LT8302/LT8302-3
42V Micropower No-Opto
IN
Isolated Flyback Converter
with 65V/3.6A Switch
FEATURES
DESCRIPTION
The LT®8302/LT8302-3 is a monolithic micropower iso-
lated flyback converter. By sampling the isolated output
voltage directly from the primary-side flyback waveform,
the part requires no third winding or opto-isolator for
regulation. The output voltage is programmed with two
external resistors and a third optional temperature com-
pensation resistor. Boundary mode operation provides a
small magnetic solution with excellent load regulation.
Low ripple Burst Mode operation maintains high efficiency
at light load while minimizing the output voltage ripple. A
3.6A, 65V DMOS power switch is integrated along with all
the high voltage circuitry and control logic into a thermally
enhanced 8-lead SO package.
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3V to 42V Input Voltage Range
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3.6A, 65V Internal DMOS Power Switch
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Low Quiescent Current:
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106µA in Sleep Mode
380µA in Active Mode
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Quasi-Resonant Boundary Mode Operation at
Heavy Load
Low Ripple Burst Mode® Operation at Light Load
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Minimum Load < 0.5% (Typ) of Full Output
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No Transformer Third Winding or Opto-Isolator
Required for Output Voltage Regulation
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Accurate EN/UVLO Threshold and Hysteresis
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Internal Compensation and Soft-Start
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Temperature Compensation for Output Diode
The LT8302/LT8302-3 operates from an input voltage
range of 3V to 42V and delivers up to 18W of isolated
output power. The high level of integration and the use of
boundary and low ripple burst modes result in a simple to
use, low component count, and high efficiency application
solution for isolated power delivery.
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Output Short-Circuit Protection
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Thermally Enhanced 8-Lead SO Package
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AEC-Q100 Qualified for Automotive Applications
APPLICATIONS
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All registered trademarks and trademarks are the property of their respective owners. Protected
by U.S. patents, including 5438499, 7463497, 7471522.
Isolated Automotive, Industrial, Medical
Power Supplies
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Isolated Auxiliary/Housekeeping Power Supplies
TYPICAL APPLICATION
3V to 32VIN/5VOUT Isolated Flyback Converter
Efficiency vs Load Current
ꢒꢋ
+
V
V
IN
OUT
3V TO 32V
3:1
5V
470pF
9µH
ꢐꢑ
•
220µF
1µH
39Ω
V
IN
•
ꢐꢋ
10µF
–
V
EN/UVLO
SW
OUT
LT8302/LT8302-3
154k
ꢗꢑ
GND
INTV
R
FB
10mA TO 1.1A (V = 5V)
IN
10mA TO 2.0A (V = 12V)
IN
R
REF
ꢗꢋ
ꢘꢑ
ꢘꢋ
CC
10mA TO 2.9A (V = 24V)
IN
1µF
115k
10k
ꢙ
ꢙ
ꢙ
ꢚ ꢑꢙ
ꢚ ꢓꢔꢙ
ꢚ ꢔꢛꢙ
ꢍꢇ
ꢍꢇ
ꢍꢇ
TC
8302 TA01a
ꢔ.ꢋ
ꢀꢁꢂꢃ ꢄꢅRRꢆꢇꢈ ꢉꢂꢊ
ꢕ.ꢋ
ꢋ
ꢋ.ꢑ
ꢓ.ꢋ
ꢓ.ꢑ
ꢔ.ꢑ
ꢐꢕꢋꢔ ꢈꢂꢋꢓꢖ
Rev. G
1
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