Hi csr,
I use CSR1020 to made a PCB module, crystal use recommanded "EPSON Q22FA12800517xx".
when we test frequceny offset is over 50 ppm.
I want to ask,
1. can csr tool kit trim over 50ppm crystal?
2. if can't, can i loading capacitor make offset under 50ppm then use tool kit to trim the offset?
thanks.
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When using the recommended 32MHz XTAL, we should not expect the offset to be so high. The crystal datasheet mentions a 10ppm tolerance.
Please make sure to burn the Cubic Values provided in the Qualcomm® CSR102x Recommended Crystals Specification (80-CT924-1) in the appropriate PS key. This will ensure drift compensation across the temeprature range.
Its not possible to compensate for 50ppm deviation using internal trimming.
Please ensure that the module Harware design is done correctly. The XTAL traces are as short as possible and there are no traces below the XTAL.
Adding of external loading caps is not advised. The need to do this would indicate that the components are not working as per expecatation.