LT8303
100V Micropower Isolated
IN
Flyback Converter with
150V/450mA Switch
DescripTion
FeaTures
TheLT®8303isamicropowerhighvoltageisolatedflyback
converter. By sampling the isolated output voltage directly
from the primary-side flyback waveform, the part requires
nothirdwindingoropto-isolatorforregulation.Theoutput
voltage is programmed with a single external resistor.
Internalcompensationandsoft-startfurtherreduceexternal
component count. Boundary mode operation provides a
small magnetic solution with excellent load regulation.
LowrippleBurstModeoperationmaintainshighefficiency
at light load while minimizing the output voltage ripple.
A 450mA, 150V DMOS power switch is integrated along
withallhighvoltagecircuitryandcontrollogicintoa5-lead
ThinSOT™ package.
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5.5V to 100V Input Voltage Range
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450mA, 150V Internal DMOS Power Switch
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Up to 5W of Output Power
Low Quiescent Current:
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70µA in Sleep Mode
280µA in Active Mode
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Boundary Mode Operation at Heavy Load
Low Ripple Burst Mode® Operation at Light Load
Minimum Load <0.5% (Typ) of Full Output
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V
Set with a Single External Resistor
OUT
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No Transformer Third Winding or Opto-Isolator
Required for Regulation
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Accurate EN/UVLO Threshold and Hysteresis
Internal Compensation and Soft-Start
5-Lead TSOT-23 Package
The LT8303 operates from an input voltages range of 5.5V
to 100V and can deliver up to 5W of isolated output power.
Thehighlevelofintegrationandtheuseofboundarymode
and low ripple Burst Mode operations result in a simple to
use, lowcomponentcount, andhighefficiencyapplication
solution for isolated power delivery.
applicaTions
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Isolated Telecom, Datacom, Automotive, Industrial,
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. Protected by U.S. Patents, including 5438499, 7463497,
and 7471522.
and Medical Power Supplies
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Isolated Auxiliary/Housekeeping Power Supplies
Typical applicaTion
6V to 80VIN, 5VOUT Isolated Flyback Converter
Efficiency vs Load Current
100
+
T1
6:1
V
V
OUT
IN
5V
6V TO 80V
90
•
4.7µF
150µH
4.2µH
V
IN
100µF
80
70
60
50
40
•
LT8303
EN/UVLO
–
SW
V
OUT
316k
2.5mA TO 0.33A (V = 12V)
IN
2.5mA TO 0.52A (V = 24V)
R
IN
IN
IN
FB
V
V
V
V
= 12V
= 24V
= 48V
= 72V
IN
IN
IN
IN
2.5mA TO 0.73A (V = 48V)
GND
2.5mA TO 0.84A (V = 72V)
8303 TA01a
0
100 200 300 400 500 600 700 800 900
LOAD CURRENT (mA)
8303 TA01b
8303fa
For more information www.linear.com/LT8303
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