Linear Technology DC1238B User manual

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dc1238bf
DEMO MANUAL DC1238B
DESCRIPTION
LTM8021
36V, 500mA Step-Down
µModule Regulator
Demonstration circuit 1238B features the LTM
®
8021, a
36V500mAstep-downμModule
®
regulator. The output has
been preset to 5V by a single resistor within the LTM8021’s
output voltage range of 0.8V to 5V. An adjustable soft-start
period may be implemented with the addition of a capaci-
tor at C3. The input voltage range is from 7.5V to 36V for
the default operating conditions. The LTM8021 may need
more input voltage to start up than to run in steady state. L, LT, LTC, LTM, μModule, 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
BOARD PHOTO
The data sheet gives a complete description of the part,
operation and applications information. The LTM8021 data
sheet must be read in conjunction with this demo manual
prior to working on or modifying demo circuit DC1238B.
Design files for this circuit board are available at
http://www.linear.com/demo
(TA= 25°C)
PARAMETER CONDITIONS VALUE
Input Voltage Range VOUT = 5V 7.5V to 36V
Output Voltage VIN = 12V, ILOAD = 500mA, R1 = 19.1k 5V ±3%
Maximum Continuous Output Current 500mA
Switching Frequency 1.1MHz
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DEMO MANUAL DC1238B
QUICK START PROCEDURE
Demonstration circuit 1238 is an easy way to evaluate the
performance of the LTM8021. 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 VIN or
VOUT and GND terminals. See Figure 2 for proper scope
probe technique.
1. Place JP1 on the ON position.
2. With power off, connect the input power supply to VIN
and GND.
3. Turn on the power at the input.
NOTE. Make sure that the input voltage does not exceed
the maximum rated input voltage of the LTM8021.
4. Check for the proper output voltage. VOUT = 5V ±3%
NOTE. If there is no output, temporarily disconnect the
load to make sure that the load is not set too high.
5. Once the proper output voltage is established, adjust
the load within the operating range and observe the
output voltage regulation, ripple voltage, efficiency and
other parameters.
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DEMO MANUAL DC1238B
Figure 2. Measuring Input or Output Voltage Ripple
Figure 1. Proper Measurement Equipment Setup
GND VIN
dc1238b F02
QUICK START PROCEDURE
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DEMO MANUAL DC1238B
PARTS LIST
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
Required Circuit Components
1 1 C2 CAP., X5R, 4.7μF, 6.3V, 10%, 0603 AVX, 06036D475KAT2A
2 1 C1 CAP., X7R, 1μF, 50V, 10%, 0805 MURATA, GRM21BR71H105K
3 1 R1 RES., CHIP, 19.1k, 1/16W, 1% ,0402 VISHAY, CRCW040219K1FKED
4 1 R2 RES., CHIP, 0Ω, 1/16W, 1% ,0603 VISHAY, CRCW06030000Z0ED
5 1 R3 RES., CHIP, 51.1k 1/16W, 1% ,0603 VISHAY, CRCW060351K1FKED
6 1 U1 I.C., LTM8021EV#PBF, LGA, 15 PIN LINEAR TECH., LTM8021EV#PBF
Additional Demo Board Circuit Components
1 1 C4 CAP., SMT, 10μF, 50V SANYO, 50CE10BSS
2 0 C3, C5 (OPT) CAP., 0603
Hardware For Demo Board Only
1 1 E1, E3-E7 TESTPOINT, TURRET, 0.095" MILL-MAX, 2501-2-00-80-00-00-07-0
2 1 JP1 2MM SINGLE ROW HEADER, 3 PIN SAMTEC, TMM-103-02-L-S
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DEMO MANUAL DC1238B
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 B B A A
7.5V - 36V
ON
OFF
5V / 500mA
*
* SEE QUICK START GUIDE
1. ALL RESISTORS ARE 0603. ALL CAPACITORS ARE 0603. NOTE: UNLESS OTHERWISE SPECIFIED
0805
50V
REVISION HISTORY DESCRIPTION DATEAPPROVEDECO REV
MOLLY Z.
PRODUCTION
14-9-121
REVISION HISTORY DESCRIPTION DATEAPPROVEDECO REV
MOLLY Z.
PRODUCTION
14-9-121
REVISION HISTORY DESCRIPTION DATEAPPROVEDECO REV
MOLLY Z.
PRODUCTION
14-9-121
SIZE DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY
Fax: [phone] Milpitas, CA 95035 Phone: [phone] 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
Wednesday, June 13, 2012
11
36V, 500mA STEP-DOWN DC/DC μMODULE
HZ
MOLLY Z.
N/A
LTM8021EV
DEMO CIRCUIT 1238B
SIZE DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY
Fax: [phone] Milpitas, CA 95035 Phone: [phone] 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
Wednesday, June 13, 2012
11
36V, 500mA STEP-DOWN DC/DC μMODULE
HZ
MOLLY Z.
N/A
LTM8021EV
DEMO CIRCUIT 1238B
SIZE DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY
Fax: [phone] Milpitas, CA 95035 Phone: [phone] 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
Wednesday, June 13, 2012
11
36V, 500mA STEP-DOWN DC/DC μMODULE
HZ
MOLLY Z.
N/A
LTM8021EV
DEMO CIRCUIT 1238B
C5
(OPT)
C5
(OPT)
C1
1uF
C1
1uF E4 VOUT
E4 VOUT
C2
4.7uF
C2
4.7uF
R2
0
R2
0
E7
GND E7 GND
JP1JP1
1
2
3
E5 BIAS E5 BIAS
R3
51.1K
R3
51.1K
+
C4
10uF
+
C4
10uF
U1
LTM8021EV
U1
LTM8021EV
VIN
A4
VIN
A5
VIN
B4
VIN
B5
ADJ
A2
RUN/SS
A1
GND
B1
GND
B2
GND
C1
GND
C2
GND
D1
GND
D2
GND
D3
GND
D4
GND
D5
GND
E1
GND
E2
GND
E3
GND
E4
GND
E5
GND
F1
GND
F2
GND
G1
GND G2 GND H1 GND H2
VOUT F3 VOUT F4 VOUT F5
VOUT G3
VOUT G4
VOUT G5
VOUT H4
VOUT H5
BIAS H3
E6 GND E6 GND
E1
VIN E1 VIN
E3
RUN/SS E3 RUN/SS
C3
(OPT)
C3
(OPT)
R1
19.1K
0402
R1
19.1K
0402
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DEMO MANUAL DC1238B
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
[phone] ●FAX: [phone] ●www.linear.com
© LINEAR TECHNOLOGY CORPORATION 2012
LT 0612 • 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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