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Varicap @ mV or even µV?

Moritz

Dec 12, 2015
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Hi there,

I'm curious. Do varicaps exists, that can operate with mV or even µV?
And what should I search for?

Thanks and best regards,
Moritz
 

davenn

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Sep 5, 2009
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hi there
varicap diodes, I assume you are referring to ?

what is your application ?
 

Moritz

Dec 12, 2015
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Yes, I'm referring to variable capacity diodes.

And I can't really tell you what I'm intending to do. Junst wondering if there are any, that can change theire capacity by milivolts of DC bias?
 

davenn

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you would have to look at the datasheets for specific types to get an idea
of their change in capacitance relative to the voltage ... that data will be graphed
and they will all be different


Dave
 

Moritz

Dec 12, 2015
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Yeah, I know that, that's why I'm asking. Because the datasheets I previously looked at don't have any data below several hundred of milivolts. So I'm wondering if maybe you guys know some varicaps that can operate in such magnitude of voltage...
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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well, they will very definitely resound to a signal in the millivolt or microvolt range, but this would need to be added to a constant voltage, and the amount of variation would be tiny.

Amplifying that small signal before applying it tho the diode would allow you to change the capacitance more.

The reason you need a relatively large voltage change to affect the capacitance is that you don't want the signal itself to change the capacitance (typically).

If your control voltage was significant at a might change then your signal would need to be even smaller.
 

dorke

Jun 20, 2015
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Moritz,
What is the frequency range you are going to operate at?
 

davenn

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Moritz,
What is the frequency range you are going to operate at?

asked him for application and got this as a reply .....

And I can't really tell you what I'm intending to do.


cant ?, don't want to ? something else ??
If you want our help, you need to help us in a better way


Dave
 
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