LT8302_15 Datasheet, PDF (1/26 Pages) Linear Technology – 42VIN Micropower No-Opto Isolated Flyback Converter with 65V/3.6A Switch

Features
n _{2.8V to 42V Input Voltage Range}
n _{3.6A, 65V Internal DMOS Power Switch}
n _{Low Quiescent Current:}
106µA in Sleep Mode
380µA in Active Mode
n _{Quasi-Resonant Boundary Mode Operation at}
Heavy Load
n _{Low Ripple Burst Mode}^® _{Operation at Light Load}
n _{Minimum Load < 0.5% (Typ) of Full Output}
n _{No Transformer Third Winding or Opto-Isolator}
Required for Output Voltage Regulation
n _{Accurate EN/UVLO Threshold and Hysteresis}
n _{Internal Compensation and Soft-Start}
n _{Temperature Compensation for Output Diode}
n _{Output Short-Circuit Protection}
n _{Thermally Enhanced 8-Lead SO Package}
Applications
n _{Isolated Automotive, Industrial, Medical Power}
Supplies
n _{Isolated Auxiliary/Housekeeping Power Supplies}
LT8302
42V_IN Micropower No-Opto
Isolated Flyback Converter
with 65V/3.6A Switch
Description
The LT^®8302 is a monolithic micropower isolated 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 compensation resistor. Bound-
ary 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.
The LT8302 operates from an input voltage range of 2.8V
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.
L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks
of Linear Technology Corporation. All other trademarks are the property of their respective
owners. Protected by U.S. Patents, including 5438499, 7463497, 7471522.
Typical Application
2.8V to 32V_IN/5V_OUT Isolated Flyback Converter
V_IN
2.8V TO 32V
10µF
V_IN
EN/UVLO SW
LT8302
GND
R_FB
INTV_CC
1µF
R_REF
TC
3:1
470pF
•
9µH
1µH
39Ω
•
V_OUT+
5V
220µF
V_OUT–
154k
115k 10k
10mA TO 1.1A (V_IN = 5V)
10mA TO 2.0A (V_IN = 12V)
10mA TO 2.9A (V_IN = 24V)
8302 TA01a
For more information www.linear.com/LT8302
Efficiency vs Load Current
90
FRONT PAGE APPLICATION
85
80
75
70
65
V_IN = 5V
V_IN = 12V
V_IN = 24V
60
0 0.5 1.0 1.5 2.0 2.5 3.0
LOAD CURRENT (A)
8302 TA01b
8302fa
1