DC1940A - Demo Manual

DEMO MANUAL DC1940A
Low Quiescent Current,
High Voltage Step-Down
Converter
DESCRIPTION
Demonstration circuit 1940A is a low quiescent current,
synchronous buck converter featuring the LTC®3891EUDC.
This demo board converts a 16V to 60V voltage to a 12V
at 15A output.
The main features of this board include an internal LDO
for gate drive power from VIN or EXTVCC, RUN and
PGOOD pins, a mode selector that allows the converter
to run in constant current mode (CCM), pulse-skipping or
Burst Mode® operation, and selectable current limit. The
DC1940A supports an adjustable output voltage, soft-start
and tracking. The wide input voltage range of 16V to 60V is
suitable for double battery automotive and distributed DC
power systems where low quiescent current is important.
The LTC3891 data sheet gives a complete description of
this part, operation and application information. The data
sheet must be read in conjunction with this quick start
guide for demo circuit 1940A.
The 60V avalanche rated MOSFETs, which are used
on DC1940A, can be operated at their rated voltage.
However, if application derating requirements are
stricter, MOSFETs with higher voltage rating can be used.
PERFORMANCE SUMMARY
PARAMETER
Please note, MOSFETs with higher voltage ratings may affect the efficiency. If 60V MOSFETs are used, the MOSFET
avalanche rating and testing is typically done with 30%
over voltage margin (78V for 60V rated MOSFET). Please
check with particular MOSFET manufacturer to ensure the
avalanche voltage rating.
The DC1940A supports the following MOSFET packages:
LFPAK, PowerPAK SO-8 and Power 56. The subsequent
logic level (SV gate) MOSFETs can be used with DC1940A.
Si7850DP
Vishay
RJK0651DPB
Renesas
HAT2266H
Renesas
BSC100N06LS3 G
Infineon
FDMS86520L
Fairchild
For synchronization to an external clock, remove jumper
JP2 and apply sync signal on terminal SYNC.
Design files for this circuit board are available at
http://www.linear.com/demo
L, LT, LTC, LTM, Burst Mode, 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
VALUE
UNITS
Minimum Input Supply Voltage
16
V
Maximum Input Supply Voltage
60
V
12 ± 2%
V
Output Voltage Range
VIN = 16V to 60V, IOUT1 = 0A to 5A
Typical Switching Frequency
Typical Output Ripple (VOUT, 12V)
ILOAD = 15A
Efficiency Typical (VOUT, 12V)
125
kHz
80
mV
97
%
Supply Quiescent Current
VIN = 24V; VOUT = 12V, IO = 0A, Burst Mode Operation
50.8
μA
Supply Shutdown Current
VIN = 24V
14.7
μA
dc1940af
1
DEMO MANUAL DC1940A
QUICK START PROCEDURE
Demonstration circuit 1940A is easy to set up to evaluate
the performance of the LTC3891EUDC. Refer to Figure 1
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 2 for proper scope
probe technique.
3. Turn on the power at the input. Check for the proper
output voltages:
VOUT1 = 11.9V to 12.4V
NOTE: If there is no output, temporarily disconnect the
load to make sure that the load is not set too high.
4. Once the proper output voltages are established, adjust
the load within the operating range and observe the
output voltage regulation, ripple voltage, efficiency and
other parameters.
1. Place jumper JP1 in the ON position.
2. With power off, connect the input power supply to VIN
and GND.
