ADE7816 Reference Voltage

Here’s an interesting question.  While the ADE7816  has an internal reference voltage, ADI pretty much recommends using an external reference voltage to keep it constant over temperature. 

The dev board uses an ADR208ART reference, but the website says that part is obsolete and should be replaced by the ADR3412.   My question is if I have three ADE7816 parts in the system can I use one ADR3412 for all three 7816’s or do I need three reference supplies?

Thanks

  • 0
    •  Analog Employees 
    on Oct 29, 2014 7:38 PM

    Hi Tim-S,

    I haven't heard of anyone doing this before but It shouldn't be an issue to use one ADR3412 as the reference for three ADE7816's. It is important to note the ripple rejection ratio of the ADR3412 because any instability in the supply for the reference can translate to a instability in the reference voltage with an RRR = -60 dB. To help the stability of all 3 ADE7816's using the same reference, it would also be recommended to clock all 3 off the same clock.

    Let me know if any issues come up.

    Regards,

    Dlath

  • AD, is the original assertion that "ADI pretty much recommends using an external reference voltage" true?

    We're pretty happy with the 7816's internal reference specs of 10 ppm/°C typical and 50 worst case, and we're aware of the need to double that error for energy measurements as specified on p17 of the datasheet.  Are there any other considerations we should be concerned about?

  • 0
    •  Analog Employees 
    on Oct 30, 2014 5:28 PM

    Hi dBC,

    The ADE7816, as stated, has a typical spec of 10 ppm/°C and max spec of 50 ppm/°C. It is only recommended to use an external reference if that spec is not enough for an application. If not enough, then an external reference can be used to improve temperature performance as needed. By no means is it necessary if the temperature coefficient is satisfactory.

    Regards,

    Dlath

  • 0
    •  Analog Employees 
    on Aug 2, 2018 2:48 PM
    This question has been assumed as answered either offline via email or with a multi-part answer. This question has now been closed out. If you have an inquiry related to this topic please post a new question in the applicable product forum.

    Thank you,
    EZ Admin