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why use buffer voltage follower?

dl09

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betwixt

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The honest answer is you probably don't need one but the reason they are used is to provide isolation between the source of the signal and the load placed upon it. The buffer would have a high input impedance so it doesn't load the source and a low output impedance so it can provide more power to the load. For example, and it depends on the oscillator you are using, it may shift frequency if you place components on the output pin or the output voltage may drop as you draw current from it. The prevent that happening, you use a voltage follower, it doesn't amplify the voltage, you get the same out as you put in, but it prevents changes at it's output from influencing the source feeding it.

Brian.
 

andre_teprom

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why use a buffer voltage follower?
High input impedadnce, low output inpedance; in other words, a circuit capable of decouple a circuit from previous stage to the following stage, delivering the voltage signal ahead with no load effect from any side. Didn't you find that information anywhere?
 

dick_freebird

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Even attaching an inverter could have undesirable
influence on the clock quality, Miller kick-back can
"de-Q" the tank. A linear voltage follower does not
have the Miller feedback, the drains are pinned and
the sources move in tandem with the gate.
 

FvM

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I notice that the referenced previous thread is talking about "a 32 kilohertz crystal oscillator" without ever specifying it in detail. In so far all answers referring to the loading capability and output level of the oscillator are more or less guesses.

Before of continuing guesses, we should here a word about the oscillator type. 74ls294 will e.g. require a square wave input with sufficient level and fast edges.
 

sanjue

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The simple understanding is impedance matching
 

Audioguru

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The extremely low output impedance of a buffer is never used for impedance "matching", instead it is used so that its output voltage is not "loaded down" and can be used to drive a filter circuit that needs a low impedance input driver.
 

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