DC1728A - Demo Manual

DEMONSTRATION CIRCUIT
1728A QUICK START GUIDE
LT3015
1.5A, Low Noise, Negative Linear Regulator
with Precision Current Limit
DESCRIPTION
Demonstration circuit 1728A is an adjustable 1.5A negative
linear regulator featuring the LT3015. This device supplies
up to 1.5A of output current at a typical dropout voltage
of 300mV. Operating quiescent current is typically 1.1mA
and drops to < 1μA in shutdown. Quiescent current is also
well controlled in dropout. In addition to fast transient
response, the LT3015 exhibits very low output noise,
making it ideal for noise-sensitive applications.
A key feature of the LT3015 is the capability to supply a
wide output voltage range. The DC1728A can be set to
–1.22V, –2.5V, –5.0V, –12.0V, –15.0V, as well as a user
select option. In addition, the DC1728A is capable of delivering up to –1.5A output current, and can be used as a
high current negative linear regulator, post regulator for
switching supply, variable voltage supply or low output
voltage power supply.
PERFORMANCE SUMMARY
Internal protection circuitry includes reverse output protection, precision current limit with foldback and thermal
limit with hysteresis.
The LT3015 is available as an adjustable device with a
–1.22V reference voltage. Packages include the 5-lead
TO-220 and DD-Pak, a thermally enhanced 12-lead MSOP
and the low profile 8-lead 0.75mm × 3mm × 3mm DFN.
The LT3015 datasheet gives a complete description of the
device, operation and application information. The datasheet should be read in conjunction with this quick start
guide for working on or modifying the demo circuit 1728A.
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.
(TA = 25°C)
SYMBOL
PARAMETER
CONDITIONS
MIN
VIN
Input Supply Range
VOUT = –1.22V, IOUT1 = –1mA
–1.8
TYP
MAX
UNITS
–30
V
VOUT
Output Voltage
Shunt at 1, 2 for JP2
–1.183
–1.22
–1.257
V
VOUT
Output Voltage
Shunt at 3, 4 for JP2
–2.425
–2.5
–2.575
V
VOUT
Output Voltage
Shunt at 5, 6 for JP2
–4.85
–5.0
–5.15
V
VOUT
Output Voltage
Shunt at 7, 8 for JP2
–11.64
–12.0
–12.36
V
VOUT
Output Voltage
Shunt at 9, 10 for JP2
–14.55
–15.0
–15.45
V
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DEMONSTRATION CIRCUIT
1728A QUICK START GUIDE
QUICK START PROCEDURE
Demonstration circuit 1728A is easy to set up to evaluate the performance of the LT3015. 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 terminals of the input or output capacitors. See
Figure 2 for proper scope probe technique.
1. Place JP1 on the ON position.
NOTE. Put JP1 = 1-2 for ON, JP1 = 1-4 for OFF, or
JP1 = 1-3 for User Select.
2. Use JP2 to set the desired output voltage.
3. With power off, connect the input power supply to VIN
and GND.
4. Turn on the power at the VIN.
NOTE. Make sure that the VIN voltage does not exceed
–30V.
5. 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.
6. 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.
Figure 1. DC1728A Proper Equipment Setup
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DEMONSTRATION CIRCUIT
1728A QUICK START GUIDE
QUICK START PROCEDURE
Thermal Image
GND
VIN
An example thermal image (Figure 3) shows the temperature
distribution on the board. The test is done in still air at room
temperature with 1.96W power dissipation in the LT3015.
This gives the IC case-to-ambient thermal resistance
θJA = 23°C/W on the demo board.
