Optocoupler Driver prevents overshoot in power supplies.
September 23, 2004 -
Housed in SOT-23 package, LT4430 incorporates error amplifier with 9 MHz bandwidth that minimizes phase shift, while ground referenced optocoupler drive eliminates secondary feedback path. Product has 3-20 V input supply range and inverting optocoupler driver that supplies up to 10 mA. Overshoot control circuit provides independent control of startup and short-circuit recovery characteristics without compromising loop bandwidth.
(Archive News Story - Products mentioned in this Archive News Story may or may not be available from the manufacturer.)
Original Press release
Linear Technology Corp.
1630 McCarthy Blvd.
Milpitas, CA, 95035
USA
SOT-23 Optocoupler Driver for Isolated Power Supplies Improves Transient Response, Prevents Overshoot
MILPITAS, CA - September 15, 2004 - Linear Technology Corporation introduces the LT4430, an optocoupler driver for isolated power supplies that require tight regulation, fast transient response and overshoot protection. Housed in a tiny SOT-23 package, the LT4430 includes a precision low voltage reference (0.6V, ±0.75%), a high-bandwidth (9MHz) error amplifier, an inverting optocoupler driver and an overshoot control circuit. The LT4430 simplifies loop frequency compensation as the error amplifier's high bandwidth minimizes phase shift and ground referenced optocoupler drive eliminates the secondary feedback path present with existing optocoupler drivers. The LT4430 has a wide input supply range from 3V to 20V. The optocoupler driver supplies up to 10mA and is short-circuit protected. The LT4430 has applications in 48V input isolated DC/DC converters, industrial control systems, automotive and heavy equipment power supplies.
The LT4430's unique overshoot control circuit provides independent control of startup and short-circuit recovery characteristics without compromising loop bandwidth and resultant transient response. Existing optocoupler drivers often require sub-optimum small-signal frequency compensation to control both large-signal dynamic and output overshoot at startup, degrading the power supply's overall performance. Finally, the LT4430's reference stability and error amplifier's 80dB open loop DC gain ensure tight DC regulation over all input line and output load conditions.
The LT4430 is offered in a 6-pin SOT-23 and is rated for operation from -40°C to 85°C. 1,000-piece price starts at $1.75.
Summary of Features: LT4430
600mV, 0.75% Accurate Reference
Wide Input Supply Range from 3V to 20V
Overshoot Control Function Prevents Output Overshoot on Startup and Short-Circuit Recovery
High Bandwidth Error Amplifier Permits Simple Loop Frequency Compensation
Small ThinSOT(TM) Package
Company Background
Linear Technology Corporation was founded in 1981 as a manufacturer of high performance linear integrated circuits. Linear Technology products include high performance amplifiers, comparators, voltage references, monolithic filters, linear regulators, DC-DC converters, battery chargers, data converters, communications interface circuits, RF signal conditioning circuits, and many other analog functions. Applications for Linear Technology's high performance circuits include telecommunications, cellular telephones, networking products such as optical switches, notebook and desktop computers, computer peripherals, video/multimedia, industrial instrumentation, security monitoring devices, high-end consumer products such as digital cameras and MP3 players, complex medical devices, automotive electronics, factory automation, process control, and military and space systems.
Note: LT and LTC are registered trademarks and ThinSOT is a trademark of Linear Technology Corp.
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