DC1940a F01
Figure 1. Proper Measurement Equipment Setup
dc1940af
2
DEMO MANUAL DC1940A
QUICK START PROCEDURE
GND
VIN
DC1940a F02
Figure 2. Measuring Input or Output Ripple
99
98
16V
24V
48V
97
EFFICIENCY (%)
96
95
94
93
92
91
90
89
0.01
0.1
1
LOAD (A)
10
100
DC1940a F03
Figure 3. 12V Output, Efficiency vs Load, Burst Mode Operation, VIN 16V, 24V, 48V
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3
DEMO MANUAL DC1940A
PARTS LIST
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
Required Circuit Components
1
3
C1, C2, C10
CAP, X7R, 2.2μF 100V 10%, 1812
TDK, C4532X7R2A225K
2
1
C3
CAP, EL, 56μF/63V, F4
SUN EL, 63HVH56M
3
1
C4
CAP, X7R, 0.1μF 100V 10%, 0603
MURATA, GRM188R72A104KA35D
4
1
C5
CAP, NPO,10pF, 50V, 5%, 0603
AVX, 06031A100JAT2A
5
2
C9, C13
CAP, X7R, 0.1μF 50V 10%, 0603
TDK, C1608X7R1H104K
6
1
C6
CAP, X5R, 4.7μF, 16V, 10%, 0805
MURATA, GRM219R61C475KE15D
7
2
C7, C17
CAP, X7R, 1μF 16V, 10%, 0603
TDK, C1608X7R1C105K
8
1
C8
CAP, NPO, 2.2pF 50V, ±0.25pF, 0603
AVX, 06035A2R2CAT
9
1
C12
CAP, X7R, 4700pF, 10V, 5%, 0603
AVX, 0603ZC472JAT2A
10
1
C14
CAP, NPO, 47pF 50V, 5%, 0603
NIC, NMC0603NPO470J50TRPF
11
1
C15
CAP, X7R, 10μF 16V 10%, 1206
MURATA, GCM31CR71C106KA64L
12
1
C16
CAP, SANYO, 150μF, 16V, 20%
SANYO, 16TSVPC150
13
1
D1
DIODE, POWER DI-123
DIODES/ZETEX, DFLS1100-7
14
1
L1
IND, 10μH, 7443631000
WÜRTH, 7443631000
15
1
Q1
SILICON N CHANNEL POWER MOSFET LFPAK
RENESAS, RJK0651DPB
16
1
Q2
SILICON N CHANNEL POWER MOSFET LFPAK
RENESAS, RJK0653DPB
17
1
RS1
RES, 0.003Ω 1W 1% 2512
PANASONIC ERJM1WSF3M0U
18
1
R1
RES, 2.2 1% 1/10W, 0603
VISHAY, CRCW06032R20FNEA
19
3
R2, R8, R10
RES, 0Ω 1% 1/16W, 0603
VISHAY, CRCW06030000Z0EA
20
2
R4, R20
RES, 100k 1% 1/16W, 0603
VISHAY, CRCW0603100KFKEA
21
1
R5
RES, 511k 1% 1/16W, 0805
VISHAY, CRCW0805511KFKEA
22
1
R6
RES, 30.1k 1% 1/10W, 0603
VISHAY, CRCW060330K1FKEA
23
1
R7
RES, 35.7k 1% 1/16W, 0603
VISHAY, CRCW060335K7FKEA
24
1
R13
RES, 100 1% 1/10W, 0603
VISHAY, CRCW0603100RFKEA
25
1
R14
RES, 1M 1% 1/10W, 0805
VISHAY, CRCW08051M00FKEA
26
1
R15
RES, 2Ω 1% 1/16W, 0603
VISHAY, CRCW06032R00FNEA
27
1
R16
RES, 57.6k 1% 1/16W, 0603
VISHAY, CRCW060357K6FKEA
28
1
R17
RES, 15.4k 1% 1/10W, 0603
VISHAY, CRCW060315K4FKEA
29
1
R18
RES, 1k 1% 1/16W, 0603
VISHAY, CRCW06031K00FKEA
30
1
U1
IC, LTC3891EUDC, QFN20EUDC-3X4
LINEAR TECHNOLOGY, LTC3891EUDC
Additional Demo Board Circuit Components
1
R3, R9, R11, C11, R12,
C18, C19, R19, R21
RES, 0603
OPT
2
C20, C21, C22
CAP, 7343
OPT
3
Q3, Q4 (OPT)
MOSFET, LFPAK
OPT
Hardware
1
10
E1 TO E10
TESTPOINT, TURRET, 0.094"
MILL-MAX, 2501-2-00-80-00-00-07-0
2
4
J1, J2, J3, J4
CONN, BANANA JACK, KEYSTONE-575-4
KEYSTONE 575-4
3
1
JP1
JMP, 3PIN 1 ROW, 0.079"
SULLINS, NRPN031PAEN-RC
4
1
JP2
JMP, 3PIN 2 ROW, 0.079"
SULLINS, NRPN032PAEN-RC
5
4
MTGS AT 4 CORNERS
STANDOFF, NYLON 0.5 1/2"
KEYSTONE, 8833(SNAP-ON)
6
2
XJP1, XJP2
SHUNT, 0.079" CENTER
SAMTEC, 2SN-BK-G
dc1940af
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
VIN
E8
JP1
RUN
E5
E4
E3
E2
R20
100K
E10
E9
C12
1K
R18
5
3
6
4
JP2 MODE
1
2
FCM
BURST
PULSE SKIP
4.7nF
3. FOR SYNCHRONIZATION REMOVE JUMPER JP2 'MODE'
AND CONNECT SOURCE OF THE SYNC SIGNAL TO
TERMINALS E8 'SYNC' AND E9 'GND'
