Part Number: TMS320F28235
Customer is using F28235 Q100 for their application. 20MHz external crystal is used.
Here are some doubts:
1) Can 20MHz be used? It should be OK.
2) What's the recommendation for CL and other specifications?
Thanks a lot.
The max PLL multipler is 10/2. You will only be able to achieve 100 MHz operation with a 20 MHz crystal. You can use 20 MHz with that restriction.
Normally, people use 30 MHz crystal with F28235 to achieve 150 MHz operation.
-----------------------------David M. AlterSenior Member Technical StaffTexas Instruments Inc.
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In reply to David M. Alter:
The parameters for the passive components vary based on the crystal chosen. Hence we do not recommend any values. Our datasheet has the following note:
TI recommends that customers have the resonator/crystal vendor characterize the operation of their device with the DSC chip. The resonator/crystal vendor has the equipment and expertise to tune the tank circuit. The vendor can also advise the customer regarding the proper tank component values that will produce proper start-up and stability over the entire operating range.
Hareesh J, C2000 Microcontroller Applications, Texas Instruments.
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