Linear Technology DC2548A Quick setup guide

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dc2548af
DEMO MANUAL DC2548A
Description
LT8672
Active Rectifier Controller
with Reverse Protection
Demonstration circuit 2548A is an active rectifier with
reverse protection featuring the LT
®
8672. The demo
board is designed for 5A load current. The input volt-
age range of the LT8672 is –40V to +42V. Two clamping
diodes, D1 and D2, are used on the board to protect the
IC from overvoltage spikes at the input, thus limiting the
application’s DC input voltage range to –15V and +35V.
The voltage drop on the MOSFET is 20mV in regulation.
The LT8672 can rectify input ripple with an amplitude of
6VP-P and a frequency of up to 50kHz, or with an ampli-
tude of 2VP-P and a frequency of up to 100kHz. High fre-
quency ripple should not be applied at full load current
for more than a few minutes, otherwise C5 may overheat.
JP1 can be used to set the LT8672 in shutdown mode.
It can be turned on by connecting the EN/UVLO to VIN or
VOUT. A digital signal can also be applied at the EN/UVLO
turret to control the part. Due to the presence of the exter-
nal MOSFET’s body diode, the load is not disconnected
from the input if the part is shut down. L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Analog
Devices, Inc. All other trademarks are the property of their respective owners.
performance summary
The PG pin on the demo board can be easily by applying
a voltage source between VEXT and GND. VEXT must not
exceed 5V.
The demo board allows installation of an EMI filter at the
output. To use the EMI filter, install L2, C7, and remove
C5 on the board. In addition, multiple MOSFET footprints
are provided on the backside of the board, making it con-
venient to use other MOSFETs.
The LT8672 data sheet gives a complete description of
the part, operation and application information. The data
sheet must be read in conjunction with this demo manual
for demo circuit 2548A. The LT8672 is assembled in a
10-lead MSOP package. Proper board layout is essential
for maximum thermal and electrical performance. See the
data sheet sections for details.
Design files for this circuit board are available at
http://www.linear.com/demo/DC2548A
Specifications are at TA= 25°C
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VIN DC Operating Input Voltage Range –15 35 V
f (AC) Maximum Frequency of AC Input Signal to
BeRectified
VP-P < 6V, CGATE-SOURCE = 10nF 50 kHz
VP-P < 2V, CGATE-SOURCE = 10nF 100 kHz
IOUT Max Output Current VIN=12V 5 A
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DEMO MANUAL DC2548A
performance summary
Figure 1. Rectification of Input Ripple (f = 30kHz, Load = 5A)
10µs/DIV
VBATT
1V/DIV
VOUT
1V/DIV
DC2548 F01
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DEMO MANUAL DC2548A
Quick start proceDure
Demonstration circuit 2548A is easy to set up to evalu-
ate the performance of the LT8672. Refer to Figure 2 for
proper measurement equipment setup and follow the
procedure below:
1. Place JP1 on VOUT or VIN position.
2. Connect the input power supply to VIN and GND.
3. Connect a load from VOUT to GND.
4. Turn on the power at the input.
5. Checkfortheproperoutputvoltages(VOUT= VIN– 2 0 mV).
The demo board provides test points TP1 and TP3 to
accurately measure the voltage across the external
MOSFET.
NOTE. If there is no output, temporarily disconnect the
load to make sure that the load is not shorted.
6. Once the proper output voltage is established, adjust
the load within the operating ranges and observe the
output voltage.
7. To use the PG pin, connect a power source at VEXT
that is not higher than 5V.
8. Test point TP5 allows easy access to the voltage at
the AUX pin. The gate-source voltage can be observed
between TP2 and TP4.
