2 Replies Latest reply on Sep 13, 2011 10:37 AM by user_7880656

    Analog Mux vs Analog Hardware Mux

    wayne.holloway

       

         

      The ADC_DelSig_v2_10.pdf datasheet states "To switch input between samples when using modes other than Continuous, use the Analog Hardware Mux".  Other than switching speed, is there a reason that the Analog Mux component should not be used?  I want to access internal signals using the Analog Mux instead of only the GPIO signals supported by the Analog Hardware Mux.  I want to calibrate the buffered A/D by muxing the1.024V reference and analog which is only supported using the Analog Mux component.  Is there a reason not to do this as long as the A/D is stopped before switching the input and restarted after switching the input?

        • 1. Re: Analog Mux vs Analog Hardware Mux
          wayne.holloway

          I received the following response from Cypress Technical Support:

             

           

             

          Yes, the reason we suggest HW Analog mux is switching speed and hardware control.

             

          Yes, you can use Analog Mux. It is equally good as Hardware Mux if you are stopping ADC conversion before switching and restarting after switching.

          • 2. Re: Analog Mux vs Analog Hardware Mux
            user_7880656

            Just remember to account for settling time.

               

            I see a lot of customers trying to do back-to-back conversions without allowing for some settling time after switching inputs.

               

            This is particularly important if you use hardware SOC (Start of Conversion), as you first sample after

               

            switching inputs may be noisy...

               

             

               

            regards,

               

            Tom Moxon