Linear Technology DC1865A Quick setup guide

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DEMO MANUAL DC1865A
Description
LT3055
500mA, Linear Regulator with
Precision Current Limit and Diagnostics
Demonstrationcircuit1865Aisanadjustable500mAlinear
regulator featuring LT
®
3055. LT3055 is a micropower, low
noise and low dropout voltage linear regulator. The device
supplies 500mA of output current with a dropout voltage
of 350mV. A 10nF bypass capacitor reduces output noise
to 25µVRMS in a 10Hz to 100kHz bandwidth and soft-starts
the reference. The LT3055’s ±45V input voltage rating
combined with its precision current limit and diagnostic
functions make the IC an ideal choice for robust, high
reliability applications.
LT3055 current limit can be programmed by a single
resistor, accurate to ±10% over a wide input voltage
and temperature range. Another resistor programs the
LT3055’s minimum output current monitor, useful for
detectingopen-circuitconditions.The internal current limit
should be considered when the input-to-output differential
is high. The current monitor function sources a current
equal to 1/500th of output current. See the Operation sec- 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
tion in the data sheet for a detailed calculation. Logic fault
pins assert low if the LT3055 is in current limit (FAULT2),
operating below its minimum output current (FAULT1)
or is in thermal limit (both FAULT1 and FAULT2). The die
temperature is indicated by the TEMP pin.
LT3055 optimizes stability and transient response with a
low ESR ceramic capacitor, requiring a minimum of 3.3µF.
The LT3055 is available in the thermally-enhanced 16-lead
4mm × 3mm DFN and MSOP packages.
The LT3055 data sheet gives a complete description of
the device, operation and application information. The
data sheet must be read in conjunction with this quick
start guide for DC1865.
Design files for this circuit board are available at
http://www.linear.com/demo/DC1865A
PARAMETER CONDITIONS VALUE
Minimum Input Voltage (Max) VOUT = 5V, IOUT = 500mA 5.6V
Maximum Input Voltage VOUT = 5V 45V
Output Voltage VOUT Header in JP1
Header in JP2
Header in JP3
Header in JP4
Header in JP5
Header in JP6
1.20V ±3%
1.50V ±3%
1.80V ±3%
2.50V ±3%
3.32V ±3%
4.99V ±3%
Maximum Output Current (Typ) VIN = 12V, VOUT = 5V, R10 = 604Ω 500mA
Minimum Output Current (Typ) VIN = 12V, VOUT = 5V, R9 = 121kΩ 10mA
IMON Voltage (to µP ADC) (Typ) VIN = 12V, VOUT = 5V, R8 = 1k, IOUT = 500mA 1V
Temp voltage (Typ) VIN = 12V, VOUT = 5V 0.25V
Specifications are at TA= 25°C
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DEMO MANUAL DC1865A
Quick start proceDure
DC1865A is easy to set up to evaluate the performance
of the LT3055. Refer to Figure 1 for proper measurement
equipment setup and follow the procedure below:
NOTE:Makesurethattheinputvoltagedoes not exceed 45V.
NOTE: The shutdown jumper JP8 shunt is required to be
placed in the OFF or ON position for proper operation.
NOTE: Place the output voltage selection jumper JP1-JP7
at the desired position.
NOTE: Do not hot-plug the input voltage terminal VIN. The
absolute maximum voltage on VIN is 50V and hot-plugging
a power supply through wire leads to the demonstration
circuit can cause the voltage on the extremely low-ESR
ceramic input capacitor to ring to twice its DC value. In
order to protect the IC, a higher ESR Aluminum Electro-
lytic capacitor is placed at the input terminals. This may
protect against some, but not all, input transients due to
hot-plugging with a power supply. See Application Note
88 for more details.
NOTE: Connect the power supply (with power off), load,
and meters as shown in Figure 1.
1. After all connections are made, turn on input power and
verify that the output voltage according to the output
voltageselectionjumper(JP1-JP7).If theoutputvoltage
is different from the above values, use the USER option
and install R7. Select R7 according to the following
equation:
R7 = (VOUT/0.6 – 1) • 60.4k
NOTE: If the output voltage is too low, temporarily
disconnect the load to make sure that the load is not
set too high.
2. Once the proper output voltage is established, adjust
the load within the operating range and observe the
output voltage regulation, FAULT1, FAULT2, PWRGD
and other parameters.
