TMS320F28377S: VCO frequency

Dirk Zenker

Part Number: TMS320F28377S
Other Parts Discussed in Thread: AM5728

Hallo,

we have trouble with the PLL that sometimes does not lock.

The datasheet says the VCO frequency must be in a range specified in the datasheet, see the following picture.

When searching the datasheet I did not found the specified range for the VCO frequency.

Can you please point out where in the datasheet tms320f28377s.pdf the VCO frequency is specified.

Thank you.

0 Rajaravi Krishna Katta over 6 years ago

Hi,

What is the value of PLLRAWCLK frequency? Refer "Clocking System" figure in TRM.

Can you check if it is in the specified range. Look in table "Internal Clock frequencies" in Data sheet for the required range.

Thanks,

Katta

0 Joseph Casuga over 6 years ago in reply to Rajaravi Krishna Katta

Hi Dirk,

f(PLLRAWCLK) in the "Internal Clock Frequencies" section is VCO, in this case it is from 120MHz to 400MHz.

Regards,

Joseph

0 Dirk Zenker over 6 years ago in reply to Joseph Casuga

Hallo Joseph,

That explains much. Thank you very much!

We tried to reach an exact 192 MHz with a 20 MHz external oscillator since our SCI shall communicate with a AM5728 at 12.0 MHz.

And we got beyound the range.

Regards Dirk

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