DC1585A - Demo Manual

DEMO MANUAL DC1585A
LT3083
Adjustable 3A Single Resistor
Low Dropout Regulator
DESCRIPTION
Demonstration circuit 1585A is an adjustable 3A linear
regulator featuring LT3083. Architected as a precision
current source and voltage follower, it allows this new
regulator to be used in many applications requiring high
current, adjustability to zero output, and no heat sink. Also
the device brings out the collector of the pass transistor
to allow low dropout operation when used with multiple
supplies.
A key feature of the LT3083 is the capability to supply a
wide output voltage range. DC1585A can be set to 1.2V,
1.5V, 1.8V, 2.5V, 3.3V, 5.0V, as well as user selectable.
DC1585A is capable of delivering up to 3A output current.
DC1585A can be used as a high current linear regulator,
a post regulator for switching supplies, a variable voltage
supply or low output voltage power supply.
PERFORMANCE SUMMARY
Internal protection circuitry includes current limiting and
thermal limiting.
LT3083 regulator is offered in a 16-lead TSSOP (with an
exposed pad for better thermal characteristics), a 4mm ×
4mm DFN, 5-lead TO-220 and a 5-lead DD-PAK version.
The LT3083 datasheet gives a complete description of the
part, operation and application information. The datasheet
should be read in conjunction with this quick start guide
for working on or modifying the demo circuit 1585A.
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.
Specifications are at TA = 25°C
SYMBOL
PARAMETER
CONDITIONS
MIN
VIN
Input Supply Range
VOUT = 1.2V, IOUT1 = 1mA
1.7
TYP
MAX
23
UNITS
V
VCONTROL
VCONTROL Voltage
VOUT = 1.2V, IOUT1 = 1mA
2.8
25
V
VOUT
Output Voltage
Shunt at 1, 2 for JP1
1.14
1.2
1.26
V
Shunt at 3, 4 for JP1
1.425
1.5
1.575
V
Shunt at 5, 6 for JP1
1.71
1.8
1.89
V
Shunt at 7, 8 for JP1
2.375
2.5
2.625
V
Shunt at 9, 10 for JP1
3.201
3.3
3.399
V
Shunt at 11, 12 for JP1
4.85
5.0
5.15
V
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DEMO MANUAL DC1585A
QUICK START PROCEDURE
Demonstration circuit 1585A is easy to set up to evaluate the performance of the LT3083. Refer to Figure 1 for
the 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 terminals of the input or output capacitors. See
Figure 2 for the proper scope probe technique.
1. Use JP1 to set the desired output voltage.
2. With power off, connect the bias power supply to
VCONTROL and GND.
5. Turn on the power at VIN.
NOTE. Make sure that the VIN voltage does not exceed
23V.
6. Check for the proper output voltages.
NOTE. If there is no output, temporarily disconnect
the load to make sure that the load is not set too high
or is shorted.
7. Once the proper output voltages are established, adjust
the loads within the operating range and observe the
output voltage regulation, efficiency and other parameters.
NOTE. Make sure that the power dissipation is limited
below the thermal limit.
3. With power off, connect the input power supply to VIN
and GND.
4. Turn on the power at VCONTROL.
NOTE. Make sure that the VCONTROL voltage does not
exceed 25V.
+
+
–
LOAD
–
+
–
–
POWER
SUPPLY
+ +
–
–
–
+
–
–
+
+
POWER
SUPPLY
+
Figure 1. DC1585A Proper Equipment Setup
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2
DEMO MANUAL DC1585A
QUICK START PROCEDURE
GND
VIN
Figure 2. Measuring Input or Output Ripple
THERMAL IMAGE
An example thermal image shows the temperature distribution on the board. The test is done in still air at room
temperature with 6.4W power dissipation in the LT3083.
This gives the IC case-to-ambient thermal resistance
θJA=7.3°C/W on the demo board.
