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DS110DF111 - SMBus Data Hold Time

Kawai
Guru 19785 points
Other Parts Discussed in Thread: DS110DF111

Our customer is using DS110DF111, but in their SMBus access, they cannot meet the Maximum of Data Hold TIme(T_HD;DAT MAX).

Datasheet have T_HD;DAT MAX = 0.9us, but our customer currently cannnot meet this spec.
In their evaluation, I2C communication has no errors.

I understand the clock rate is different, but, SMBus Specification ver 2.0 do not have maximum definition for data hold time.

[Question 1]
To support the normal SMBus communication with DS11DF111, is  "T_HD;DAT  MAX"  a must specification to be followed ?

Best Regards,
Kawai

  • 0
    TI__Intellectual 1985 points

    Hi Kawai,

    When you say the customer cannot meet the hold time spec, do you mean their hold time is greater than 0.9us? What is their hold time?

    Regards,

    Casey

  • 0 in reply to Casey Morrison
    Guru 19785 points

    Hi Casey-san,

    Thank you for your reply.

    Yes, our customer's hold time is 1.75us.

    Why is this Data Hold Time MAX is defined in the datasheet, which is not defined in the SMBus 2.0 specification ?

    Best Regards,
    Kawai

  • 0 in reply to Kawai
    TI__Intellectual 1985 points

    Hi Kawai,

    I received some more clarification on the timing parameters in question. The 0.9us (max) data hold time listed in the "Recommended Timing for the Serial Bus Interface" section of the Electrical Characteristics table comes from Table 5 of the I2C bus specification, version 2.1. For the DS110DF111, as long as you meet the setup time requirement (>100ns), you will be fine and you do not need to guarantee a hold time of <0.9us. There may be other devices on the I2C bus which require <0.9us hold time, but I see that in later versions (UM10204, Rev5, 9 October 2012), they have removed this 0.9us max requirement.

    Regards,

    Casey

  • 0 in reply to Casey Morrison
    Guru 19785 points

    Casey-san,

    Thank you very much.

    Best Regards,
    Kawai