Phototransistors amplify the current generated by the light striking the active area. Compared to photodiodes, a large output current can be obtained, even from a small active area.
Gideon Analytical Labs received one failed photocoupler, an Avago HCPL 0630 in an 8 pin DIP SOIC -8 package. The reported failure came from the field after approximately 1.5 years of operation.
The HCPL-0630 optocoupler is an optically coupled logic gate that combines a GaAsP light emitting diode and an integrated high gain photo detector. An enable input allows the detector to be strobed. The output of the detector IC is an open collector Schottky-clamped transistor.
Gideon Analytical Labs received one failed photocoupler, a Vishay IL 420, for failure analysis along with two virgins (unused) optocouplers for comparison.
The basic function of a Photo Coupler is to have electronic isolation, including potential isolation (as in the case of the transformer) in an electrical circuit. Devices of the Photo Coupler family include Photo Transistor, Photo Darlington Transistor, Photo Triac and OPIC. These devices have the characteristics of excellent isolation, high CTR, compact package, high-speed operation, low decay and unit control function not being influenced by field effects.
Gideon Analytical Laboratories received a failed SFH 320 optocoupler in a dual S0-8 package for failure analysis. Optocouplers can be used in many applications, including phototransistor, phototriac, or photodarlington outputs, in a range of through-hole and surface-mount package types. Many are digital optocouplers are used in the automotive industry. They come in a variety of AC and DC configurations, have high noise immunity, and are high temp devices. Two functionally good optocouplers were supplied for comparison.
Gideon Analytical Laboratories received two failed photocouplers for failure analysis. These photocouplers feature a high isolation voltage, high-speed switching, and high collector to emitter voltage. They are used in many types of applications, including power supply, telephones, and fax machines. The optocoupler was electrically tested; there was a short on both input diodes. The goal was to determine the cause of this failure.
After curve trace tests were performed, both failed devices were immersed in a low surface tension dye penetrant This is a modified Mil-Std 1014.
