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ADV7343 DAC1 hot plug issue

ADV7343 DAC1 out when connected with TV heats up the chip  & it ultimately dies off.

Nominal system power consumption is 5V@0.5A. But when this event occurs, the system power consumption shoots upto 5V@1.5A.

This event is frequent but won't occur all the time.

Case 1: When both system & the TV are turned on. And then the video out of ADV is hot plugged with TV.

In this case, half of the time, the chip functions properly. While other half it fails.

Case 2: TV on, system off. Video out is already connected with TV. Now the system is turned on.

In this case most of the times the chip fails.

P.S: No buffer/filters are used except a LPF as shown in schematics.

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  • This sounds like a grounding issue causing latch-up or some other current path being enabled.

    In both case above try grounding the system and TV together first before hot plugging in the video.  This is for debug to try and figure what's happening.

    During the failed condition is video present?  What's the voltage on the DAC output lines.

  • During failed condition, video is not present. Its difficult to measure voltage of video lines in failed condition as the event is

    catastrophic enough to damage entire system.

    Earlier R86 75E was DNP & FB2 was connecting analog & digital grounds together. In this case failure rate was high.

    When R86 75E was populated & FB2 connecting analog & digital grounds was shorted, we havn't seen any failure in latter case. Tried 100 times not even once.

    Now there are 2 variables that are either working in conjunction or alone that has solved the issue. Could you please help analyze the fix?

    Thanks.

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  • During failed condition, video is not present. Its difficult to measure voltage of video lines in failed condition as the event is

    catastrophic enough to damage entire system.

    Earlier R86 75E was DNP & FB2 was connecting analog & digital grounds together. In this case failure rate was high.

    When R86 75E was populated & FB2 connecting analog & digital grounds was shorted, we havn't seen any failure in latter case. Tried 100 times not even once.

    Now there are 2 variables that are either working in conjunction or alone that has solved the issue. Could you please help analyze the fix?

    Thanks.

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