Isolated voltage ADuM5028-3BRIZ :: ADC converter

Hello,

I'm searching for a solution which could provide isolated 3V3 voltage to supply the ADC converter. It looks that ADuM5028-3BRIZ would be a very good choice, but I'm not completly sure if it will be the best choice for my application, because of noise provided by ADuM5028-3BRIZ.
What do you think - Is ADuM5028-3BRIZ suitable device (with included suggested filter at input and output) to supply a noise sensitive devices (like an ADC converter) directly?
Another option is to use the ADuM5028-5BRIZ and then a LDO (for example 3V3 version of ADP7142 IC) to provide a sutable voltage (and more stable voltage) needed to supply the ADC converter? What do you think?

Many thanks,
Kind regards,
Dejan.

  • Hi Dejan,

    It would depend on your ADC's noise sensitivity. If the ADuM5028's noise spec (Vpp) is sufficient then that would do.

    Else, the ADP7142 would be a great alternate since it is designed for your particular application with 11uVrms of noise.

    Regards,

    Bryan

  • Hello Bryan,

    I'm exactly planning to use a current/voltage/power monitor (INA238) made by TI. In a datasheet is written that PSRR of this monitor is +-0.1uV/V (-140 dB) typical and +-1uV/V maximal (-120 dB).
    Expected noise of ADUM5028-3BRIZ is 130 mVpp (+-65mVp). If my calculation is correct, this leads to 6.5 nV (at 0.1uV/V PSRR) or 65 nV (at 1uV/V PSRR) change in offset voltage. Did I forget something or seems my calculation looks right?

    Many thanks,
    Dejan.