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selection of DAC8760 output using analog switch.

Dexter
Intellectual 450 points
Other Parts Discussed in Thread: DAC8760

hello,

In my application, i am considering to use two DAC8760 for current and voltage output. Voltage outputs are muxed through analog switch.  and similarly current outputs are muxed through analog switch.

Is it a right approach?? 

Is it possible to drive the load from DAC8760 through analog mux??

will i get proper short circuit protection and open circuit detection in this case.

  • 0
    TI__Genius 10615 points

    Hi Gaurav,

    Do you have any part numbers that you are planning on using?

    Are you planning on sharing the two current output and sharing the two voltage outputs?

    Or using a mux per DAC8760?

    Can you share some more details on this application?

    If you are trying to have a single output that you can switch between current and output, we have a good document that goes over a solution for this. Combined Voltage and Current Output. If you have any questions about the document please let us know.

  • 0 in reply to Eugenio Mejia
    Intellectual 450 points

    hello,

    thanks for prompt response.

    I am  planning on sharing two current outputs and sharing two voltage output through analog switch..

    I have not finalized the analog switch component yet...  right now studying for feasibility of sharing for output stage...

    Any suggestion??

  • 0 in reply to Dexter
    Intellectual 450 points

    hello ,

    Do you have any suggestion for my last question ??

  • 0 in reply to Dexter
    TI__Mastermind 46290 points
    Gaurav,

    As Eugenio eluded to in his post, most often the requests we see regarding sharing outputs are to share a voltage and current output on a single terminal to create a so called "Universal Analog Output" module. This is often perceived as beneficial because it adds flexibility for a design to switch the pin from voltage to current via software. Historically, this was implemented by building a single module slightly different for voltage or current outputs in the factory or by a technician installing a jumper in the field.

    Occasionally I do see requests to implement redundancy along the lines of what you described where two voltage and two current outputs are connected together. In the event that one of the channels is damaged the other is there to take over. I'm not sure if this is what you had in mind or not based on what you have posted so far.

    So - in short, either MUX scheme is reasonable, it just depends on what you are trying to achieve by doing so. Could you explain what your goal is in this design?
  • 0 in reply to Kevin Duke
    Intellectual 450 points
    In my application, i want to provide voltage and current output in normal mode (voltage and current outputs are provided from different output pins , they are not shorted) . But in case of a failure of board controller or DAC failure , i want to provide a pre-configured voltage/current output.

    I planning to do this by using two DAC8760. first DAC will periodically provide output through contoller....the other DAC will latch a preconfigured output during power on ..On fault detection of controller/DAC , i am trying to provide this output through analog switch selection...

    so my question is,, can i drive voltage/current output from DAC8760 through Analog MUX/Switch.

    Regards
    Gaurav
  • 0 in reply to Dexter
    TI__Genius 10615 points
    You can use the DAC8760 through an Anlog MUX/switch. Do keep in mind that of the effects that the the on-resistance of the MUX will introduce. Namely, in voltage mode it will add a voltage drop proportional to the size of the resistance. And while in current mode, the size of the series resistance will contribute to the compliance voltage requirement. Therefore picking a switch with a small on-resistance will be very important.

    Out of curiosity, how are you using the /ALARM pin on the DAC8760? Are you reading the fault state and from there deciding whether to feed it forward to the load via this other latched DAC?
  • 0 in reply to Eugenio Mejia
    Intellectual 450 points

    hello,

    thanks for reply...

    controller will read fault state and from there it select output through analog mux