Figure 2. Measuring Input or Output Ripple
Figure 3. Temperature Rise at 1.96W Dissipation
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DEMONSTRATION CIRCUIT
1728A QUICK START GUIDE
PARTS LIST
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
Required Circuit Components
1
1
CIN
CAP., X7R, 10μF 50V, 10%, 1210
MURATA, GRM32ER71H106K
2
1
COUT
CAP., X7R, 10μF 25V, 10%, 1206
MURATA, GRM31CR71E106KA12L
3
1
R1
RES., CHIP, 3.48k, 1/16W, 1% 0402
VISHAY, CRCW04023K48FKED
4
2
R2, RSD
RES., CHIP, 0Ω, 0402
VISHAY, CRCW04020000Z0ED
5
1
R3
RES., CHIP, 3.65k, 1/16W, 1% 0402
VISHAY, CRCW04023K65FKED
6
1
R4
RES., CHIP, 11.0k, 1/16W, 1% 0402
VISHAY, CRCW040211K0FKED
7
1
R5
RES., CHIP, 30.9k, 1/16W, 1% 0402
VISHAY, CRCW040230K9FKED
8
1
R6
RES., CHIP, 39.2k, 1/16W, 1% 0402
VISHAY, CRCW040239K2FKED
9
1
R9
RES., CHIP, 100k, 1/16W, 1% 0402
VISHAY, CRCW0402100KFKED
U1
I.C., LT3015EDD, DFN8DD
LINEAR TECH., LT3015EDD
Additional Demo Board Circuit Components
1
1
C1
CAP., ALUM., 10μF 50V, CE-BSS
2
0
C2
CAP., 7343
3
0
R7, R8
RES., CHIP, 0402
SUNCON, 50CE10BSS
Hardware-For Demo Board Only
1
5
E1-E5
TP, TURRET, 0.094"
MILL-MAX, 2501-2-00-80-00-00-07-0
2
1
JP1
JMP, 4 PINS, 0.079"
SAMTEC, ASP-157349-01
3
1
JP2
JMP, 2 × 6, 0.079"
SAMTEC, TMM-106-02-L-D
4
2
XJP1, XJP2
SHUNT, .079" CENTER
SAMTEC, 2SN-BK-G
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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
CIN
10uF
50V
1210
3
USER
SELECT
JP1
R8
OPT
2
1 ON
4 OFF
RSD
0
R9
100k
5
2. INSTALL SHUNTS AS SHOWN.
1. ALL RESISTORS ARE IN OHMS, 0402.
ALL CAPACITORS ARE IN MICROFARADS.
3
2
1
SHDN
IN
IN
ADJ
OUT
OUT
6
7
8
4
3
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
R2
0
SCALE = NONE
EDWIN L.
KT
APPROVALS
R1
3.48k
U1
LT3015EDD
3
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
CAPACITOR C1 IS AN OPTIONAL PART. IT WAS INSERTED ON THE DC1728A TO
DAMPEN THE (POSSIBLE) RINGING VOLTAGE DUE TO THE USE OF LONG INPUT
LEADS. ON A NORMAL, TYPICAL PCB, WITH SHORT TRACES, THE CAPACITOR
IS NOT NEEDED. SEE APPLICATION NOTE AN88 FOR MORE DETAILS.
E4
SUNCON
50CE10BSS
10uF
50V
*C1
NOTES: UNLESS OTHERWISE SPECIFIED
*
SHDN
E2
VIN
VIN
-1.9V TO -30V
E5
GND
+
D
9
IN
GND
4
GND
5
1
REV
R4
11.0k
DATE:
N/A
SIZE
R6
39.2k
C2
OPT
7343
E3
E1
GND
VOUT
-1.5A MAX
EDWIN L.
VOUT
DATE
04-20-11
APPROVED
1
IC NO.
2
Wednesday, April 20, 2011
LT3015EDD
DEMO CIRCUIT 1728A
1
SHEET 1
1.5A, LOW NOISE, NEGATIVE REGULATOR
WITH PRECISION CURRENT LIMIT
OF 1
1
REV.
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900 www.linear.com
Fax: (408)434-0507
LTC Confidential-For Customer Use Only
R7
OPT
COUT
10uF
25V
1206
PRODUCTION
DESCRIPTION
REVISION HISTORY
TECHNOLOGY
R5
30.9k
JP2
HD2X6-079
TITLE: SCHEMATIC
R3
3.65k
_
ECO
2
-1.22V
-2.5V
-5.0V
-12.0V
-15.0V
USER
SELECT
2
4
6
8
10
12
1
3
5
7
9
11
4
+
5
A
B
C
D
DEMONSTRATION CIRCUIT
1728A QUICK START GUIDE
SCHEMATIC DIAGRAM
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DEMONSTRATION CIRCUIT
1728A QUICK START GUIDE
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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Linear Technology Corporation
LT 0611 • 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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