DC1998A - Demo Manual

DEMO MANUAL DC1998A
LTC3892
60V, Low IQ Dual Output High
Voltage Step-Down Converter
Description
Demonstration circuit 1998A is a high input voltage, high
efficiency synchronous dual output buck converter featuring the LTC®3892. The DC1998A has a wide input voltage
range of 6V to 60V. The output voltages are set to 5V and
12V, however, the output voltage can be set almost as high
as the input voltage (≤99% • VIN), with certain modifications. This demo board is capable of delivering up to 8A
from the 5V output and up to 5A from the 12V output.
The DC1998A supports three operation modes: forced
continuous mode, pulse-skipping and Burst Mode® operation. Forced continuous mode, reduces output voltage
ripple and yields a low noise switching spectrum. Burst
Mode operation employs a variable frequency switching
algorithm that minimizes the no-load input quiescent current and improves efficiency at light loads.
The DC1998A consumes less than 4µA of quiescent current
during shutdown and below 0.15 mA no-load quiescent
current when in Burst Mode operation with an input
voltage above 14V. However, if Ch2 is in shutdown and
Ch1 in sleep mode, the quiescent current can be as low
as 29µA. The DC1998A has a fixed operating frequency
Performance Summary
PARAMETER
of 200kHz and can be adjusted to frequencies between
50kHz and 900kHz.
The DC1998A is designed to support multiple footprints
of input/output capacitors and inductors to accommodate
a variety of applications.
The LTC3892 features an adjustable gate drive voltage.
The DC1998A is preset to provide a 10V gate drive voltage
(DRVCC) for the switching MOSFETs and has 7.5V/6.7V
rising/falling undervoltage lockout (UVLO) thresholds.
In addition, the LTC3892 features a continuously adjustable gate drive voltage (5V to 10V) and selectable UVLO
thresholds that allow the use and optimization of both
logic-level and standard threshold MOSFETs. See the
LTC3892 data sheet for a more complete description of
its functionality and applications. The LTC3892 data sheet
must be read in conjunction with this demo board manual
for demonstration circuit 1998A.
Design files for this circuit board are available at
http://www.linear.com/demo/DC1998A
L, LT, LTC, LTM, Linear Technology, Burst Mode 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
CONDITIONS
Minimum Input Voltage
VALUE
6V
Maximum Input Voltage
60V
Output Voltage VOUT1 Regulation
VIN = 8V – 55V
5V ± 2%
Output Voltage VOUT2 Regulation
VIN = 16V – 55V
12V ± 2%
Maximum Continuous Output Current
VOUT1
8A
Maximum Continuous Output Current
VOUT2
5A
Preset Operating Frequency
R14 = 35.7k
200kHz
External Clock Sync Frequency Range
75kHz to 850kHz
Efficiency
VIN = 16V, VOUT2 = 12V, IOUT = 3A
See Figure 3 Efficiency Curves for Complete Operating Range
97%
Typical Output Ripple VOUT
VIN = 36V, VOUT2 = 12V, IOUT = 3A (20MHz BW)
<35mVP-P
Quiescent Current at Shut-Down
VIN = 16V – 55V
<5µA
Input Current at No-Load
VIN = 16V – 55V
<1mA
dc1998afb
1
DEMO MANUAL DC1998A
Quick Start Procedure
Demonstration circuit 1998A is easy to set up to evaluate
the performance of the LTC3892. For proper measurement
equipment configuration, set up the circuit according to
the diagram in Figure 1. Before proceeding to test, insert
shunts into JP2, JP3 (RUN1, 2) into OFF position, which
connects the RUN pins to ground (GND), and thus shuts
down the outputs. Set jumper JP1 (MODE) into FC (forced
continuous mode) position.
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.
1.With the DC1998A set up according to the proper
measurement and equipment in Figure 1, apply 20V at
VIN. Measure VOUT; it should read 0V. If desired, one
can measure the shutdown supply current at this point.
The supply current will be approximately 5µA, or less,
in shutdown.
voltage should be regulating. Measure VOUT1, it should
measure 5V ±2% (do not apply more than the rated
maximum voltage of 60V to the board or the part
may be damaged). Vary the VOUT1 load, which should
not exceed 8A. Vary the input voltage from 6V to 55V.
VOUT1 should measure 5V ±2%.
