Hi
We have seen some failed tps65105 parts from the field and we are trying to determine the cause of the problem and have run a few lab tests to try to create the problem. Below is a schematic of the interface.
We have been able to destroy some parts by lowering the input voltage and have seen a working part fail with an input voltage of 3.7V and below.
The symptom is current flow on the input of > 1.5A when no LCD interface is even connected. (Typically the current is about .45A)
When we measure the resistance of the 5V rail we are seeing a very low resistance (< 10ohms and sometime about 1.5 ohms) without the TI part being powered up
We have verified that the part does get destroyed by removing the part on a failed board and replacing the part with a new part and then the board works as usual.
In reviewing the datasheet I did not see specific mention that this should be avoided and it appeared the part limits its output current so I was thinking the part was protected against large input currents being generated.
We did not specifically design the board but it was designed for us for our product and I am trying to do some advanced debugging
i have some failed parts. Perhaps TI could examine these parts
Do you have any specific recommendations for me to test out
