Linear Technology LT3015 Quick start guide
- Category
- Voltage regulators
- Type
- Quick start guide
1
dc1728af
DEMONSTRATION CIRCUIT
1728A QUICK START GUIDE
DESCRIPTION
LT3015
1.5A, Low Noise, Negative Linear Regulator
with Precision Current Limit
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 < 1A 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 de-
livering 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.
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.
PERFORMANCE SUMMARY
Internal protection circuitry includes reverse output pro-
tection, 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 data-
sheet 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
(TA = 25°C)
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VIN Input Supply Range VOUT = –1.22V, IOUT1 = –1mA –1.8 –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
2
dc1728af
DEMONSTRATION CIRCUIT
1728A QUICK START GUIDE
QUICK START PROCEDURE
Figure 1. DC1728A Proper Equipment Setup
Demonstration circuit 1728A is easy to set up to evalu-
ate 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.
3
dc1728af
DEMONSTRATION CIRCUIT
1728A QUICK START GUIDE
QUICK START PROCEDURE
Figure 2. Measuring Input or Output Ripple
Figure 3. Temperature Rise at 1.96W Dissipation
V
IN
GND
Thermal Image
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.
4
dc1728af
DEMONSTRATION CIRCUIT
1728A QUICK START GUIDE
PARTS LIST
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
Required Circuit Components
11C
IN CAP., X7R, 10µF 50V, 10%, 1210 MURATA, GRM32ER71H106K
21C
OUT 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, 0, 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 SUNCON, 50CE10BSS
2 0 C2 CAP., 7343
3 0 R7, R8 RES., CHIP, 0402
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
5
dc1728af
DEMONSTRATION CIRCUIT
1728A QUICK START GUIDE
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
5
5
4
4
3
3
2
2
1
1
D D
C C
BB
AA
ALL CAPACITORS ARE IN MICROFARADS.
NOTES: UNLESS OTHERWISE SPECIFIED
2. INSTALL SHUNTS AS SHOWN.
1. ALL RESISTORS ARE IN OHMS, 0402.
GND
SHDN
VOUT
-1.5A MAX
GND
*
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.
*
VIN
-1.9V TO -30V
-1.22V
-2.5V
-5.0V
-12.0V
-15.0V
USER
SELECT
SUNCON
50CE10BSS ON
OFF
USER
SELECT
VIN VOUT
SIZE
DATE:
.VER.ON CI
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: (408)434-0507
Milpitas, CA 95035
Phone: (408)432-1900
1630 McCarthy Blvd.
LTC Confidential-For Customer Use Only
CUSTOMER NOTICE
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.
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
SCALE = NONE
www.linear.com
1
LT3015EDD
111102 ,02 lirpA ,yadsendeW
1.5A, LOW NOISE, NEGATIVE REGULATOR
KT
EDWIN L.
N/A
DEMO CIRCUIT 1728A
WITH PRECISION CURRENT LIMIT
SIZE
DATE:
.VER.ON CI
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: (408)434-0507
Milpitas, CA 95035
Phone: (408)432-1900
1630 McCarthy Blvd.
LTC Confidential-For Customer Use Only
CUSTOMER NOTICE
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.
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
SCALE = NONE
www.linear.com
1
LT3015EDD
111102 ,02 lirpA ,yadsendeW
1.5A, LOW NOISE, NEGATIVE REGULATOR
KT
EDWIN L.
N/A
DEMO CIRCUIT 1728A
WITH PRECISION CURRENT LIMIT
SIZE
DATE:
.VER.ON CI
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: (408)434-0507
Milpitas, CA 95035
Phone: (408)432-1900
1630 McCarthy Blvd.
LTC Confidential-For Customer Use Only
CUSTOMER NOTICE
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.
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
SCALE = NONE
www.linear.com
1
LT3015EDD
111102 ,02 lirpA ,yadsendeW
1.5A, LOW NOISE, NEGATIVE REGULATOR
KT
EDWIN L.
N/A
DEMO CIRCUIT 1728A
WITH PRECISION CURRENT LIMIT
REVISION HISTORY
DESCRIPTION DATEAPPROVEDECO REV
EDWIN L.
PRODUCTION
104-20-11
_
REVISION HISTORY
DESCRIPTION DATEAPPROVEDECO REV
EDWIN L.
PRODUCTION
104-20-11
_
REVISION HISTORY
DESCRIPTION DATEAPPROVEDECO REV
EDWIN L.
PRODUCTION
104-20-11
_
R3
3.65k
R3
3.65k
R2
0
R2
0
R1
3.48k
R1
3.48k
E3E3
COUT
10uF
25V
1206
COUT
10uF
25V
1206
R4
11.0k
R4
11.0k
CIN
10uF
50V
1210
CIN
10uF
50V
1210
RSD
0
RSD
0
R7
OPT
R7
OPT
E5E5
JP1JP113 2
4
U1
LT3015EDD
U1
LT3015EDD
GND
5
IN
1
ADJ 6
OUT 8
IN
2
SHDN
3
GND
4
OUT 7
IN 9
E1E1
+
C1
10uF
50V
+
C1
10uF
50V
R6
39.2k
R6
39.2k
+
C2
7343
OPT
+
C2
7343
OPT
JP2
HD2X6-079
JP2
HD2X6-079
1
3
5 6
4
2
7
98
10
11 12
E4E4
E2E2
R9
100k
R9
100k
R5
30.9k
R5
30.9k
R8
OPT
R8
OPT
6
dc1728af
DEMONSTRATION CIRCUIT
1728A QUICK START GUIDE
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com
© LINEAR TECHNOLOGY CORPORATION 2011
LT 0611 • 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 applica-
tion engineer.
Mailing Address:
Linear Technology
1630 McCarthy Blvd.
Milpitas, CA 95035
Copyright © 2004, Linear Technology Corporation
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Linear Technology LT3015 Quick start guide
- Category
- Voltage regulators
- Type
- Quick start guide
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