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Description
Demonstration circuit 2138A is an isolated flyback con-
verter 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 V
= 24V.
IN
The Performance Summary table summarizes the perfor-
mance 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
Input Voltage
Standby Current
Output Voltage
Maximum Output Current
Output Voltage Ripple (Peak to Peak)
Switching Frequency
Efficiency
DEMO MANUAL DC2138A
42V
Micropower Isolated Flyback
IN
Converter with 65V/1.2A Switch
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. Bound-
ary 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 T
CONDITIONS
IOUT = 0mA, VIN = 24V, VOUT = 5V
VIN = 12V to 32V, IOUT = 6mA to 700mA
VIN = 12V
VIN = 24V
VIN = 24V, IOUT = 1A
VIN = 24V, IOUT = 1A
VIN = 24V, IOUT = 1A
= 25°C
A
MIN
TYP
10
950
4.75
700
1000
190
83.2
LT8301
®
MAX
UNITS
24
32
V
µA
5
5.25
V
mA
mA
90
mV
kHz
%
dc2138af
1
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Related Manuals for Linear Technology DC2138A
Summary of Contents for Linear Technology DC2138A
- Page 1 Zener is optional, and can be replaced with a 0.8k resistor. 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 The LT8301 is a simple-to-use high-voltage monolithic property of their respective owners.
-
Page 2: Quick Start Procedure
DEMO MANUAL DC2138A Quick start proceDure Demo circuit 2138A is easy to set up to evaluate the 3. Check for the proper output voltages. The output should performance of the LT8301. Refer to Figure 1 for proper be regulated at 5V (±5%). - Page 3 DEMO MANUAL DC2138A Quick start proceDure INPUT OR OUTPUT CAPACITOR Figure 2. Proper Scope Probe Placement for Measuring Input or Output Ripple = 12V = 24V = 32V LOAD CURRENT (A) dc2138a F03 Figure 3. Typical Efficiency Curves 5.25 5.20 5.15...
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Page 4: Parts List
DEMO MANUAL DC2138A parts List ITEM REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER Required Circuit Components CAP., ALUM., 22µF, 50V SUN ELECT., 50CE22BS CAP., X7R, 10µF, 50V, 10%, 1210 MURATA, GRM32ER71H106KA12L CAP., X5R, 100µF, 6.3V, 20%, 1210 MURATA, GRM32ER6J107ME20L DIODE, PMEG3020EH, SOD-123 NXP, PMEG3020EH DIODE, 5.6V, SOD-523... -
Page 5: Schematic Diagram
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. - Page 6 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.
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