DC2138A - Demo Manual

DEMO MANUAL DC2138A
LT8301
42VIN Micropower Isolated Flyback
Converter with 65V/1.2A Switch
Description
Demonstration circuit 2138A is an isolated flyback converter featuring the LT8301. This demo circuit outputs
5V from a 10V to 32V input, with a nominal of 24V. The
output current capability increases with the input voltage.
The standby input current of the demo circuit is less than
950µA (typical) at VIN = 24V.
The Performance Summary table summarizes the performance of the demo board at room temperature. The demo
circuit can be easily modified for different applications with
some pre-designed transformers.
The DC2138A needs a very small minimum load (~6mA)
to regulate the output voltage, thanks to the accurate
current limit capability and ultralow switching frequency
of LT8301 at very light load. On the board, a Zener diode
is placed on the output to clamp the voltage to ~5V. This
Zener is optional, and can be replaced with a 0.8k resistor.
The LT8301 is a simple-to-use high-voltage monolithic
isolated flyback converter. No third winding or opto-isolator
Performance Summary
PARAMETER
is required for regulation. The part sets the isolated output
voltage with a single external resistor and integrates loop
compensation and soft-start circuitry inside the IC. Boundary mode operation provides a small magnetic solution
with improved load regulation. Low-ripple Burst Mode®
operation maintains high efficiency at light loads while
minimizing the output voltage ripple. A 1.2A, 65V DMOS
power switch is integrated along with all high-voltage
circuitry and control logic into a 5-lead ThinSOT™ package.
The LT8301 data sheet gives a complete description of
the part, operation and application information. The data
sheet must be read in conjunction with this quick start
guide for demo circuit 2138A.
Design files for this circuit board are available at
http://www.linear.com/demo/DC2138A
L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks
and ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners.
Specifications are at TA = 25°C
CONDITIONS
Input Voltage
Standby Current
MIN
TYP
MAX
10
24
32
IOUT = 0mA, VIN = 24V, VOUT = 5V
950
5
UNITS
V
µA
Output Voltage
VIN = 12V to 32V, IOUT = 6mA to 700mA
4.75
Maximum Output Current
VIN = 12V
VIN = 24V
700
1000
5.25
V
Output Voltage Ripple (Peak to Peak)
VIN = 24V, IOUT = 1A
90
mV
Switching Frequency
VIN = 24V, IOUT = 1A
190
kHz
Efficiency
VIN = 24V, IOUT = 1A
83.2
%
mA
mA
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DEMO MANUAL DC2138A
Quick Start Procedure
Demo circuit 2138A is easy to set up to evaluate the
performance of the LT8301. Refer to Figure 1 for proper
equipment setup and follow the procedure below.
1.With power off, connect the input power supply to the
board through VIN and GND terminals. Connect the
load to the terminals VOUT+ and VOUT– on the board.
2.Turn on the power at the input. Increase VIN slowly to
10V.
NOTE. Make sure that the input voltage is always within
spec. To operate the board with higher input/output
voltage, input capacitor, output capacitor and output
diode with higher voltage ratings are needed.
NOTE. To run overload tests on the demo board at high
line, additional RC snubber might be needed to make
sure the voltage spike at the switching node is always
less than 65V.
3.Check for the proper output voltages. The output should
be regulated at 5V (±5%).
NOTE. The LT8301 requires very small minimum load
to maintain good output voltage regulation. A Zener
diode is placed on the output to clamp the voltage to
~5V. This Zener is optional, and can be replaced with
a 0.8k resistor.
4.Once the proper output voltage is established, adjust
the input voltage and load current within the operating
range and observe the output voltage regulation, transient, ripple voltage, efficiency and other parameters.
NOTE. When measuring the input or output voltage
ripples, 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 capacitor terminals. See Figure 2 for
proper scope probe technique.
