Electricity path: Car battery → entering device main PCB → FFC cable → 3.3V regulator on sub PCB → FPCA cable → This transistor on FPCA cable
However, we never found any problem with this transistor before, this is the first case. So, my supplier is not willing to conduct any countermeasures to prevent this issue.
Has anyone found yourself in this kind of situation and how do you explain to customer for a closure?
This is always a difficult situation. How do you tell your customer that your supplier won’t do a corrective action. I recommend seeing if there is anything you can do to provide the customer some kind of corrective action. You may want to review the industry council whitepaper on EOS which gives a great fishbone diagram for all kinds of EOS root causes. It can be downloaded at Industry Council White Paper 4: Understanding Electrical Overstress | EOS/ESD Association, Inc.. If you find a root cause that seems to fit the situation, like hot plugging, you could see if there are any instructions to the customer you could update, like make sure the cable is de-energized and grounded prior to plugging it in. If there is nothing else you can do without the supplier’s support you could also say this is a first-time occurrence and you will continue to monitor for additional failures. Perhaps the customer will take this answer. If not, you may need to use an independent lab to do the failure analysis. Thanks
I agree with Andy, this is a sticky situation and he has given a good path forward.
Additionally, I would suggest getting with your contracts people and review the statement of work and any quality clauses you may have flowed to your supplier. Typically, there is some sort of statement about suppling defect free components. You may have a contract path you can go down to have your supplier perform the cause analysis .