Figure 3. Temperature Rise at 6.4W Dissipation
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DEMO MANUAL DC1585A
PARTS LIST
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
Required Circuit Components
1
2
C1, C2
CAP., X5R 4.7μF 50V 10% 1206
TAIYO YUDEN UMK316BJ475KLT
2
1
C3
CAP., X5R 22μF 16V 10% 1206
AVX 1206YD226KAT2A
3
1
C4
CAP., X7R 0.01μF 16V 10% 0603
AVX 0603YC103KAT2A
4
1
R1
RES., CHIP 24.3k 1/10W 1% 0603
VISHAY CRCW060324K3FKEA
5
1
R2
RES., CHIP 35.7k 1/10W 1% 0603
VISHAY CRCW060335K7FKEA
6
1
R3
RES., CHIP 49.9k 1/10W 1% 0603
VISHAY CRCW060349K9FKEA
7
1
R4
RES., CHIP 66.5k 1/10W 1% 0603
VISHAY CRCW060366K5FKEA
8
1
R5
RES., CHIP 100k 1/10W 1% 0603
VISHAY CRCW0603100KFKEA
9
1
R7
RES., CHIP 499 1/10W 1% 0805
VISHAY CRCW0805499RFKEA
10
1
R8
RES., CHIP 30.1k 1/10W 1% 0603
VISHAY CRCW06030K1FKEA
11
1
U1
I.C., LT3083EQ Q PACKAGE
LINEAR TECH. CORP. LT3083EQ#PBF
Additional Demo Board Circuit Components
1
1
CIN
CAP., ALUMINUM. 10μF 50V 10%
2
0
R6(OPT)
RES., 0603
SANYO 63CE22BS
Hardware-For Demo Board Only:
1
5
E1-E5
TESTPOINT, TURRET, .095"
MILL MAX 2501-2-00-80-00-00-07-0
2
1
JP1
2mm DOUBLE ROW HEADER, 2 × 7 PIN
SAMTEC TMM-107-02-L-D
3
1
XJP1
SHUNT
SAMTEC 2SN-BK-G
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4
B
A
VIN
E3
E2
E1
+
CIN *
10uF
50V
*
C2
4.7uF
50V
1206
C1
4.7uF
50V
1206
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.
1
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A
CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;
HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO
VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
C4
0.01uF
EDWIN L.
APP ENG.
SCALE = NONE
HZ
PCB DES.
APPROVALS
13
11
10 3.3V
12 5.0V
9
R5
R1
R7
499
0805
E5
E4
DATE
02-02-10
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900 www.linear.com
Fax: (408)434-0507
LTC Confidential-For Customer Use Only
EDWIN L.
APPROVED
DATE:
N/A
SIZE
LT3083EQ
DEMO CIRCUIT 1585A
2
Tuesday, November 09, 2010
IC NO.
SHEET 1
OF 1
2
REV.
ADJUSTABLE 3A SINGLE RESISTOR LDO REGULATOR
TITLE: SCHEMATIC
(OPT)
66.5K 1%
R6
GND
VOUT
ADJ., 3A MAX
2nd PROTOTYPE
DESCRIPTION
REVISION HISTORY
TECHNOLOGY
14 USER 100K 1%
SELECT
2.5V
8
1.8V
6
7
4
3
R8
C3
22uF
16V
10%
1206
2
REV
2
24.3K 1%
R2
30.1K 1%
R3 35.7K 1%
R4
49.9K 1%
__
ECO
1.2V
1.5V
5
2
JP1
NC 1
OUT 6
OUT 3
1
LT3083EQ
4 VCONTROL
5 IN
CUSTOMER NOTICE
CIN IS OPTIONAL, FOR VIN PAMPING PURPOSE ONLY.
2. INSTALL SHUNTS AS SHOWN.
1. ALL RESISTORS AND CAPACITORS ARE IN 0603.
NOTE: UNLESS OTHERWISE SPECIFIED
GND
VCONTROL
2.8V - 25V
1.7V - 23V
U1
SET
2
1
B
A
DEMO MANUAL DC1585A
SCHEMATIC DIAGRAM
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5
DEMO MANUAL DC1585A
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
dc1585af
6
Linear Technology Corporation
LT 0211 • 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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