DS90UB954-Q1: Crystal Recommendations

Hi Muk,

The capacitive load of the crystal should come from the crystal vendor.  I would recommend reaching out to them for the correct capacitor values to use in this application.

Regards,

Nick

Hi Nick-san,

Their quesion is,

Can they use the 8pF crystal? or Do they have to use the 18pF crystal?

They are understanding, TI recomend 18pF crystal. However they want to use 8pF since availability&supply issues.

Muk

Hi Muk,

18pF is what we use but as long as the clock source is clean and meets our spec then 8pF will work fine.  This should be something to ask the crystal vendor though to make sure the crystal will work with 8pF.

Regards,

Nick

Hi Nick-san,

Could you please let me know the floating capacitance value on the IC oscillator circuit side? If it is possible, they want to know typical value and max value.

They need this value for capacitor selection and estimation.

Thanks

Muk

Hi Muk,

I will need a few days to look into this to provide more information.

Regards,

Nick

HI Nick,

Do you have any update?

Thanks

Muk

Hi Muk,

The only thing I can say is that capacitive loading needs to be determined by the crystal vendor.  It is not up to us to determine the best way to load the crystal.  In section 7.4.5 it says immediately after the recommendation of 18pF that the value will very with the crystal used.

Regards,

Nick