3.Turn on VOUT2 of the circuit by inserting the shunt in
header JP3 (RUN2) into the ON position. The output
voltage should be regulating. Measure VOUT2, it should
measure 12V ±2% (do not apply more than the rated
maximum voltage of 60V to the board or the part may
be damaged). Vary the VOUT2 load, which should not
exceed 5A. Vary the input voltage from 16V to 55V.
VOUT2 should measure 12V ±2%.
4.Set output current to zero and move jumper JP1 (MODE)
into BURST MODE position and measure VOUT1 and
VOUT2.
5.Set output current to zero and move jumper JP1 (MODE)
into PLS SKIP position and measure VOUT1 and VOUT2.
2.Turn on VOUT1 of the circuit by inserting the shunt in
header JP2 (RUN1) into the ON position. The output
dc1998afb
2
DEMO MANUAL DC1998A
Quick Start Procedure
Figure 1. Proper Measurement Equipment Setup
GND
VIN
Figure 2. Measuring Input or Output Ripple
dc1998afb
3
DEMO MANUAL DC1998A
Quick Start Procedure
98
96
94
96
94
PERCENT (%)
PERCENT (%)
92
90
88
90
86
16V
24V
36V
48V
84
82
0.5
92
1.5
2.5
4.5
3.5
CURRENT (A)
5.5
6.5
16V
24V
36V
48V
88
7.5
86
0.5
1
1.5
2
2.5
3
3.5
CURRENT (A)
4.5
5
DC1998A F04
DC1998A F03
Figure 3. Efficiency vs Input Voltage, VOUT1,
Burst Mode Operation
4
Figure 4. Efficiency vs Input Voltage, VOUT2,
Burst Mode Operation
DC1998A F05
Figure 5. Thermal Map, VIN 60V, IOUT1 5V at 8A, IOUT2 12V
at 5A No Air Flow
dc1998afb
4
DEMO MANUAL DC1998A
Parts List
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
CAP, ALUM, 47µF, 63V, 20%, 10 X 10.5
SUN ELECT, 63HVH47M
Required Circuit Components
1
1
CIN1
2
7
C2, C3, C4, C19, C20, C36, C37
CAP, 2.2µF, X7R, 100V, 10%, 1210
AVX, 12101C225KAT2A
3
1
C5
CAP, 0.1µF, X7R, 100V, 10%, 0805
AVX, 08051C104KAT2A
4
1
C6
CAP, 4.7µF, X5R, 50V, 10%, 0805
MURATA, GRM21BR61E475KA12L
5
3
C8, C21, C22
CAP, 0.1µF, X7R, 100V, 10%, 0603
MURATA, GRM188R72A104KA35D
6
1
C9
CAP, 1µF, X5R, 35V, 10%, 0603
TAIYO YUDEN, GMK107BJ105KA-T
7
1
C10
CAP, 27pF, NP0, 25V, 5%, 0603
AVX, 06033A270JAT2A
8
2
C11, C12
CAP, 1800pF, C0G, 50V, 5%, 0603
MURATA, GRM1885C1H182JA01D
9
2
C17, C18
CAP, 1000pF, NP0, 50V, 10%, 0603
