SN74CBTD3384: channel failure

Joyce Gao

Part Number: SN74CBTD3384
Other Parts Discussed in Thread: ADC121S101,

Hi expert,

Customer connects 1 CH (pin10) of SN74CBTD3384 with 3 nCS pins of 3pcs of ADC(ADC121S101) together. Sometimes this channel fails (pin10 shorten to pin20, that is shorten to GND). The issue hasn't shown obvious repentance but only this pin has such failure problem. What's the possible reason? Could is be over-current due to connected to 3 loads? Plus, what's the major failure reason of such switches? We could now think of ESD, over-current.

Many thanks!

Joyce

over 2 years ago

0 Joyce Gao over 2 years ago

TI__Intellectual 2870 points

Plus, is there an ESD diode inside the device between each input pin & VCC? I found this doc Eliminate Power Sequencing with Powered-off Protection Signal Switches (Rev. C)

0 Clemens Ladisch over 2 years ago

Guru 316920 points

The channel current limit is 128 mA; it is unlikely that it was exceeded. (Or is there more than one device that couly by trying to drive this line?)

I'd guess that this is because of overvoltage, i.e., ESD. Is this on one board, or are the connectors/cables or anything else that can be touched?

0 Rami Mooti1 over 2 years ago in reply to Joyce Gao

TI__Mastermind 35528 points

Hey Joyce,
Is it possible to get any waveforms or measurements on the line?
Additionally, there is no ESD cell from input pins to VCC on the mux.

Thanks,
Rami

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SN74CBTD3384: channel failure