• Resolved

LP5569: I2C fall time specification problem

Prodigy 110 points

Replies: 5

Views: 88

Part Number: LP5569

Hello,

I plan to use LP 5569, but I have a problem with the fall time specification.

The specification of I2C fall time is MIN. 15+0.1Cb ns of LP5569.

Since the master side is a 1.8V system(pull-up at 1.8V).
In the following I2C spec, the fall time spec at 1.8 V is min. 6.5 ns, which does not match LP 5569.

Does this spec mean that LP5569 won't match on a 1.8 V system?

Please consider changing the spec of fall time.

I checked the Q &A in the past , I think there is no problem if it is longer than 5ns.

e2e.ti.com/.../729166

Best regards,

Hyodo

  • Hi Hyodo,

    Maybe LP5569 can work normally even the fall time is small than spec. But we didn't suggest our customer to use them in such situation because we can't guarantee the device will work  stable under continuous working condition.

    Best Regard 

    Monet Xu

  • In reply to Monet Xu:

    Hi ,Monet

    Thank you for your reply.

    I understand you can't guarantee it.

    Please tell me for reference.
    If this spec is not respected, what is the principle behind the instability?
    Is it a malfunction such as a communication error? Or will it damage the device?

    Best regards,

    Hyodo

  • In reply to user6519235:

    Hi Hyodo,

    The spec in the datasheet is verified by our designer and irregular using may cause the unexpected communication error.

    Best Regard

    Monet Xu

  • In reply to Monet Xu:

    Hi Monet,

    I'm sorry for the delay.

    So is it a recommendation to add capacitance to SDA(SCL), to keep this fall time min. spec?

    Best regards,

    Hyodo

  • In reply to user6519235:

    Hi Hyodo,

    The capacitance load for each line(SDA/SCL) will increase the minimum fall time spec. So it is not suggest to add a capacitance.

    Best Regards 

    Monet Xu