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DS90CR288A - What happens if VCC pin could not meet noise level <100mV ?

Kawai
Guru 19785 points
Other Parts Discussed in Thread: DS90CR288A

Hello Team,

Our customer current design of DS90CR288A could not meet the noise requirement of <100mV for VCC pin (Pin 31,40,48,56).

I believe these pin are supply for TTL logic, so, may not be critical. However, what kind of problem would occur if the user could not meet this requirement ?

PLL_VCC and LVDS_VCC noise level is satisfying this requirement, just VCC supply noise level is around 150mV.

Best Regards,

Kawai

  • 0
    TI__Mastermind 29655 points
    Hi Kawai-san,

    If the supply noise voltage level for Vcc (as opposed to PLL Vcc and LVDS Vcc) is greater than 100 mVpp, then this may cause issues with the noise coupling onto the output of the parallel data. We do not have characterization data to determine the resulting device behavior in the presence of over 100 mVpp supply noise, though I agree with your opinion that this is the least sensitive of the 3 Vcc power supplies, so the system may still be able to function anyway.

    Nevertheless, please request the customer to add the necessary decoupling caps or ferrite bead to the supply line to help bring the Vcc supply noise level to within the recommended supply noise specifications. We cannot guarantee proper behavior of the device when operated beyond the recommended operating conditions.

    Thanks,

    Michael
  • 0 in reply to Michael Lu (Santa Clara)
    Guru 19785 points
    Hello Michael-san,

    Thank you very much for your opinion.
    I will ask customer for sufficient evaluation.

    Best Regards,
    Kawai