Tool/software:
In the datasheet there are phase noise characteristics and jitter numbers, but noting about which outputs and mux settings.
Is 6:1 more noisy than 2:1 Output Channel Muxes ?
I want to use the BAW resonator for the lowest possible phase noise/jitter, but which outputs and muxes should I use to achieve this?
Hi Kjell,
BAW VCO3 is routed to all outputs and it has the best jitter compared to APLL2 and APLL1. Note that the output frequencies need to be in integer relation to BAW VCO3 2457.6 MHz such as 491.52 MHz, 122.88 MHz, 30.72 MHz, etc. Non-integer relation to VCO3 would be generated by APLL2/APLL1 which have wider frequency tuning ranges.
OUT4 to OUT13 would have better jitter performance compared to OUT0 to OUT3 due to their output buffers and physical locations.
Please share your requirements (frequency, clock format, jitter specs, etc.) so I recommend the frequency plan.
-Riley
Hi Kjell,
Choosing OUT5-OUT7 or OUT8-OUT13 is depending on number of outputs and frequencies. Output buffers on these are similar so performance is very likely the same. However, some outputs with physical location a little closer to power rails or input pins might get spurious impact so choosing outputs that are further away would help. Or between different frequencies, leaving an adjacent output in between helps reduce crosstalk.
OUT2-OUT3 have individual output dividers (CHDIV) so they are more flexible than other output pairs (OUT4-OUT5, OUT6-OUT7, etc. have the same CHDIV) in generating different frequencies from the same APLL source. However, they do not have SYSREF dividers.
-Riley
