C0 in the nRF51 XO spec

[Jungo88]

Hi team,

Let me confirm what's C0 in the nRF51 32MHz XO spec. It specifies as following but C0 definition cannot be found in the PS. I assume C0 is the load cap where C1 and C2 in the Fig7 below are the same. Am I correct?

RS,X32M Equivalent series resistance.

C0 ≤ 7 pF, CL,MAX ≤ 12 pF

C0 ≤ 5 pF, CL,MAX ≤ 12 pF

C0 ≤ 3 pF, CL,MAX ≤ 9 pF

Thanks and regards,

Jungo

[Håkon Alseth]

Hi,

 

C0 is the shunt capacitance of the crystal, which is normally quite low (~1 pF).

Here's an example equivilant circuit of a crystal, where C0 is shown (borrowed from the wiki article):

 

The C0 parameter shall be found in the datasheet for your chosen crystal part.

 

Best regards,

Håkon

[Jungo88]

Thanks Hakon.

Noted that C0 is from equivalent crystal model.

Jungo