Figure 1. Proper Measurement Equipment Setup
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DEMO MANUAL DC2138A
Quick Start Procedure
INPUT OR OUTPUT CAPACITOR
Figure 2. Proper Scope Probe Placement for Measuring Input or Output Ripple
90
EFFICIENCY (V)
85
80
75
70
VIN = 12V
VIN = 24V
VIN = 32V
65
60
0
0.2
0.6
0.4
LOAD CURRENT (A)
0.8
1.0
dc2138a F03
Figure 3. Typical Efficiency Curves
5.25
5.20
5.15
VOUT (V)
5.10
5.05
5.00
4.95
4.90
4.85
VIN = 12V
VIN = 24V
VIN = 32V
4.80
4.75
0.006
0.206
0.606
0.406
0.806
LOAD CURRENT (A)
dc2138a F04
Figure 4. Typical Regulation Curves
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DEMO MANUAL DC2138A
Parts List
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
CAP., ALUM., 22µF, 50V
SUN ELECT., 50CE22BS
Required Circuit Components
1
1
Cin
2
1
C1
CAP., X7R, 10µF, 50V, 10%, 1210
MURATA, GRM32ER71H106KA12L
3
1
C2
CAP., X5R, 100µF, 6.3V, 20%, 1210
MURATA, GRM32ER6J107ME20L
4
1
D1
DIODE, PMEG3020EH, SOD-123
NXP, PMEG3020EH
5
1
D2
DIODE, 5.6V, SOD-523
DIODES., BZT52C5V6T-7-F
6
1
D3
DIODE., 1N4148WS, SOD323
DIODES., 1N4148WS-7-F
7
1
D4
DIODE, CMHZ5248B, SOD-123
CENTRAL., CMHZ5248B
8
1
R1
RES., CHIP, 1M, 1/8W, 1% 0805
VISHAY, CRCW08051M00FKEA
9
1
R2
RES., CHIP, 210k, 1/10W, 1% 0603
VISHAY, CRCW0603210KFKEA
10
1
R3
RES., CHIP, 154k, 1/10W, 1% 0603
VISHAY, CRCW0603154KFKEA
11
1
T1
TRANSFORMER, 750313974
WURTH, 750313974
12
1
U1
I.C. FLYBACK CONVERTER, SOT23-5
LINEAR TECH., LT8301ES5#PBF
CAP., X7R, 0.22µF, 6.3V, 10%, 0603
MURATA, GRM188R70J224KA
Additional Demo Board Circuit Components
1
0
C3 (OPT)
2
0
C4 (OPT)
CAP., X7R, 0.01µF, 50V, 10%, 0603
AVX, 06035C103KAT2A
3
0
C5 (OPT)
CAP., X7R, 4.7µF, 50V, 10%, 1210
AVX, 12105C475KAT2A
4
0
C6 (OPT)
CAP., ALUM., 22µF, 50V
SUN ELECT., 50CE22BS
5
0
C7
CAP., X7R, 3300pf, 500V, 10% 1210
AVX, 12107C332KAT2A
6
0
FB1 (OPT)
BEAD, 1206
TAIYO YUDEN, MJ3216HS800
7
0
L1 (OPT)
IND., 10µH
SUMIDA, CDRH4D22HPNP-100MC
8
0
R4 (OPT)
RES., CHIP, 2.21k, 1/8W, 1% 0805
VISHAY, CRCW080512K21FKEA
Hardware: For Demo Board Only
1
5
E1-E5
TESTPOINT, TURRET, 0.094" pbf
MILL-MAX, 2501-2-00-80-00-00-07-0
2
1
JP1
3 PIN 0.079" SINGLE ROW HEADER
SAMTEC, TMM103-02-L-S
3
1
XJP1
SHUNT, 0.079" CENTER
SAMTEC, 2SN-BK-G
dc2138af
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E2
R2
210K
R1
1M
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.
1. ALL RESISTORS AND CAPACITORS ARE 0603.
NOTE: UNLESS OTHERWISE SPECIFIED
E5
EN/UVLO
JP1
1
EN
2
3
DIS
GND
50CE22BS
22uF
50V
+Cin
C1
10uF
50V
1210
3
2
1
SW
VIN
R3 154K
RFB
GND
EN/UV
U1
LT8301ES5
4
5
SW
2
1
1
2
D3
1N4148WS
CMHZ5248B
D4
R4
OPT
C3
OPT
C7
3.3nF
VIN
1210
250V
7
1
8
6
4
5
C4
0.01uF,50V
0603
C5
4.7uF,50V
1210
+
SUMIDA
CDRH4D22/HP
L1
10UH
VOUT+
C6
22uF,50V
50CE22BS
VIN
VOUT-
[email protected], VIN>12V
[email protected], VIN>24V
E4
E3
D2
BZT52C5V6T-7
5.6V
OPTIONAL CIRCUIT
C2
100uF
6.3V
1210
D1
PMEG3020EH
1
2
TAIYO YUDEN
FB MJ3216HS800
FB1
BEAD
WURTH, 750313974
T1
1
2
VIN
E1
10V - 32V
VIN
DEMO MANUAL DC2138A
Schematic Diagram
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DEMO MANUAL DC2138A
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 0314 • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507 ● www.linear.com
 LINEAR TECHNOLOGY CORPORATION 2014
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