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DAC vs digital potentiometer

Cirkit

Oct 28, 2015
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What is the advantage of using a DAC over a digital potentiometer?

If the digital potentiometer is supplied from a stable regulated supply, is it not serving the same purpose as a DAC?

I understand that a DAC may be faster however, for applications where a fixed voltage is set at power on would a digital potentiometer be adequate?
 

Harald Kapp

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A digital potentiometer is uses, as the name says, as a potentiometer to attenuate a signal. The number of steps is usually limited, e.g. 128 or 256 steps (examples). Alos available with logarithmic characteristic for audio applications (e.g. digital volume control).

A DAC on the other hand is used to convert a digital signal into an analog representation of the digital signal. Resolution is often 10, 12, 14 or 16 bits or even more. Much higher than a typical digital pot. Also usually linear (although variants with non-linear characteristics also exist). DACs are typically used to generate a signal, not to attenuate a signal (although multiplying DACs can be used for the latter purpose, too).

for applications where a fixed voltage is set at power on would a digital potentiometer be adequate?
If the resolution and accuracy of the digital pot are good enough for the application: yes.
 

dragon

Oct 31, 2022
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Why do you need digital values when analogue ones work so good already!
I think its a problem with the industry these days.
 

Cirkit

Oct 28, 2015
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I want the ability to set the same value at power on or be able to adjust it in software. I did think about using a standard analogue potentiometer however, this may drift and requires careful manual adjustment.
 

dragon

Oct 31, 2022
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Maybe they are a bit fiddly. but pots dont drift thats only analogue delay lines that do that for example. (each time they feed-back.)

-edit- software adjusted pots would be pretty spiffy. -edit-
 
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crutschow

May 7, 2021
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I want the ability to set the same value at power on or be able to adjust it in software
So what resolution/accuracy do you need for that adjustment.
That may well determine whether to use a digital pot or a multiplying DAC.

What signal frequencies are involved?
 
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