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LT4430_1 Datasheet, PDF (1/26 Pages) Linear Technology – Secondary-Side Opto-Coupler Driver Ground-Referenced Opto-Coupler Drive | |||
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LT4430
Secondary-Side
Opto-Coupler Driver
FEATURES
n 600mV Reference (1.25% Over Temperature)
n Wide Input Supply Range: 3V to 20V
n Overshoot Control Function Prevents Output
Overshoot on Start-Up and Short-Circuit Recovery
n High Bandwidth Error Ampliï¬er Permits Simple Loop
Frequency Compensation
n Ground-Referenced Opto-Coupler Drive
n 10mA Opto-Coupler Drive with Current Limiting
n Low Proï¬le (1mm) ThinSOTTM Package
APPLICATIONS
n 48V Input Isolated DC/DC Converters
n Isolated Telecommunication Power Systems
n Distributed Power Step-Down Converters
n Ofï¬ine Isolated Power Supplies
n Industrial Control Systems
n Automotive and Heavy Equipment
DESCRIPTION
The LT®4430 drives the opto-coupler that crosses the gal-
vanic barrier in an isolated power supply. The IC contains
a precision-trimmed reference, a high bandwidth error
ampliï¬er, an inverting gain of 6 stage to drive the opto-
coupler and unique overshoot control circuitry.
The LT4430âs 600mV reference provides ±0.75% initial
accuracy and ±1.25% tolerance over temperature. A high
bandwidth 9MHz error ampliï¬er permits simple frequency
compensation and negligible phase shift at typical loop
crossover frequencies. The opto-coupler driver provides
10mA of output current and is short-circuit protected.
A unique overshoot control function prevents output
overshoot on start-up and short-circuit recovery with a
single capacitor.
The LT4430 is available in the low proï¬le 6-lead TSOT-23
package.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. ThinSOT is a trademark of Linear Technology Corporation. All other
trademarks are the property of their respective owners.
TYPICAL APPLICATION
Simpliï¬ed Isolated Synchronous Forward Converter
VIN
+
ISOLATION
BARRIER
â¢â¢
VOUT
+
Isolated Flyback Telecom Converter
Start-Up with Overshoot Control
(See Schematic on Back Page)
LT1952
â¢
â¢
FG CG
SYNC
VCC
LTC3900
VCC
VIN
OPTO
LT4430
GND
COMP
OC
FB
4430 TA01
VIN
50V/DIV
VOUT
5V/DIV
OVERSHOOT CONTROL
IMPLEMENTED
t = 5ms/DIV
4430 TA01b
4430fb
1
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