MP4864A - switch stability

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1

Hello,

I am working with the MP4864A Analog Board to switch a device.

My goal is to turn on a specific set of channels on the board. When I initially run the program, the correct channels are activated. However, after approximately 5 minutes, the active channels change unexpectedly. For example, channel 4 may switch to channel 7. This happens for all the test runs except the first one. For the first run, the switch holds the states.

The channel shifts appear to be random and do not follow a consistent pattern. In different runs, I have observed shifts of around 2, 3, or even 10 channels.

To retain the channel states, I keep the latch signal high at the end of the program. Despite this, the channel configuration still changes after some time.

Here are some more details about what is being used to control the board:

  1. Raspberry Pi 5
  2. VDD - 12V, VLL -3V
  3. Clock, Data and Enable lines all remain stable after the channel configuration.

Has anyone encountered a similar issue or have any suggestions on what could be causing these unexpected channel shifts? Any insights would be greatly appreciated.

Thank you.

2

Apologies for the delayed response on this request. I have personally never encountered any unexpected switches for this part. I have the following questions:

  • Do you happen to have a schematic that we can look at?
  • Do you perhaps have any pull-up or pull-down resistors to filter out any possible bouncing effects?
  • Have you ruled the possibility of any electromagnetic interference at all?

I know it has been some time since you have posted, so any updates here would be much appreciated. Looking forward to hearing back from you.

Best,
Krishan