AD725 input crystal frequency options

hello

the problem is when designing boards and making them with pcb makers, it is better to have digikey\mouser stock for sure.

do we really need level translators?? I think someone years ago mentioned it does not, and it can run 3.3v just fine. please check.

assuming I use that mems oscillator in good conditions, like just room temperature. what could go wrong?

According to the AD725 spec Vih_min = 2V with Vcc=+5V.  As stated above, as long as the oscillator output exceeds 2V then it should work.

I understand the issues with part availability, I face them all the time.  

It is recommended to use oscillators for the 4FSC input for accuracy and stability issues.  Of course you can design the system anyway you want to.  Personally I'd will not use MEMs because of potential problems.

hello

can you post a suitable crystal number from a good supplier rather that digikey and mouser?

is there also another option? like frequency dividers and so on?

Digikey/Mouser are just distributors, they don't make oscillators or crystals.  I've spec'd Abracon, ECS, Epson to name a few.  Start by selecting the target frequecy, then ppm, then voltage, then package.  Filter again those and you will find a series you like.  For example if you need a 17.73MHz oscillator and it's not stocked by digikey and you like the Abracon ASFL1  voltage/package then you can order the exact part from from Abracon.  It may take a bit of time but it is doable.  There are lots of options taht need to be sorted through depending on you system

If you find a oscillator that's an integer multiple of the target frequency then you can use dividers.  Fractional divider can introduce jitter via the PLL.  There are some fractional divider that should work but they be more expensive that just a plan oscillator.

hello

i found this one for PAL: https://www.digikey.com/en/products/detail/epson/SG-8018CG-17-734475M-TJHPA0/13661534

it is non-stocked in digikey but mouser allows to buy it: https://eu.mouser.com/ProductDetail/Epson-Timing/SG-8018CG-17.734475M-TJHPA0?qs=zW32dvEIR3sW4Eud%252Bsosow%3D%3D

so based on datasheet, the crystal is outputting its frequency when OE pin is High and it doesn't when OE pin is Low. right? and similar functionality for the NTSC crystal linked above,,, please check if my circuit can work or need some tweaks.

The part should work.  Note I see 20 week lead time  on the part.  You might contact the manufacturer direct.

Pulling OE high will enable the output.  Note that the OE pin has a weak pull down so you'll need a pull up to 3.3V.  10k will work fine.

hello

what does "weak pulldown" even mean? I will pull it up to 3.3v using 10k or similar for sure, that is when I want it to be active. but when not active I pull it down to 0v using 10k as seen in my picture above. please check.

lead time is ok for now since first step is making a test board.

I am still waiting answers to other questions I posted in this section though.