AVX, 06035A102KAT2A
10
2
C13, C14
CAP, 100pF, NP0, 100V, 10%, 0603
AVX, 06031A101KAT2A
11
2
C15, C16
CAP, 0.01µF, X7R, 100V, 10%, 0603
AVX, 06031C103KAT2A
12
2
C24, C27
CAP, 10µF, X5R, 35V, 10%, 1206
TAIYO YUDEN, GMK316BJ106KL-T
13
1
C31
CAP, POSCAP, 150µF, 16V, 7343
PANASONIC, 16TQC150MYF
14
1
C32
CAP, POSCAP, 470µF, 6.3V 7343
PANASONIC, 6TPE470MI
15
1
L1
IND, PWR, 5.6µH, 20%, XAL1010 SERIES
COILCRAFT, XAL1010-562MED
16
1
L2
IND, PWR, 15µH, 20%, XAL1010 SERIES
COILCRAFT, XAL1010-153MED
17
2
Q1, Q2
XSTR, MOSFET, N-CH, 80V, 100A, TDSON-8
INFINEON, BSC057N08NS3 G
18
2
Q3, Q5
XSTR, MOSFET, N-CH, 75V, 100A, TDSON-8
INFINEON, BSC036NE7NS3 G
19
1
RS1
RES, SENSE, 0.005Ω 1% 1/4W,1206
VISHAY, WSL12065L000FEA
20
1
RS2
RES, SENSE, 0.008Ω 1% 1/4W,1206
VISHAY, WSL12068L000FEA
21
2
R8, R24
RES, 100k, 1%, 1/10W, 0603
VISHAY, CRCW0603100KFKEA
22
2
R9, R15
RES, 1M, 1%, 1/10W, 0603
VISHAY, CRCW06031M00FKEA
23
1
R14
RES, 35.7k, 1%, 1/10W, 0603
VISHAY, CRCW060335K7FKEA
24
1
R21
RES, 20k, 1/10W, 1%, 0603
VISHAY, CRCW060320K0FKEA
25
1
R22
RES, 10k, 1/10W, 1%, 0603
VISHAY, CRCW060310K0FKEA
26
1
R25
RES, 7.15k, 1/10W, 1%, 0603
VISHAY, CRCW06037K15FKEA
27
1
U1
IC, LTC3892EUH#PBF, QFN32UH-5X5
LINEAR TECHNOLOGY, LTC3892EUH#PBF
dc1998afb
5
DEMO MANUAL DC1998A
Parts List
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
Additional Demo Board Circuit Components
1
0
CIN2
CAP, OPTION, 10 X 10.5
OPT
2
0
C1, C7, C29, C30
CAP, OPTION, 0603
OPT
3
0
C23, C28, C34, C35
CAP, OPTION, 1206
OPT
4
0
C25
CAP, OPT, OSCON-SVP-F8
OPT
5
0
C26
CAP, OPT, OSCON-SVP-C6
OPT
6
0
C33
CAP, OPTION, 0805
OPT
7
0
D1, D2
DIODE, OPT, DI-123
OPT
8
0
L3
IND, OPT
OPT
9
0
Q4, Q6
XSTR, OPT, WPACKV
OPT
10
1
R1
RES, 0Ω, JUMPER 1/18W, 0805
VISHAY, CRCW08050000Z0EA
11
16
R2, R3, R5, R6, R16, R18, R19,
R23, R29, R30, R32, R33, R34,
R35, R40, R41
RES, 0Ω, JUMPER 1/18W, 0603
VISHAY, CRCW06030000Z0EA
12
0
R4, R7, R10, R11, R12, R13,
R17, R20, R26, R27, R28, R31,
R38, R39
RES, OPTION, 0603
OPT
13
0
R36, R37
RES, OPTION, 0805
OPT
14
0
TP1, TP2
TEST PAD SMD
OPT
Hardware/Components (For Demo Board Only)
