Frequency Multiplier Chips

[MoltenVoltage]

I've been researching frequency multiplier chips and have a few possibilities.  They are quite a bit more expensive that I would have guessed.

I was wondering if anyone has used them and can recommend some good ones.  The output needs to be about 20MHz.  Input about half that.

I also haven't been able to find any that are variable across a particular range - do they exist?

Thanks!

[JKowalski]

PLL + a frequency divider? That should be pretty cheap, but I'm not completely sure how high the prices go for the high frequency ones.

Unless you already looked into that option, of course....

As far as variable in the sense of non-multiple variance, I have never heard of such a thing. 

[earthtonesaudio]

Hmm... Green Ringer with ultrafast diodes?   

[JKowalski]

Have a look at these:

http://focus.ti.com/lit/ds/symlink/cdc706.pdf

http://www.mouser.com/Semiconductors/Integrated-Circuits-ICs/Clock-Timer-ICs-Analog/Clock-Synthesizer-Jitter-Management/_/N-6j74b/?Ns=Pricing|0

No non-SMD components, but they seem to be exactly what you are looking for.

[MoltenVoltage]

Thanks Chris.

Now I just need to figure out how to use I2C.  It doesn't look that tough.

I had been looking at frequency doublers which are about $30 each.  These are still $8 each, but that's an improvement.

I also found this article which tells you how to build a doubler using diodes and transformers:
www.techlib.com/files/diodedbl.pdf

I need to double a uC output, but it would be interesting to send an audio signal through and see what happens.   Maybe some sort of octave effect like Alex is thinking?

[earthtonesaudio]

You didn't say anything about duty cycle, waveform, etc. so...

Use this:
http://www.fairchildsemi.com/pf/74/74VHC86.html

...and use one gate as the XOR, other 3 as inverters (or buffers) to make the delay line as per this:
http://www.maxim-ic.com/appnotes.cfm/an_pk/881

Total parts: 1
Total cost: $0.39 (in stock in SOIC package at Digikey: http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=74VHC86M-ND )

[borman09]

I can't get the waveform correctly.I try to do it.Thanks