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Table 1 provides the recommended derating values for the LED optoelectronic components discussed in this section. For definitions of Quality System (QS) and environments (protected, normal, and severe), see Foundation - Environmental Categories and the derating tables for discrete semiconductors.

Table 1. Derating of LED components

Note: For red, yellow, and green type LEDs, derate power linearly from +25ºC at 1.4mW/ºC. For red, yellow and green LEDs with internal current regulation requiring no external resistors for operation on any voltage from 3V dc to 30V dc, derate power at 3.0mW/ºC above +25ºC.

Laser Diodes

Laser diode derating considerations are the same as those of other diodes covered in the sections on Discrete Semiconductors.

Optical Fiber, Cable and Connectors

Optical fiber, cable and connector derating is not applicable.

Phototransistors, Photodiodes, and Optocouplers

Recommended phototransistors, photodiodes, and optocoupler derating values are summarized in Table 2. More specific guidance on recommendations and manufacturer’s specifications are provided in MIL-PRF-19500/548 and /486 (optocouplers).

Table 2. Recommended Derating Values for Detectors and Optocouplers

Notes:

1. For optocouplers, use manufacturer’s recommended operating conditions to achieve optimum coupling efficiency.

2. Junction temperature should be limited to +95ºC or to 25ºC below the manufacturer’s maximum rating, whichever is lower.

3. Derate power for optocouplers at 2.5mW/ºC above +25ºC.

Infrared Light-Emitting Diodes

Infrared light-emitting diodes should be current de-rated at 50% to +65ºC and above +65ºC, de-rated linearly to +125ºC at 0.67milliamps/ºC.