Part Number: TPS54360
Other Parts Discussed in Thread: LM5576, , LM5005
Hey there,
unfortunately, my circuit with the TPS54360 keeps dying.
Following setup: I have a battery with voltage between 46 to 58V as souce and I need 7V and 24V for my application. The webbench suggensted the TPS54360, which looks pretty good to me. We designed a test board for the application that keeps dying. More specifically, the TPS54360 dies, the rest of the circuit is fine. At first I thought it was getting too hot, but the case temperature was at about 70°C, measured with a thermal imaging camera. Additionally, the over-temperature-protection should prevent that case.
At second thought, its probably the transient voltage that kills the chip. I looked Vin during operation, but the maximum voltage spike i could find was about 0.5V. During the test the circuit was powered through a power supply and not the battery. I could measure a voltage spike at Vin of around max 2V when turning various things like the soldering station on/off. (Propagation over the power grid through the power supply). I doubt that that this was the cause of the failure, because nobody was in the room when the damage happended.
The left over thing is the voltage at SW, which has a transient spike when switching. To my surprise, it has a absolute maximum rating of only 65V, even the 10ns transient is not higher. I measured a transient spike of 72.8V, which explains the failure of the chip.
So my question is: is the TPS54360 suitable for my application? A bad layout could also cause the troubles, so I attached mine below. I tired to minimize the di/dt loop as suggested with the layout in the data sheet. All Components were chosen with the limits from the webbench. If you think that the other components are the problem, i provide the Part numbers/ parameters of those.
Thank you so much for you help!
