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Design >> Mixed-Signal Design >> hartley oscillator - best approach
https://designers-guide.org/forum/YaBB.pl?num=1160039223

Message started by trond on Oct 5^th, 2006, 2:07am

Title: hartley oscillator - best approach
Post by trond on Oct 5^th, 2006, 2:07am

I would like to build a circuit for a hartley oscillator and was wondering what design to best go for. The frequency should be around 500MHz. So I was thinking about whether to use discrete components and use an ugly board construction.

See http://users.easystreet.com/w7zoi/bboard.html as an example.

Or should I rather go and use a chip to which I can attach external cpacitors/inductors.
See MAX2622 datasheet. (This is based on a Colpitts oscillator, but I need to use a hartley configuration)

What do you guys think. Can anyone give some recommendations?
One more thing, I have to use a pretty large external capacitance of 60pF in the Hartley configuration, meaning the inductor would have to be <1.7nH for 500MHz. Is that possible at all? I mean can I get the oscillator to oscillate to 500MHz with such a big capacitance?

Cheers

Title: Re: hartley oscillator - best approach
Post by trond on Oct 9^th, 2006, 2:59am

So I thought about a suitable way to implement an Hartley osc. easily and would like to use the Max2620.
The first picture shows the chip as a common-collector Colpitt oscillator.
My questions is whether I can use the Max2620 for an hartley oscillator with a configuration shown in the second picture? Of course I would need a capacitor connected to pin 2, but is there anything else I need to consider?

Cheers