CC1350: CC1350 Frequency Offset Issue

Chad Winterhof

Part Number: CC1350

I have a frequency offset issue on my CC1350. I am at an unmodulated 868 Mhz transmit using the Smart RF studio connected to my customer CC1350 design.

I have read about the CLoad on the 24 MHz clock. It was at 12 pF and it was a 76 kHz offset. I changed it to 5.6 pF and it went to a 41 kHz offset. The third time I removed all capacitance and it was still a 24 kHz offset.

Am I missing a clock setting or a calibration step?

over 7 years ago

0 TER over 7 years ago

TI__Guru**** 317180 points

- Note that CC1350 has a built in load cap array. See processors.wiki.ti.com/.../CC26xx_Tips_and_Tricks
- What is the Cload spec on the xtal you are using?
- Is it + or - 24 kHz compared to the expected frequency?

0 Chad Winterhof over 7 years ago in reply to TER

Prodigy 20 points

The spec on the crystal was from Kyocera a 24 MHz 15 PPM crystal. -40 to + 85C. The frequency is -24 kHz less than the 868 MHz expected.

0 TER over 7 years ago in reply to Chad Winterhof

TI__Guru**** 317180 points

I asked about the Cload spec of the xtal.

Try to adjust the internal cap array one value down (you need slightly lower cap)

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CC1350: CC1350 Frequency Offset Issue