AD7730L above 2.4576 MHz Clock Speed

Hi, 

It is possible to run the AD7730L at 4.9152MHz since it does not exceed the 5MHz max limit. But keep in mind that running the AD7730L at 4.9152MHz will not give the optimal performance compared to AD7730 only. Since its specified frequency should be at 2.4576MHz. 

Regards,

Andrei

Hi Andrei,

Thank you for the reply, to make sure I understand, I know the AD7730L will have more noise, etc. than the AD7730 generally.  Are you saying that it will also perform worse at 4.9152MHz than the datasheet performance in Table XXI in the datasheet, since that assumes 2.4576MHz?

For example, if we have 2 setups:

AD7730L at +/-10mV, CHP=1, and 100Hz Data Rate with 2.4576MHz clock
AD7730L at +/-10mV, CHP=1, and 100Hz Data Rate with 4.9152MHz clock

I expect the first to have 130nV RMS noise from that table, will the second have worse performance?

Thanks,

-chester

Hi, Chester. 

That Master Clock Range looks to be a mistake or should not be recommended for AD7730L.

The ADC/PGA is probably still functional at 25C with a clock 2X faster than what’s expected, but the accuracy will likely be poor, especially if temperature changes.

Thanks,

Jellenie

Thank you! This is very important to know, we'll test with 2.4576MHz and new filter values.

Thank you! This is very important to know, we'll test with 2.4576MHz and new filter values.