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CDC7005 NRESET minimum pulse width

Ranji Bhola
Intellectual 1510 points
Other Parts Discussed in Thread: CDC7005, CDCM7005

Team,

We have a customer seeking the NRESET min pulse width for the CDC7005RGZR part. The datasheet specifies the NPD min, but not the min for the pulse with for NRESET.

Any information on this would be great.

Regards,

Ranji C. Bhola

 

 

 

  • 0
    TI__Expert 4150 points

    Ranji,

    the data sheet on page #4 (pin description for RESET) specifies a min pulse width of 5ns:

    RESET is not edge triggered and should have a pulse duration of at least 5 ns.

    Best Regards, Falk

  • 0 in reply to Fritz
    TI__Guru 71526 points

    Fritz,

      The statement you quoted is from the CDCM7005 datasheet, not the CDC7005; the CDC7005 states it is asynchronous, does not specify a MIN pulse time.  One might infer from the two datasheet descriptions of the i2C interface that they are the same, but there is no guarantee.  So at this time it is still an unknown; please see if you can find this info. 

    Additionally, clarification on the Tr and Tf times, stated as MAX of 4ns in the datasheet - does this mean 4ns is the fastest risetime acceptable, or does it mean it must be 4ns or less (e.g. 2ns is okay?).

    Thank,

    -Leonard

     

  • 0 in reply to LeonardEllis
    TI__Expert 4150 points

    Leonardo,

    The Tr Tf needs to be 4ns or less (preference is a faster, not slower signal).

     

    I will forward CDC7005 question to product champion. I am not sure if they will be back from vacation by next week.

    By the way, somebody called me earlier today about this question, and I recommended to use 10ns in absence of the exact number. I assume it's really 5ns, but to be save recommend at least 10ns time for reset.

    BR. Falk Alicke

  • 0 in reply to Fritz
    TI__Mastermind 20900 points

    Hello Leonard,

    The Reset circuit of both CDC7005 and CDCM7005 have the same implementation. Both are asynchronous and needs to have a minimum pulse width of 5 ns.

    Best regards,

    Julian