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I am currently designing a PLC-like module based on a STM32 microcontroller. I want to have up to 8 analog outputs generating 0-10V or 4-20mA signal. I am heavily relying on this design by TI: https://www.ti.com/lit/ug/tidubl9a/tidubl9a.pdf?ts=1713799766888.enter image description here

Here, the output from the DAC is fed to the multiplexer, which splits it into 8 channels - 4 voltage and 4 current channels. The current channels are based on the XTR111 module, which according to the data sheet can be used both as a current and voltage output. enter image description here

My question is: can one XTR111 module be placed between the DAC and multiplexer instead of having one for every channel? It would be a big save, as only one IC would be used instead of 8. What the downsides of this approach?

Do you have any other ideas on how to generate 0-10V and 4-20mA from STM32 DAC?

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  • \$\begingroup\$ How would the current in one circuit continue to flow when you switched? 16 mA on for 25% of the time would be 4 mA. \$\endgroup\$
    – Transistor
    Commented Apr 23 at 19:58
  • \$\begingroup\$ @Transistor I guess I didn't think about that. How would you suggest to do it, could you maybe point me in the right direction? I prefer to do it at low cost, but if using separate XTR111 ICs (or similar) would be the most reliable solution then so be it. \$\endgroup\$
    – Sobekurxo
    Commented Apr 25 at 15:53
  • \$\begingroup\$ I don't have any ideas for now and don't have time to look into it for you. Does the MUX in the TDA-00760 maintain output on each channel while it's switching? If so it must have sample and hold of some sort. \$\endgroup\$
    – Transistor
    Commented Apr 25 at 16:32

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