Radiation-Tolerant Phototransistor Non-Hermetic Surface-Mount Optocoupler

The OLC449 can be used for large satellite constellation applications that require optical isolation in radiation environments such as gamma, neutron, and proton radiation with a high CTR and low saturation VCE. Each optocoupler consists of an LED and N-P-N silicon phototransistor that is electrically isolated, but optically coupled inside a non-hermetic six-pin Leadless Chip Carrier (LCC) package.

Electrical parameters are similar to the JEDEC registered 4N49 optocoupler, but with a higher CTR and better CTR degradation characteristics due to radiation exposure.

The hermetic surface mount variant of the OLC449 optocoupler is available as the OLS449, both in a non-screened catalog version as well as a high-reliability screened version.

The OLC449 is designed for a low LED operating current while providing excellent radiation tolerance margins.


    • Radiation tolerant version of the 4N49U
    • High current transfer ratio (CTR) is guaranteed:
      • – Over –55 °C to +125 °C ambient temperature range
      • – At LED current of 1mA
    • 1000 VDC electrical isolation
    • Same processing and construction as the OLC249, but with a higher CTR

Images & Diagrams


    • Memo
    • Condition
    • CTR @ IF = 1 mA
    • CTR Min.
    • 1500
    • CTR Max.
    • 4000
    • BVCEO (V)
    • 65
    • Vcc Max. (V)
    • Switching Time (μs)
    • 25
    • Isolation @ VDC 1 Sec.
    • 1000
    • Package Photo
    • Package Info
    • 6-Lead Non Hermetic LCC
    • Radiation Tolerant
    • Yes
    • No Base Connection