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How we can make a isolation many ADC signal to signal ic

neeraj sharma
Prodigy 35 points

Dear all,

i need to design a ckt that have many  ADC output but i need to isolate with control card and power card. it is possible to design with single IC. if yeas then please provide me full description and IC part Number.

  • 0
    TI__Mastermind 29635 points
    Hi Neeraj,

    I am not quite sure what you are requesting. However, I think your post may be more appropriately answered by folks in our Data Converters Forum. I'll move the thread over to that forum for you.

    In the meantime, please provide a block diagram or more detailed description about the application that you are designing for.

    Regards,

    Michael
  • 0
    TI__Guru* 92655 points

    Neeraj,


    On top of a better description and a block diagram, it would help to say what you are measuring and some of the specifications that you need.

    In particular, data rate and resolultion (what sort of noise you can tolerate) would be very helpful. We'd also like to know about what other functionality you might need. Maybe you need multiple channels, or some sort of programmable gain amplifier (PGA).

    Any added description will help us with an answer.

     

    Joseph Wu

  • 0 in reply to Joseph Wu
    Prodigy 35 points

    Hi Joseph Wu,

     In our Design We are planing to isolate the all ADC Signal which come through power section in to control section, we need to separate each other so that is any switching noise or any other problem does not effect to control part . That is my problem how we can make many signal isolate to power card and control card. If any other way so please tell me.

  • 0 in reply to neeraj sharma
    TI__Guru* 92655 points
    Neeraj,


    I don't know if there's a good answer to what you're looking for. In general, dealing with the noise of the power supplies and isolating it from the analog section is part of the design and layout of the system. There aren't any parts that I know of that will make these problems just go away. It's not just the voltage ripple that you see from the supplies, there is also EMI that can be seen as noise.

    I do have a couple of things to think about when working on a new system.

    Definitely sub-regulate down from a DC-DC converter with an LDO. The LDO should help clean up any switching noise that might be seen from the analog section. Don't use inductors in the signal path or the power path after the LDO. The ADC still has some switching based on capacitive sampling, and that switching can cause voltage spikes (as L(di/dt))

    Generally, we don't use split ground planes. If you want you can layout the grounds as if there is a separate analog and digital ground plane, but connect the two under the ADC. You'll still have to worry about return currents and how they can affect the ground if returns are different from one section to another.

    Use the ground plane as shielding and try to keep it continuous under the analog section.

    Don't cross digital signals over analog signals. Try to keep the analog section compact so that the lead lengths are as short as possible. This will help reduce the effect of EMI. Input filtering can help reduce as well while acting as an anti-aliasing filter

    I'm not sure if this is what you're asking for. If you have any further questions though, feel free to post back to the forum.


    Joseph Wu