Figure 2. Proper Measurement Equipment Setup
DC2548 F02
+
–
+–
VOUT
IOUT
IIN
LOAD
+
–
+
–
+
–
VIN
+–
POWER
SUPPLY
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DEMO MANUAL DC2548A
parts List
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
Required Circuit Components
1 1 C1 CAP., CER., 0.01µF, X7R, 50V, 10%, 0805 MURATA, GRM216R71H103KA01D
2 2 C2, C3 CAP., CER., 1µF, X7R, 50V, 10%, 0805 MURATA, GRM21BR71H105KA12L
3 1 C4 CAP., CER., 4.7µF, X7R, 50V, 10%, 1210 MURATA, GRM32ER71H475KA88L
4 1 C5 CAP., ALUM., 470µF, 35V, 20% VISHAY, MAL214699006E3
8 1 D1 DIODE, TVS, 15VWM, SMB DIODES INC., SMBJ15A-13-F
9 1 D2 DIODE, TVS, 33VWM, SMB DIODES INC., SMBJ33A-13-F
16 1 L1 IND., 100µH, XPL2010 COILCRAFT, XPL2010-104MLB
18 1 Q1 XSTR., N-CH, 60V, MOSFET, TO252 INFINEON, IPD100N06S403ATMA2
19 1 R1 RES., 1M, 1%, 1/8W, 0805 VISHAY, CRCW08051M00FKEA
20 1 R2 RES., 100k, 1%, 1/8W, 0805 VISHAY, CRCW0805100KFKEA
23 1 U1 I.C., CONTROLLER, 10-MSOP LINEAR TECH., LT8672EMS#PBF
Additional Demo Board Circuit Components
5 0 C6 (OPT) CAP., OPTION, 0805
6 0 C7 (OPT) CAP., ALUM, OPTION, 12.5X16mm
7 0 C8 (OPT) CAP., OPTION, 1206
17 0 L2 (OPT) IND., OPTION, XAL1010
21 0 R3 (OPT) RES., OPTION, 0805
22 0 R4 (OPT) CAP., OPTION, 1206
Hardware: For Demo Board Only
10 7 E1–E7 TEST POINT, TURRET, 0.094" MTG. HOLE MILL-MAX, 2501-2-00-80-00-00-07-0
11 0 E8 (OPT) TEST POINT, OPTION, TURRET
12 1 JP1 HEADER 3 PIN 0.079 DOUBLE ROW WURTH ELEKTRONIK, 62000621121
13 1 XJP1 SHUNT, 0.079" CENTER WURTH ELEKTRONIK, 60800213421
14 4 J1-J4 CONN., BANANA JACK KEYSTONE, 575-4
15 0 J5 (OPT) CONN., OPTION, BANANA JACK
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DEMO MANUAL DC2548A
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
A
A
B
B
C
C
D
D
E
E
4 4 3 3 2 2 1 1
1. ALL RESISTORS ARE 0805. ALL CAPACITORS ARE 0805.
NOTE: UNLESS OTHERWISE SPECIFIED
OPTIONAL
VEMI
SEE DEMO MANUAL
*
**
VIN VOUT
VIN VOUT GND
C3 1uF 50V
U1
LT8672EMS
SOURCE
9
PGND
5
AUXSW
6
EN/UVLO
1
PG
3
DRAIN
8
GND
2
GATE
10
AUX
7
GND
4
TP1
J4 GND
TP4
JP1
EN/UVLO
1 2 3 4 5 6
+
C7 OPT
12
+
C5 470uF
35V MAL214699006E3
12
R2 100k
C8 OPT 1206
E6
PG
C1 10nF 50V
TP6
C2 1uF 50V
D2
SMBJ33A
2 1
C4 4.7uF 50V 1210
E3
VOUT
Q1
IPD100N06S4-03
2
1
3
J3
VOUT
C6 OPT
L2
OPT
XAL1010-222ME
12
E8 E4
GND
E5
EN/UVLO
TP2
J1
VIN TP3
J5
J2
GND
E1
VIN
TP8
L1 100uH XPL2010-104ML
12
D1
SMBJ15A
21
TP5
R4 OPT 1206
E7
VEXT
R1 1M
E2
GND
R3
OPT
TP7
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DEMO MANUAL DC2548A
 LINEAR TECHNOLOGY CORPORATION 2017
LT 0917 • 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:
Linear Technology
1630 McCarthy Blvd.
Milpitas, CA 95035
Copyright © 2004, Linear Technology Corporation
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