by Jack Goho
Gideon Analytical Laboratories received five failed ST Microelectronics BTA16-800 triacs and one good ST Microelectronics BTA16-800 triac for comparison. A triac is a generic trademark for a three terminal electronic component that conducts current in either direction when triggered. Its formal name is bidirectional triode thyristor or bilateral triode thyristor. The goal was to determine the cause of these failures.
Gideon Analytical Laboratories went straight to work conducting failure analysis on the ST Microelectronics BTA16-800 triacs. We will discuss three of the samples. One had an abnormal curve trace between A1 and A2; normally there is no connection unless the triac is turned on. The samples were decapsulated. There were no dicing problems; there was no cracking. In sample 1, the die was separated from the copper and solder on the surface and magnified to investigate why it had an abnormal curve trace. Sample 1 indicated that the junction was gone between A1 and A2, common in transistors where too much voltage has been applied. Sample 2 was shorted across all terminals. First, the sides were inspected for fractures. Next, it was decapsulated. A curve trace of sample 2 showed all terminals shorted. Under magnification, the cause for failure was exposed. The left hand corner showed why the die was shorted; it was buried under the solder and contained by the solder during what appeared like an over voltage or surge current. It did not appear to be a sustained event. The backside of sample 2 showed degradation. Sample 5 also had terminals shorted both before and after decapsulation, induced short at 809V 60A. Common among all of the samples was no evidence of overheating or melting. After a thorough electrical analysis, the conclusion we reached was these ST Microelectronics BTA16-800 triacs were failing because of di/dt that was too high.
Gideon Analytical Laboratories is one of the preeminent electronic failure analysis laboratories in the world. For decades now, we have worked to help companies to solve their problems. This has saved time and money. We can help you too. If you are having problems with any type of capacitors, connectors, gate drivers, oscillators, potentiometers, relays, diodes, transistors, voltage regulators, transformers, or even triacs, we can help you. If it is electrical and is failing, give Gideon Analytical Laboratories a call today.