Linear Technology DC2072A Quick setup guide

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DEMO MANUAL DC2072A
Description
LT3065
45V, 500mA Low Noise Linear Regulator with
Programmable Current Limit and Power Good
Demonstration circuit 2072A is an adjustable 500mA
linear regulator featuring the LT
®
3065. The LT3065 is a
micropower, low noise and low dropout voltage linear
regulator. The device supplies 500mA of output current
with a typical dropout voltage of 300mV. A 10nF bypass
capacitor reduces output noise to 25µVRMS in a 10Hz
to 100kHz bandwidth and soft-starts the reference. The
LT3065’s ±45V input voltage rating combined with its
precision current limit make the IC an ideal choice for
robust, high reliability applications.
LT3065 current limit can be programmed by a single
resistor, accurate to ±10% over a wide input voltage and
temperature range. The internal current limit should be
considered when the input-to-output differential is high.
The LT3065 has a PWRGD pin, which becomes high
when the output rises above 90% of its nominal value.
If the output falls below 88.4% of its nominal value for
more than 25µs, the PWRGD pin asserts low. The use of
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
a feedforward cap may cause the PWRGD flag to assert
early during a startup transient. To avoid this, ensure
that the REF/BYP capacitor is significantly larger than the
feedforward capacitor.
LT3065 optimizes stability and transient response with
low ESR ceramic capacitors, requiring a minimum
capacitance of 3.3µF.
The LT3065 is available in the thermally-enhanced 10-lead
3mm × 3mm DFN and 12-lead MSOP packages.
The LT3065 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 DC2072A.
Design files for this circuit board are available at
http://www.linear.com/demo/DC2072A
Specifications are at TA= 25°C
PARAMETER CONDITIONS MIN TYP MAX UNITS
Input Voltage Range VOUT = 5V 5.35 45 V
Output Voltage VOUT Header in JP1
Header in JP2
Header in JP3
Header in JP4
Header in JP5
Header in JP6
Header in JP7
1.176
1.46
1.75
1.94
2.43
3.23
4.85
1.2
1.5
1.8
1.99
2.5
3.32
4.99
1.22
1.54
1.74
2.04
2.57
3.41
5.13
V
V
V
V
V
V
V
Maximum Output Current VIN = 6V, VOUT = 5V, R10 = 604Ω 445 495 545 mA
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DEMO MANUAL DC2072A
Quick start proceDure
DC2072A is easy to set up to evaluate the performance of
the LT3065. Refer to Figure 1 for the proper measurement
equipment setup and follow the procedure below:
NOTE:Makesurethattheinputvoltagedoesnotexceed45V.
NOTE: The shutdown jumper JP2 shunt is required to be
placed in the OFF or ON position for proper operation.
NOTE: Place the output voltage selection jumper JP1 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
voltage selection jumper JP1. If the output voltage is
different from the above values, use the USER option
and install R8. Select R8 according to the following
equation:
R8 = (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. Oncethe proper outputvoltage is established,adjust the
load within the operating range and observe the output
voltage regulation, PWRGD and other parameters.
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DEMO MANUAL DC2072A
Quick start proceDure
Figure 1. Proper Measurement Equipment Setup
Figure 2. Measuring Input or Output Ripple
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DEMO MANUAL DC2072A
parts List
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
Required Circuit Components
1 1 C2 CAP., X7R, 10µF, 50V, 10% 1210 MURATA, GRM32ER71H106KA12L
2 2 C3, C4 CAP., X7R, 4.7µF, 50V, 10% 1210 MURATA, GRM32ER71H475KA88L
3 1 C5 CAP., X7R, 0.01µF, 16V, 20% 0603 AVX, 0603YC103MAT2A
4 1 C6 CAP., X7R, 1nF, 16V, 20% 0603 AVX, 0603YC102MAT2A
5 1 C7 CAP., X7R, 0.022µF,16V, 20% 0402 AVX, 0402YC223KMAT2A
6 2 R1, R9 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, 140k, 0.06W, 1% 0402 VISHAY, CRCW0402140KFKED
10 1 R5 RES., CHIP, 191k, 0.06W, 1% 0402 VISHAY, CRCW0402191KFKED
11 1 R6 RES., CHIP, 274k, 0.06W, 1% 0402 VISHAY, CRCW0402274KFKED
12 1 R7 RES., CHIP, 442k, 0.06W, 1% 0402 VISHAY, CRCW0402442KFKED
13 1 R10 RES., CHIP, 604Ω, 0.06W, 1% 0603 VISHAY, CRCW0603604RFKEA
14 1 R12 RES., CHIP, 499k, 0.06W, 1% 0603 VISHAY, CRCW0603499KFKEA
15 1 U1 I.C., MICROPOWER LDO DFN-10-3X3 LINEAR TECH., LT3065EDD
Additional Demo Board Circuit Components
1 1 C1 CAP., ALUM., 22µF, 50V, CE-BSS SERIES SUN SELECT., 50CE22BSS
2 0 R8, R11 (OPT) RES., 0603
Hardware: For Demo Board Only
1 6 E1-E6 TESTPOINT, TURRET, .094" PBF MILL-MAX, 2501-2-00-80-00-00-07-0
2 1 JP1 HEADERS, 2 × 8 (2mm Ctrs.) SAMTEC, TMM-108-02-L-D
3 1 JP2 HEADERS, 3 PINS 2mm Ctrs. SULLINS, NRPN031PAEN-RC
4 2 XJP1, XJP2 SHUNT, .079" CENTER SAMTEC, 2SN-BK-G
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DEMO MANUAL DC2072A
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
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DEMO MANUAL DC2072A
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
[phone] ●FAX: [phone] ●www.linear.com
 LINEAR TECHNOLOGY CORPORATION 2014
LT 0214 • 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
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agency certified (FCC, UL, CE, etc.).
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Mailing Address:
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Copyright © 2004, Linear Technology Corporation
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