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LAUNCHXL-CC1352P: XOSC cap array delta value range

Evgenii Shvyrev
Prodigy 20 points

Part Number: LAUNCHXL-CC1352P
Other Parts Discussed in Thread: SYSCONFIG, CC1352P

Hello!
SW:
ccs1020
simplelink_cc13x2_26x2_sdk_5_10_00_48

I have some questions regarding TI CC1352P-2 XOSC HF capacitor array delta value.

1. Could you please let me know what is an acceptable range for the calibration value passed to OSC_AdjustXoscHfCapArray function?

2. Also, we use default calibration value 0xC1 which is the value recommended by the TI SysConfig tool, is it OK to use the value as a default value or another value should be picked up?

3. In the case of a custom board with CC1352P SoC, would it be better to pick up cap array delta specific for the board or we can use the value recommended by TI SysConfig tool?

Best regards,

Evgenii

  • 0
    TI__Guru**** 317180 points

    A crystal has a given Cload requirement given in the xtal datasheet. The load cap is Cpar + Cintloadcap (see section 6.3 and onwards in https://www.ti.com/lit/pdf/swra640) where Cintloadcap is the value you set with the internal cap value. Since it's difficult to know exactly the parasitic on a given PCB the typical is tune do trial and error on some boards where the cap array is changed and the output frequency is monitored. You want the output frequency to be as close as possible to the programmed frequency. 

    1) The range could be found in table 7 in the app note referred to above,

    2) / 3) The value should be adjusted according to the xtal and the PCB used.