1
12
E1 TO E12
TESTPOINT, TURRET, 0.094" MTG. HOLE
MILL-MAX, 2501-2-00-80-00-00-07-0
2
1
JP1
CONN, HEADER, 2 x 3, 2mm
SULLINS, NRPN032PAEN-RC
3
2
JP2, JP3
CONN, HEADER, 1 x 3, 2mm
SULLINS, NRPN031PAEN-RC
4
3
XJP1, XJP2, XJP3
SHUNT, 2mm
SAMTEC, 2SN-BK-G
5
4
MTGS AT 4 CORNERS
STANDOFF, NYLON, SNAP-ON, 0.500" TALL
KEYSTONE, 8833
dc1998afb
6
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
E7
E9
7343
TP2
E12
E11
C10
C34
OPT
C35
OPT
C25
OPT
OPT
L3
C16
.01uF
R24
100k
27pF
5
1. ALL RESISTORS AND CAPACITORS ARE 0603.
C36
2.2uF
100V
1210
R21
INTVCC
15uH
L2
OPT
OFF
ON
Q1
JP2
3
2
1
RUN1
4
R40
0
VIN
4
OPT
R38
R36
OPT
0805
RUN1
VIN
Q4
OPT
4
4
0
R32
0
C6
DRVCC
C5
0.1uF
100V
0805
C29
OPT
C21
JP3
1
3
2
1
RUN2
0.1uF
OFF
ON
C17
1nF
19
17
16
10
9
6
15
12
11
21
4
3
20
22
2
R41
0
VIN
D1
OPT
0
R34 18
RUN1
EXTVCC
4.7uF 0805
R29
C19 VIN
2.2uF
1210 100V
C13
100pF
1 Meg
R15
1 Meg
R9
BSC057N08NS3 G
20K
C12
1800pF
R1
0
0805
+ CIN1
+ CIN2
47uF/63V
OPT
63HVH47M 63HVH47M
INTVCC
C37
2.2uF
100V
1210
C24
10uF
35V
Q3
1206
BSC036NE7NS3 G
0.008
1206
RS2
C33
VIN
C23
OPT
1206
R25
7.15k
R17
OPT
VOUT1
C4
2.2uF
100V
1210
C9
1uF
NOTE: UNLESS OTHERWISE SPECIFIED
GND
GND
GND
+
+
OPT
R28
OPT
VOUT2
Vin_EMI
TP1
GND
0
R23
C3
2.2uF
100V
1210
R16
0
VOUT2
C2
2.2uF
100V
1210
R26
E6
E5
E4
E3
E1
C31
150uF
16V
12V / 5A
VOUT2
VOUT1
VOUT2
EXTVCC
PGOOD2
PGOOD1
GND
6V UP TO 60V
VIN
4
5
VIN
5
3
2
1
3
OPT
R39
RUN2
R37
OPT
0805
VIN
DRVCC
BOOST2
BG2
SW2
TG2
SENSE2+
SENSE2-
RUN1
TRACK/SS2
ITH2
VFB2
EXTVCC
PGOOD2
PGOOD1
DRVCC
VIN
FREQ
DRVUV
DRVSET
ILIM
VPRG1
C30
OPT
DRVCC
BOOST1
BG1
SW1
TG1
SENSE1+
SENSE1-
RUN2
TRACK/SS1
ITH1
VFB1
INTVCC
PLLIN/MODE
U1
LTC3892EUH
3
GND
33
1
4
4
Q5
BSC036NE7NS3 G
0.1uF
C22
0
2
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
SCALE = NONE
VICTOR K.
LT
L1
1
3
5
C27
10uF
35V
1206
0.005
1206
RS1
BURST
2
4
6
C26
OPT
+
+
E10
DATE:
N/A
SIZE
LTC3892EUH
1
DEMO CIRCUIT 1998A
Monday, May 18, 2015
IC NO.
SHEET 1
2
OF 1
REV.
LOW IQ DUAL OUTPUT HIGH VOLTAGE STEP-DOWN CONVERTER
LTC Confidential-For Customer Use Only
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900 www.linear.com
GND
5V / 8A
C32
470uF 6.3V
7343
VOUT1
VOUT2
E8
DATE
5-18-15
SYNC
VOUT1
VOUT1
OPT
R27
C15
R31
.01uF OPT
10K
C11
1800pF
0
0
R22
R19
R18
TECHNOLOGY Fax: (408)434-0507
C28
OPT
1206
C14
100pF
INTVCC
C7
OPT
100K
R8
INTVCC
R20
OPT
JP1
MODE
0
E2
VICTOR K.
R2
APPROVED
PRODUCTION
2
1
DESCRIPTION
REVISION HISTORY
REV
TITLE: SCHEMATIC
Q6
OPT
APPROVALS
4
FC
C1
OPT
__
ECO
PLS SKIP
5.6uH
R14
35.7K
R7
OPT
INTVCC
BSC057N08NS3 G
Q2
C20
2.2uF
100V 1210
R13
OPT
R12
OPT
VIN
0
R33
R30
0.1uF
CUSTOMER NOTICE
D2
OPT
0
R35
R11
OPT
C8
C18
1nF
INTVCC
RUN2
ILIM
R10
OPT
R4
OPT
R6
0
R5
0
2
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
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
APP ENG.
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
2
24
23
25
26
31
32
7
27
29
30
5
2
1
13
14
8
28
R3
0
5
1
2
3
5
1
2
3
3
2
1
5
3
2
1
5
1
2
3
5
A
B
C
D
DEMO MANUAL DC1998A
Schematic Diagram
dc1998afb
7
DEMO MANUAL DC1998A
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
dc1998afb
8
Linear Technology Corporation
LT 0516 REV B • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507 ● www.linear.com
 LINEAR TECHNOLOGY CORPORATION 2015
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