10-20 MHz low power PLL 1

[bassfisher]

I'm looking for a low power PLL to generate a couple different clock frequencies from a single reference. Needs to be fractional N. Need 12 an 16.384MHZ am having trouble finding anything suitable. Any recommendations?

 

[nbucska]

What is "12" ? What are the frequencies, accuracy you need,
etc. Every omitted data may cost a LOT...

<nbucska@pcperipherals DOT com> subj: eng-tips

 

[bassfisher]

12 MHZ - sorry. Accuracy will come from the reference. This is a new design with the main requirement that we coherently generate both of these two clock frequencies. The reference frequency is open too - although it'd probably be easiest to start with 12 MHz as the reference and generate 16.384 from that.

There are plenty of low power synthesizer chips at VHF,UHF and microwave frequencies but am having trouble finding anything integrated in this range.

 

[nbucska]

E-mail me the specs and we will see...
Fractional-N may not be the simplest -- e.g. once I have
made a frequency divider (by 625) with 4 transistors and
a few discrete parts...

Do you need coherency only to avoid metastability ?
Is your application all digital ? What does the analog
do?




<nbucska@pcperipherals DOT com> subj: eng-tips

 

[melone]

Have you searched the ON semi, Toshiba, Fairchild, etc. websites? I believe I have seen PLL's on those sites.

 

[bassfisher]

Thank you for all the help - I found one

National LMX2350. It wasn't initially obvious because this is actually a dual part. One half supports microwave frequencies but it has an aux half that only uses 1 mA that will work in the frequency range I need.