2. INSTALL SHUNTS AS SHOWN.
5
C14
47pF
R17
R19
2.2
2
8
4
19
15
9
17
C18
OPT
4
INTVCC
15.4K
OPT
R21
OPT
18
1
16
C7
1uF
R4
100k
INTVCC
3
C11
OPT
C9
0.1uF
R12
OPT
R11
OPT
63HVH56M
SUN ELECT.
C3
56uF/63V
R8
0
VOUT
+
R1
3
R14
1 Meg
0805
OPT
R9
C1
2.2uF
100V
1812
VIN
2
R16
57.6K
VIN
C2
2.2uF
100V
1812
1. ALL RESISTORS AND CAPACITORS ARE 0603
NOTES:
GND
GND
J2
1
INTVCC
SYNC
OFF
ON
TRACK
EXTVCC
PGOOD
GND
GND
16 - 60V
J1
E1
ILIM
PLLIN/MODE
PGND
SGND
SGND
ITH
RUN
TRACK/SS
EXTVCC
PGOOD
VIN
LTC3891EUDC
U1
C4
0.1uF
100V
2
R15
INTVCC
INTVCC
4
C13
0.1uF
50V
VIN
Q2
3
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
2
OPT
4
C19
OPT
2
SCALE = NONE
VICTOR K
LT
APPROVALS
4
Q1
1812
C10
2.2uF
100V
R7
35.7K
R5
511K
0805
R2
0
VOUT
C5
10pF
RJK0653DPB
DFLS1100
RJK0651DPB
4
D1
C8
2.2pF
4.7uF
0805
C6
CUSTOMER NOTICE
13
11
10
12
6
5
14
7
20
30.1K
R6
R3
OPT
INTVCC
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.
BG
SW
TG
BOOST
SENSE+
SENSE-
INTVCC
VFB
FREQ
3
5
1
2
3
VIN
SGND
21
5
1
2
3
4
5
1
2
3
VIN
5
OPT
1
C16
+ 150uF
16V
16SVPC150M
VOUT
E7
J4
C17
1uF
DATE:
N/A
LTC3891EUDC
1
SHEET 1
DEMO CIRCUIT 1940A
Monday, March 26, 2012
IC NO.
LOW QUIESCENT CURRENT HIGH VOLTAGE STEP-DOWN CONVERTER
SIZE
DATE
VOUT
VOUT
03-26-12
GND
GND
12V / 15A
J3
E6
VICTOR K.
APPROVED
OF 1
2
REV.
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900 www.linear.com
Fax: (408)434-0507
LTC Confidential-For Customer Use Only
C15
10uF
1206
PRODUCTION
DESCRIPTION
REVISION HISTORY
TECHNOLOGY
OPT
7343
+
2512
10uH
C22
C21
C20
RS1
0.003
L1
Q4
100
2
REV
TITLE: SCHEMATIC
Q3
0
R13
__
ECO
R10
1
2
3
5
A
B
C
D
DEMO MANUAL DC1940A
SCHEMATIC DIAGRAM
dc1940af
5
DEMO MANUAL DC1940A
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
dc1940af
6
Linear Technology Corporation
LT 0612 • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
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