LT8315
560V Micropower No-Opto
IN
Isolated Flyback Converter
with 630V/300mA Switch
FEATURES DESCRIPTION
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Wide Input Voltage Range: 18V to 560V The LT 8315 is a high voltage flyback converter with inte-
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630V/300mA Integrated Power Switch grated 630V/300mA switch. No opto-isolator is needed for
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No Opto-Isolator Required for Regulation regulation. The device samples the output voltage from the
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Quasi-Resonant Boundary Mode Operation isolated flyback waveform appearing across a third wind-
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Constant-Current and Constant-Voltage Regulation ing on the transformer. Quasi-resonant boundary mode
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Low Ripple Light Load Burst Mode Operation operation improves load regulation, reduces transformer
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Low Quiescent Current: 70A size and maintains high efficiency.
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Programmable Current Limit and Soft-Start
At start-up, the LT8315 charges its INTV capacitor via a
CC
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TSSOP Package with High Voltage Spacing
current source attached to the DRAIN pin. During normal
operation, the current source turns off and the device
draws its power from a third winding on the transformer.
APPLICATIONS
The LT8315 operates from a wide range of input supply
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Isolated Telecom, Automotive, Industrial, Medical
voltages and can deliver up to 15W of power. It is available
Power Supplies
in a thermally enhanced 20-pin TSSOP package with four
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Isolated Off Line Housekeeping Power Supplies
pins removed for high voltage spacing.
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Electric Vehicles and Battery Stacks
All registered trademarks and trademarks are the property of their respective owners.
TYPICAL APPLICATION
20V to 450V Isolated 12V Supply Efficiency
IN IN OUT
V 90
IN
20V TO 450V
0.44F
80
5:1:2
600
20k
+
V
70
640H OUT
12V
93.1k
47pF
60
200F
160H
10F
BIAS DCM
V = 50V
IN
50
EN/UVLO FB
V = 100V
V
OUT IN
4mH
V = 150V
61.9k 5.11k IN
INTV 5mA to 220mA (V = 50V) V = 250V
CC IN
40 IN
TC 5mA to 320mA (V = 100V) V = 350V
IN
LT8315 IN
10F
5mA to 380mA (V = 150V) V = 450V
IN
IN
SMODE DRAIN
5mA to 440mA (V > 250V) 30
IN
0 100 200 300 400 500
LOAD CURRENT (mA)
V SOURCE
C
8315 TA01b
100k
IREG/SS GND
330m
470pF
22nF
121k
8315 TA01a
8315fa
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For more information www.linear.com/LT8315
EFFICIENCY (%)LT8315
ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION
(Note 1)
TOP VIEW
DRAIN .....................................................................630V
DRAIN 1 20 GND
BIAS, EN/UVLO .........................................................40V
DRAIN 2 19 NC
INTV ......................................................................15V
CC
DRAIN 3 18 SOURCE
SMODE ............................................................... INTV 17 EN/UVLO
CC
21
16 SMODE
SOURCE, TC, FB, V , IREG/SS ....................................4V
C GND
15 GND
DCM ...................................................................100mA
14 IREG/SS
INTV 8 13 V
CC C
Operating Junction Temperature (Note 2)
BIAS 9 12 FB
LT8315E, LT8315I .............................. 40C to 125C
DCM 10 11 TC
LT8315H ............................................ 40C to 150C
FE PACKAGE
Storage Temperature Range .................. 65C to 150C
20(16)-LEAD PLASTIC TSSOP
= 38C/W, = 10C/W
Lead Temperature (Soldering, 10 sec) .................. 300 C JA JC
EXPOSED PAD (PIN 21) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION