Need a little help with sine input on CXA1645

Started by grahf, June 18, 2006, 03:09:23 AM

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grahf

Ive been working on an RGB to S-video circuit with a CXA1545M for my PC Engine. Ive been researching this and a few electronics sites, and ive learned a lot. Just want to thank the regular posters here first and foremost.

Ive got pretty much everything figured out (i think anyhow :D ), except for the SINE input on pin 6. I know im going to need a 3.58mhz signal. I am just unsure how to go about building that part. I know i can use a crystal or an oscillator. If i go with a crystal, is there a circuit out there i can look at on how to do it? If an oscillator is better, can anyone recommend a good one?

Thanks in advance.
-Ben

viletim!

As you say, you can build a crystal oscillator or buy an oscillator module. The modules are small metal boxes with three (connected) legs - one for power, one for ground, one for signal output - easy! The downside is they're  a bit harder to find than normal crystals and more expensive. I can easily buy a 4.43Mhz osc module localy (PAL land) so I doubt you'll have much trouble finding a 3.58 Mhz one where you live.


grahf

Thanks for the help, and the link. I have found an IC which i think may do the trick: The MAX7357 (specifically the MAX7373AXR365). This looks like it may do the trick.  The data sheet is: http://pdfserv.maxim-ic.com/en/ds/MAX7375.pdf

Can you see any reason why this would not work for me? I have been unable to find a suitable oscillator module, but this claims to be a replacement. Thanks for any comments.  

viletim!

A silicon oscillator? I supose it'd be fine if you can get one...

If you don't understand the info at the link on crystal oscillators I pointed at then there's an easy to build osc circuit in the ad725 datasheet you might want to try.

viletim!

...just reaslised that that the values of that circuit are for 4*osc freq. Better try an R2 of something like 1.5k instead of 200 ohms.

grahf

I was able to order two samples of the MAX7373AXR365. I will test it out to the best of my ability, and post my findings for others if it does or doesnt work. Im hoping it does, since it would be such a simple solution.

If it doesnt, I think i should be ok with one of the circuits. This stuff is all getting clearer to me as time goes by.