A Method to Separate Proton Damage in LED and Phototransistor of Optocouplers

This paper reports proton damage in light-emitting diode (LED) and phototransistor of the Micropac 66296 optocoupler. Our results show that the optocoupler current transfer ratio (CTR) data are influenced by the gain of the phototransistor. Analysis of the test data reveals interesting information, such as the dependence of the phototransistor gain on irradiation and photocurrent. Only a small reduction of phototransistor gain is observed with increasing irradiation when the irradiation is sufficiently large. The phototransistor gain reduction is more significant when comparisons are made with the unirradiated case. Statistical analysis is performed, using a one-sided tolerance method, on the LED light intensity and the optocoupler CTR data. Mean and statistically derated values of the optocoupler CTR and the LED light intensity data at room temperature are presented.