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I have been surveying transmission buffers for digital transfer from an ADC to an FGPA.

The 74xxxx series looks like a good choice to me.

I noticed that some manufacturers provide isolation buffers.

The datasheets say the major use is for automotive/industrial.

Is it because automotive/industrial applications have high voltage on another board, which could generate high voltage and damage the motherboard?

I've read other applications that emphasize noise reduction when using isolation buffers.

Is that so?

JRE
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curlywei
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1 Answers1

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When to use isolation buffer(Digital)?

  1. When the connections across the proposed barrier should not be galvanically connected (safety reasons such as some power supplies)
  2. When you want to prevent ground loop currents i.e. breaking the 0 volts is usually the best policy
  3. When there is a large voltage difference between 0 volts on one side and 0 volts on another.
Andy aka
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  • Hey Andy, for #3, how would you go about knowing the ground difference between the 0V potentials? Would you measure it with a DVM? For example, it seems that if I were to interface two different PCBs through a serial bus (e.g. i2c), I would have to always, somehow, quantify the difference between the two circuit grounds? – Big6 Nov 23 '22 at 21:40
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    You'd either know it beforehand or measure it and research how big in magnitude it could become in certain situations @Big6 – Andy aka Nov 23 '22 at 22:06
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    @Big6 - The problem is that you may not know ahead of time how much of a ground (or voltage) difference there may be. This is particularly true in a industrial environment, where you have equipment, especially those with large motors in them, using large amounts of power turning on and off. – SteveSh Nov 24 '22 at 00:43