LT4430ES6 Datasheet, PDF (1/20 Pages) Linear Technology – Secondary-Side Optocoupler Driver

LT4430
Secondary-Side
Optocoupler Driver
FEATURES
■ _{600mV Reference (1.25% Over Temperature)}
■ _{Wide Input Supply Range: 3V to 20V}
■ _{Overshoot Control Function Prevents Output}
Overshoot on Startup and Short-Circuit Recovery
■ _{High Bandwidth Error Amplifier Permits Simple Loop}
Frequency Compensation
■ _{Ground-Referenced OptoCoupler Drive}
■ _{10mA OptoCoupler Drive with Current Limiting}
■ _{Low Profile (1mm) ThinSOT}^TM _Package
U
APPLICATIO S
■ _{48V Input Isolated DC/DC Converters}
■ _{Isolated Telecommunication Power Systems}
■ _{Distributed Power Step-Down Converters}
■ _{Offline Isolated Power Supplies}
■ _{Industrial Control Systems}
■ _{Automotive and Heavy Equipment}
DESCRIPTIO
The LT^®4430 drives the optocoupler that crosses the
galvanic barrier in an isolated power supply. The IC con-
tains a precision-trimmed reference, a high bandwidth
error amplifier, an inverting gain of 6 stage to drive the
optocoupler and unique overshoot control circuitry.
The LT4430’s 600mV reference provides ±0.75% initial
accuracy and ±1.25% tolerance over temperature. A high
bandwidth 9MHz error amplifier permits simple frequency
compensation and negligible phase shift at typical loop
crossover frequencies. The optocoupler driver provides
10mA of output current and is short-circuit protected.
A unique overshoot control function prevents output
overshoot on startup and short-circuit recovery with a
single capacitor.
The LT4430 is available in the low profile 6-lead SOT-23
package.
, LTC and LT are registered trademarks of Linear Technology Corporation.
ThinSOT is a trademark of Linear Technology Corporation.
TYPICAL APPLICATIO
Simplified Isolated Synchronous Forward Converter
ISOLATION
BARRIER
V_IN
+
••
V_OUT
+
Isolated Flyback Telecom Converter
Startup with Overshoot Control
(See Schematic on Page 20)
LT1952
•
•
FG CG
SYNC
V_CC
LTC3900
V_CC
V_IN
OPTO
LT4430
GND
COMP
OC
FB
4430 TA01
V_IN
50V/DIV
V_OUT
5V/DIV
OVERSHOOT CONTROL
IMPLEMENTED
t = 5ms/DIV
4430 TA01b
4430f
1