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DEMO MANUAL DC1865A
Quick start proceDure
Figure 1. Proper Measurement Equipment Setup
Figure 2. Measuring Input or Output Ripple
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DEMO MANUAL DC1865A
parts List
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
Required Circuit Components
1 2 C1, C8 Cap., X7R, 0.01µF, 16V, 10% 0603 AVX, 0603YC103KAT2A
2 2 C2, C3 Cap., X5R, 0.1µF, 16V, 20% 0402 AVX, 0402YD104MAT2A
3 1 C4 Cap., X7R, 22nF, 16V, 10% 0402 AVX, 0402YC223KAT2A
4 2 C5, C6 Cap., X7R, 10µF, 50V, 10% 1210 TAIYO YUDEN, UMK325AB7106KM-T
5 1 C9 Cap., X7R, 100pF, 16V, 10% 0402 AVX, 0402YC101KAT2A
6 2 R1, R12 Res., Chip, 60.4k, 0.06W, 1% 0402 VISHAY, CRCW040260K4FKED
7 1 R2 Res., Chip, 90.9k, 0.06W, 1% 0402 VISHAY, CRCW040290K9FKED
8 1 R3 Res., Chip, 121k, 0.06W, 1% 0402 VISHAY, CRCW0402121KFKED
9 1 R4 Res., Chip, 191k, 0.06W, 1% 0402 VISHAY, CRCW0402191KFKED
10 1 R5 Res., Chip, 274k, 0.06W, 1% 0402 VISHAY, CRCW0402274KFKED
11 1 R6 Res., Chip, 442k, 0.06W, 1% 0402 VISHAY, CRCW0402442KFKED
12 1 R8 Res., Chip, 1.00k, 0.1W, 1% 0603 VISHAY, CRCW06031K00FKEA
13 1 R9 Res., Chip, 121k, 0.1W, 1% 0603 VISHAY, CRCW0603121KFKEA
14 1 R10 Res., Chip, 604Ω, 0.1W, 1% 0603 VISHAY, CRCW0603604RFKEA
15 3 R11, R13, R14 Res., Chip, 499k, 0.1W, 1% 0603 VISHAY, CRCW0603499KFKEA
16 1 U1 I.C., Volt. Reg., DFN-16 (4×3) LINEAR TECH., LT3055EDE#PBF
Additional Demo Board Circuit Components
1 1 CIN Cap., Alum., 22µF, 50V, 6.3mm × 5.4mm SUN SELECT, 50CE22BSS
2 0 C7 (OPT) Cap., D Case
3 0 R7 (OPT) Res., 0603
Hardware-For Demo Board Only
1 9 E1-E9 Turret, Testpoint 0.094" MILL-MAX 2501-2-00-80-00-00-07-0
2 7 JP1-JP7 Headers, 2 Pins 2mm Ctrs. SAMTEC, TMM-102-02-L-S
3 1 JP8 Headers, Single Row 3 Pins 2mm Ctrs. SAMTEC, TMM-103-02-L-S
4 2 XJP6, XJP8 Shunt, 2mm Ctrs. SAMTEC, 2SN-BK-G
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DEMO MANUAL DC1865A
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
1. ALL RESISTORS ARE 0402. ALL CAPACITORS ARE 0402. NOTE: UNLESS OTHERWISE SPECIFIED
C1 0.01uF
0603
C1 0.01uF
0603
R10 604
1%
0603 R10 604
1%
0603
JP5
3.3V
JP5
3.3V
JP2
1.5V
JP2
1.5V
R4
191K 1%
R4
191K 1%
JP6
5V
JP6
5V
E2
GND
E2
GND
E8
PWRGD
E8
PWRGD
C5
10uF
50V
1210
C5
10uF
50V
1210
JP7
USER SELECT
JP7
USER SELECT
R5
274K 1%
R5
274K 1%
R12
60.4K 1%
R12
60.4K 1%
R6
442K 1%
R6
442K 1%
R8
1.00K 1% 0603
R8
1.00K 1% 0603
C9 0.1nF C9 0.1nF
JP1 1.2V JP1 1.2V
R2
90.9K 1%
R2
90.9K 1%
E7
TEMP
E7
TEMP
E6
IMON
E6
IMON
R13
499K 1%
0603
R13
499K 1%
0603
R9
121k 1%
0603 R9
121k 1%
0603
E4 GND E4 GND
R3
121K 1%
R3
121K 1%
E3
VOUT
500mA
E3
VOUT
500mA
E5
FAULT1
E5
FAULT1
C8 0.01uF
0603
C8 0.01uF
0603
R7 OPT
0603
R7 OPT
0603
C6
10uF 50V
1210
C6
10uF 50V
1210
R11
499K 1%
0603
R11
499K 1%
0603
R1
60.4K 1%
R1
60.4K 1%
JP8
ON OFF
SHDN
JP8
ON OFF
SHDN
1 3 2
U1
LT3055EDE
U1
LT3055EDE
REF/BYP
11
IMIN
9
IMON
8
IN
2
FAULT1
4
GND
17
SHDN
3
IN
1
OUT
15
OUT
16
ADJ
14
GND
12
IMAX
10
FAULT2
5
PWRGD
6
TEMP
7
GND
13
C4
22nF
C4
22nF
JP3
1.8V
JP3
1.8V
C3
0.1uF
C3
0.1uF
+
C7
OPT
"D" Case
+
C7
OPT
"D" Case
E9
FAULT2
E9
FAULT2
E1
VIN
2.2V - 45V E1
VIN
2.2V - 45V
C2 0.1uF C2 0.1uF
+
CIN
22uF 50V
+
CIN
22uF 50V
R14
499K 1%
0603
R14
499K 1%
0603
JP4
2.5V
JP4
2.5V
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DEMO MANUAL DC1865A
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
[phone] ●FAX: [phone] ●www.linear.com
 LINEAR TECHNOLOGY CORPORATION 2013
LT 0613 • PRINTED IN USA
DEMONSTRATION BOARD IMPORTANT NOTICE
Linear Technology Corporation (LT C ) 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 LT C 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 LT C 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. LT C assumes no liability for applications assistance,
customer product design, software performance, or infringement of patents or any other intellectual property rights of any kind.
LT C 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 LT C applica-
tion engineer.
Mailing Address:
Linear Technology
1630 McCarthy Blvd.
Milpitas, CA 95035
Copyright © 2004, Linear Technology Corporation
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