ADS7955-Q1: Change channel error

Stefan Seidl

Part Number: ADS7955-Q1

The MUXADC transfers the correct values for channels 0 to 6 after a reset. The reset signal (0x1840 & 0x4200) is sent by the CPLD (orange marking in the oscilloscope capture). However, channel 6 then gets stuck and is continuously transmitted (red marking in the oscilloscope capture), even though the command 0x2840 requests the channels to be switched. Is this error pattern known, and what could be the cause?

7 months ago

0 Joel Meraz 7 months ago

TI__Mastermind 20960 points

Hi Stefan,

I have not seen this issue myself, where a channel gets stuck in auto-1 mode. Expected operation would be to select channel 7 afterwards.

Does this seem to happen with only one device, or with multiple devices?

Regards,
Joel

0 Stefan Seidl 6 months ago

Prodigy 10 points

Hi Joel,

So far, we have only encountered this error in one part, and it only occurs sporadically. Do you have any suggestions as to what we could do? Any suggestions for analyses? Thank you very much for your support.

Best regards,
Stefan

0 Joel Meraz 6 months ago in reply to Stefan Seidl

TI__Mastermind 20960 points

Hi Stefan,

About how often does this issue occur? Are there any conditions that might increase the probability of this happening?

Provided this is a new issue, we might want to have the device returned for failure analysis and deeper investigation.

Regards,
Joel

0 Stefan Seidl 5 months ago in reply to Joel Meraz

Prodigy 10 points

Hi Joel,

We have carried out further analyses and, during desoldering, we found that the fault no longer exists. We assume that this is the result of a self-healing process caused by the heat input during desoldering. Is this phenomenon known, and can we send the component to TI for analysis despite the fact that the fault no longer exists?

Regards,

Stefan

0 Joel Meraz 5 months ago in reply to Stefan Seidl

TI__Mastermind 20960 points

Hi Stefan,

We have not observed a failure similar to this resolve by soldering/desoldering, but there are other issues with other devices that have shown to disappear in this way. Yes, it would still be useful to get this unit back and deprocess it in order to gather any insight into a potential root cause.

Please follow the link below for further information on the return process.

https://www.ti.com/support-quality/additional-information/customer-returns.html

Regards,
Joel

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ADS7955-Q1: Change channel error