Part Number: ISO7421
I just got a claim from a customer regarding communication problems which is caused by a defect of an ISO7421.
The electronic environment is between -20°C and 25°C (it's truck trailer with built in refrigerator) and is sealed with a protection paint. Ground shifts are at a maximum of 70V.
Is there any known issue with this kind of isolators? Is it possible to send the device in to TI for further analysis?
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Hi Tobias; welcome to the E2E forums! Thank you for the additional context. There aren't immediate known issues to share about this isolator, but please allow me 3-5 days to investigate and follow up with you here. Thank you for your time, Manuel Chavez
In reply to Manuel Chavez:
Thanks for the quick reply.
It's just the forward (B) channel, the other channel (A) works.
There's no signal transmission from IN to OUT anymore, it doens't matter if it's a high or low level at the input.
Both supply lines are switched due to sleep current reduction.
In reply to Tobias Hensle:
There's nothing to apologize ;)
Regarding your questions:
1.) The forward channel stopped operating completely.
2.) The device passed every automotive conform EMC test and passed the EOL test. The problem occured after sveral miles in the field.
3.) What do you mean with input/output monitored? I measured the signal with an oscilloscope.
About the system:
It's a locking system for truck trailes with LIN communication. The device is separated into two sections(on the same PCB) a LIN and a Motor section.
The maximum isolation voltage is 70.The µC Port Pin PC7 is used to switch the supply, the I/O of the ATMega168PA are capable of sourcing upt to 40mA, the ISO7421 needs 5mA max. Both Vcc1 and Vcc2 are switched.
Yes, I replaced the defect part with a new one and the communication between both microcontrollers works perfectly now.
Edit: This failure just happend once until now.
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