Inputs coupling caps

Hardware questions and issues with the FV-1

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gfisys
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Inputs coupling caps

Post by gfisys »

Hi Frank, in the reference application schematic on the FV-1 datasheet there are a pair of coupling caps (one for each input), and the accompanying paragraph says "The inputs should be conducted through coupling capacitors, as the inputs are internally biased to a VDD/2 potential."

Now if the source driving the FV-1 inputs is already biased at VDD/2, can we omit coupling caps?
frank
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Post by frank »

You should include the caps, the converters creates this reference internally and is important for proper function. An external Vdd/2 could be slightly off from what the converters want to generate.
Frank Thomson
Experimental Noize
gfisys
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Joined: Wed Dec 14, 2011 7:39 pm
Location: Indonesia
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Post by gfisys »

Noted, thanks.

Still on the topic, can I use the voltage that appears on pin 3 (Mid) as a reference for biasing other parts of the circuits (e.g op-amps)?
frank
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Post by frank »

You shouldn't use that pin, it is really for the converters and shouldn't be loaded.
Frank Thomson
Experimental Noize
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