, SO-8
VISHAY, Si4288DY-T1-E3
18
1
RC
RES., CHIP, 13k, 1/10W, 1% 0603
VISHAY, CRCW060313K0FKEA
19
1
RFB1
RES., CHIP, 113k, 1/10W, 1% 0603
YAGEO, RC0603FR-07113KL
20
1
RFB2
RES., CHIP, 8.06k, 1/10W, 1% 0603
YAGEO, RC0603FR-078K06L
21
1
R18
SENSOR RES., 0.015Ω, 1W, 1%, 2512
THIN FILM TECH., RL3720WT-R015-F
22
1
R2
SENSOR RES., 0.015Ω, .25W, 1%, 1206
VISHAY, WSL1206R0150FEA
23
6
R3, R4, R9, R10, R13, R14
RES., CHIP, 100Ω, 1/10W, 1% 0603
YAGEO, RC0603FR-07100RL
24
1
R7
RES., CHIP, 100k, 1/10W, 1% 0603
YAGEO, RC0603FR-07100KL
25
1
R8
RES., CHIP, 10Ω, 1/10W, 5% 0603
YAGEO, RC0603JR-0710RL
26
1
R26
RES., CHIP, 10Ω 1/8W, 5% 0805
YAGEO, RC0805JR-0710RL
27
1
R5
RES., CHIP, 10Ω 1/8W, 5% 0805
YAGEO, RC0805JR-0710RL
28
6
R1, R11, R17, R23, R25, R27
RES., CHIP, 0Ω, 1/10W, 1% 0603
YAGEO, RC0603FR-070RL
29
1
R20
0Ω JUMPER, 1/4W, 1206
IRC
30
1
R16
RES., CHIP, 1k, 1/10W, 1% 0603
YAGEO, RC0603FR-071KL
31
1
R24
RES., CHIP, 10k, 1/10W, 1% 0603
YAGEO, RC0603FR-0710KL
32
1
R21
RES., CHIP, 121k, 1/10W, 1% 0603
YAGEO, RC0603FR-07121KL
33
1
R30
RES., CHIP, 41.2k, 1/10W, 1% 0603
YAGEO, RC0603FR-0741K2L
34
1
R31
RES., CHIP, 12.1k, 1/10W, 1% 0603
YAGEO, RC0603FR-0712K1L
35
1
U1
I.C., VOLT. REG.
LINEAR TECH. CORP. LTC3789EUFD
Additional Demo Board Circuit Components
1
0
CF1 (OPT)
CAP., 0603
2
0
COUT1 (OPT)
CAP., OS-CON, 330μF, 16V, 20%
3
0
C14, C23, C29 C35 (OPT)
CAP., 1210
4
0
C12, C13 (OPT)
CAP., 1206
5
0
R6, R12, R22 (OPT)
RES., 0603
6
0
R28, R29 (OPT)
RES., CHIP, 1206
SANYO, 16SEP330M+T
Hardware: For Demo Board Only
1
2
JP1, JP2
3-PIN 0.079" SINGLE ROW HEADER
SAMTEC, TMM103-02-L-S
2
2
XJP1, XJP2B
SHUNT, 0.079" CENTER
SAMTEC, 2SN-BK-G
3
9
TP3-TP7, TP10-TP14
TESTPOINT, TURRET, 0.094" pbf
MILL-MAX, 2501-2-00-80-00-00-07-0
4
4
(STAND-OFF)
STAND-OFF, NYLON 0.50"
KEYSTONE, 8833 (SNAP ON)
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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
D
EXTVCC
TP4
TP12
JP1
RUN
3
2
1
JP2
MODE
5
R31
12.1K
41.2K
R30
VIN+
CCM
RFB1
113K
R24
10K
D8
BZX84C5V1
3
2
1
INTVCC
CF1 OPT
RFB2 8.06K
R16 1K
CSS
0.1uF
PULSE SKIP
TP10
TP5
OFF
ON
PLLIN
SS
PGOOD
R7
100K
INTVCC
R25
0
R22
OPT
VOUT
VIN+
C8
C7
121K
R21
13K
RC
CC1
100
100
VOUT
0.01uF
CC2
R10
R9
INTVCC
CF
22pF
VOS+
C11
68pF
R14
100
50V
R13
100
C24
1uF
16V
17
9
8
7
6
5
4
3
2
1
EXTVCC
ILIM
VOUTSNS
VINSNS
RUN
FREQ
MODE/PLLIN
SGND
ITH
SENSE1-
SENSE1+
SS
VFB
C10
2.2uF
TG1
TRIM
SW2
TG2
BOOST2
BG2
INTVCC
BG1
PGND
BOOST1
SW1
4
1. ALL RESISTORS ARE 0603.
ALL CAPACITORS ARE 0603.
NOTE: UNLESS OTHERWISE SPECIFIED
R26
10
0805
0.1uF
0.1uF 50V
100pF
28
27
26
U1
LTC3789EUFD
25
PGOOD
4
IOSENSE+
10
19
VIN
IOSENSE-
11
SGND
29
0
100
INTVCC
R27
10
R5
3
VIN+
R18
0.015
1W
R1 0
R6 OPT
C22
0.22uF
16V
6.3V
D7
DFLS160
C18 10uF
4
Q1A
Si4288DY
C4
0.22uF
16V
Q1B
Si4288DY
2
R12 OPT
D4
DFLS160
0
R17 0
R23 0
R11
R4
R3 100
12
13
14
15
16
18
20
21
22
24
23
C15
1uF
50V
0805
3
7
8
1
5
6
3
D5
DFLS160
XAL7070
L1 5.6uH
C12
(OPT)
1206
R28
(OPT)
1206
R29
(OPT)
C13
(OPT)
D6
DFLS160
C17
C16
22uF
16V
1210
C14
(OPT)
1210
2
C29
C23
(OPT)
1210
2
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
0.25W
R2 0.015
R20 0
__
ECO
SCALE = NONE
C26
10uF
50V
1210
1
+
TP14
R8
10
VOS+
TP13
TP7
TP6
TP3
DATE
4-23-12
GND
12V / 2.5A MAX
VOUT
GND
VIN
6V - 36V
VIN+
CHARLIE Z.
APPROVED
DATE:
N/A
SIZE
1
LTC3789EUFD
DEMO CIRCUIT 1881A
Tuesday, May 15, 2012
IC NO.
SHEET 1
OF 1
2
REV.
HIGH EFFICIENCY COMPACT BUCK-BOOST CONVERTER
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900 www.linear.com
Fax: (408)434-0507
LTC Confidential-For Customer Use Only
COUT1
OPT
16V
VOUT
PRODUCTION
DESCRIPTION
REVISION HISTORY
TECHNOLOGY
C19
C20
22uF
16V
1210
2
REV
CHARLIE Z. TITLE: SCHEMATIC
HZ
APPROVALS
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.
CUSTOMER NOTICE
2
C35
(OPT)
1210
VOUT1
Q2B
Si4288DY
4
Q2A
Si4288DY
C9
C25
10uF
50V
1210
5
6
3
7
8
1
5
A
B
C
D
DEMO MANUAL DC1881A
SCHEMATIC DIAGRAM
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DEMO MANUAL DC1881A
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
dc1881af
6
Linear Technology Corporation
LT 0612 • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507 ● www.linear.com
© LINEAR TECHNOLOGY CORPORATION 2012
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