I found that the demo board of IMX8QM and IMX8QXP,
the 24MHz main crystal and RTC 32.768KHz crystal does not place load capacitor, is it ok for the system? why imx8Qm/QXP don't need the capacitor but IMX8M placed that capacitor?
2x22uF capacitors are recommended instead of 47uF. Not only total capacitance is a concern, but also frequency response of the impedance. As for the quantities of the decoupling capacitors, please follow our 8QXP decoupling recommendations from 8QM/8QXP Hardware Development Guide with one exception: VDD_DDR_VDDQ decoupling scheme should be adopted from the DDR3L validation board.
And I would have one additional comment which is more layout related. For the PMIC power rails, it is best to place all the bulk capacitors as near to the processor as possible (and not next to the inductors). Then route the FB trace from the point of the closest bulk capacitor (to the PMIC) as a separate trace back to the PMIC. This will ensure maximum voltage accuracy at the process.
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