the PLL error of the s32k312 in ppm

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the PLL error of the s32k312 in ppm

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dongyong1
Contributor I

Dear NXP Engineers

 

I would like to know what is the PLL error of the s32k312 in ppm

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VaneB
NXP TechSupport
NXP TechSupport

Hi @dongyong1 

Sorry for the inconvenience this may cause. 

All information related to the PLL jitter is provided in Table 41 of the S32K3xx Data Sheet, Rev. 8.

 

B.R.

VaneB

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dongyong1
Contributor I

Hi VaneB

take the last line of Table41 as an example(1680ps 120Mhz). Is it possible to calculate like this: 1/120MHZ=8.3ns, 1680ps/8.3ns=0.2. (0.2/120M)*1000000=0.002ppm

dongyong1_0-1692841739259.png

 

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VaneB
NXP TechSupport
NXP TechSupport

Hi @dongyong1 

These two specs are about entirely different things. So, I think converting the ps to ppm is not possible. 

Frequency is the number of cycles executed per second. Otherwise, the jitter is about the variance of the clock period. So, if your clock period varies randomly by 10ns RMS (for example), but the period is still 1µs on average, then you can have a very accurate (but jittery) 1MHz clock.

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dongyong1
Contributor I
Hi @VaneB

Is that right?
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