Optocoupler driver powers up isolated supplies

The LT4430 is an optocoupler driver for isolated power supplies that require tight regulation, fast transient response and overshoot protection.

Linear Technology has introduced 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 minimises 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 3 to 20V.

The optocoupler driver supplies up to 10mA and is short-circuit protected.

The LT4430 has applications in 48V input isolated DC/DC convertors, 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 suboptimum 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 to +85C.

1000-piece pricing starts at $1.75.

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