7 Replies Latest reply on Mar 18, 2018 7:05 PM by user_342122993

    Interfacing iso. ADC like AD74XX

    MartinWattenberg

      Hi everyone,

       

      I need to interface two isolated ADCs like the AD7403 from Analog Devices to the PSoC 5LP.

      The ADC puts out a data stream of 1 and 0 and the average of this stream represents the analog value.

      Of course a simple RC filter could be used to generate a moving average which could be samples by PSoC's ADC, but I was wondering if there is a more elegant solution to this.

       

      At the moment I am running a single AD7403 at 5 MHz (the lowest possible frequency).

      The digital output of the ADC is acquired by a status register.

      A DMA then transfers the data to the digital filter block where I use a SINC4 low pass filter.

      This way I am creating single byte transfer requests at 5 MHz on the DMA.

      So far it seems to be working fine but I have not checked the integrety of the data.

       

      Can the DMA really handle such a frequency?

      I need to interface two of those ADCs and possibly at higher frequencies (10 MHz each) - do you think my solution is viable for such an application?

      Is there an alternative?

       

      I attached a small example in PSoC Creator and the datasheet of the AD7403

       

      Thank you