RE: SRRC certification test fail

ga0404 — Sat, 16 Mar 2019 01:37:19 GMT

Hi，ketiljo

Thank you for your reply.I have checked the CL value of the crystal from it's datasheet,and the value is 8pF,and I use 12pF load caps accordingly.

Now I guess the reason maybe the value of caps we use is not precise,the deviation may be ±5% or more.

RE: SRRC certification test fail

ketiljo — Fri, 15 Mar 2019 13:17:24 GMT

If the carrier frequency is off, it's load crystal load caps that have the wrong value. Look up the CL value of the crystal from it's datasheet and calculate the values (for each) as follows:

Ccap = CL * 2 - 4 pF

For a crystal with CL = 8 pF, the caps should be 8 pF * 2 - 4 pF = 12 pF each.

Round down to the closes value in case you need to.