TMS320F28377D: TMS320F28377D f(OCI) changes from 30Mhz to 20Mhz

Hello Simen,

I don't see a picture. Also I am not quite clear on what you are asking. Are you stating that the XTAL frequency you are using is 25MHz?

If so, 25MHz is not within the range of valid XTAL frequencies for the F28377D.

Best Regards,
Adam Dunhoft

Adam,

In F28377D datasheet(SPRS880B), we say the max frequency from external oscillator(PLL enabled) is 30MHz. And, we modify this max frequency from 30MHz to 20MHz in datasheet SPRS880C.

Since my customer already released some products to market, they want to know what is the risk if they used 25MHz external oscillator and enable PLL funciton?

Please advise your idea, thanks for help.

Best regards,
Luke Chen

Hello Luke,

Let me dig into this. I want to make sure that the 20MHz is a hard limit.

Best Regards,
Adam Dunhoft

Hello Luke,

25MHz will work. We will update the f(X1) (PLL Enabled) spec to a MAX of 25MHz in the next release of the datasheet.

Best Regards,
Adam Dunhoft

Hi Adam,

Thanks for your response.

Please help us to know more about this, what is the reason we modified the Max frequency(PLL enabled) from 30MHz to 25MHz/20MHz?

Best regards,
Luke Chen

Hello Luke,

It was made to match the XTAL input max, but does not require the internal XTAL circuit for operation. The max input frequency for the PLL should be 25MHz.

Best Regards,
Adam Dunhoft