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TMS320VC5507: TMS320VC5507PGE　CLKOUT accuracy

kenichiro sato
Prodigy 40 points
Part Number: TMS320VC5507

Tool/software:

Questions:
(1) What is the accuracy of the DPLL inside the DSP?
(2) Is it possible that CLKOUT fluctuates due to an internal defect in the DSP?
(3) What could be the cause of CLKOUT fluctuation?

Situation description:

It uses TMS320VC5507PGE.
Input 16.384MHz (±10ppm) from the external oscillator to DSP pin 13.
The clock is multiplied by 12 inside the DSP to operate at 196.608MHz.
(Register settings: PLL MULTI=24, PLL DIV=1)
I want to output 16.384MHz, which is 1/6 of 196.608MHz, to CLKOUT (pin 15).
Three of the four prototypes output 16.384MHz from CLKOUT.
One outputs 16.356MHz.
When the ambient temperature is below 10°C or above 30°C, 16.384MHz is output. At around 25°C, it becomes 16.356MHz.

-There are no soldering defects on the DSP pins.
-The external oscillator is stable at 16.384MHz. And there are no problems with the waveform.
-The noise of the 1.6V DSC power supply is the same as the other three units, so there is no problem.

  • 0
    TI__Mastermind 48235 points

    Hi Sato-san,

    I have forwarded your request to our HW apps team for further help. Due to the coming Thanksgiving holiday, our responses may be delayed.

    Best regards,

    Ming

  • 0 in reply to Ming Wei
    TI__Mastermind 21815 points

    Hi Sato-san,

    Unfortunately, we do not have an specification for the accuracy of the DPLL, other than mention a 

    A couple of questions for additional information:

    1. Is the frequency change gradual with temperature, or does it step between 16.384MHz and 16.356MHz?
    2. If you set the CLKOUT DIV to 1 and output the 196.608MHz DSP Clock on CLKOUT, does it show the 196.608MHz or does it show something different (across temperature)
    3. You mention the noise on the power supply is the same as the other units, but can you clarify what the noise level is?

    Thanks,
    Mike