I'm using ADG5408 8:1 mux which has 28Vdc/Open discrete input. We are using 28Vdc for Vdd of the mux and other condition is as below.
- EN: 3.3V, A0~A1: 3.3V
- Vss: GND and connected to exposed pad
- S1~S8: 28Vdc/Open discrete input
- D: Selected signal out
- Overshoot protection circuit is using for the mux's input.
During using the ADG5408, the mux burned out.
Before burning, the mux consumes more current and radiates much heat.
Pin 3 of burned mux was connected to pin 11 so, the resistance between the pins was about 200ohms.
We think that the abnormal connection between pin 3 and pin 11 generated abnormal current and the current make burning out situation.
We are investigating the cause of the problem but that's too difficult. Please let me know your idea.
Because of security problem, I can't upload schematic. I'm sorry.