The OLF249 consists of an LED that is optically coupled to an N-P-N silicon phototransistor mounted in an 8-pin hermetic surface mount flat-pack package. The leads can be formed to provide compliant solder connections to the mounting substrate.

Electrical parameters are similar to the JEDEC registered 4N49 optocoupler, but with much better current transfer ratio (CTR) degradation characteristics due to radiation exposure. Special electrical parametric selections are available on request.