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TMP102: Question about t(HDDAT): Data Hold Time spec

Satoshi
Guru 19615 points
Part Number: TMP102

If there detailed tHDDAT spec for TMP102 below, please let me know about these specification.

・Is there tHDDAT variation for parts to parts, and lot to lot?

・Is tHDDAT have temperature coefficient?

　If yes, please see these spec.

I2C will choice fast mode.

When tHDDAT slightly less than 100ns, these condition is possible to affect the accuracy for data communication, correct?  

Best regards,

Satoshi

  • 0
    TI__Guru* 91206 points

    Dear Satoshi - 

    Thanks for posting! The I2C spec for I2C bus devices for this parameter essentially lists from 0sec + 300nSec for Fast mode for lower value and max 900nSec for upper value. We have not seen any issue with the TMP102 inside these values. If your MCU is holding data for only 100nSec, it is technically violating the I2C spec. 

    See notes 3 and 4 in the table labeled:  Characteristics of the SDA and SCL bus lines for Standard, Fast, and Fast-mode Plus I2C-bus devices

  • 0 in reply to Josh Wyatt
    Guru 19615 points

    Hi Josh

    Thank you for reply,

    ・TMP102 datasheet is described tHHDAT: 100ns_min ~ 900ns_max on page-6. (On Fast mode, timing diagram is Figure-7)

    　Which is correct the 0s+300ns or 100ns_min?

    　For example, if tHDDAT set about 15ns~40ns equal to violating the I2C spec, what is problem on I2C communication?

    　（TMP102 can not communication, feedback to master the wrong data format, etc）

    ・Please continue to consider about tHDDAT: 100ns and 900ns's IC to IC variation and temperature coefficient.

    Best regards,

    Satoshi

  • 0 in reply to Satoshi
    TI__Guru* 91206 points

    Satoshi - 

    What MCU are you using? 

  • 0 in reply to Josh Wyatt
    Guru 19615 points

    Hi Josh

    MCU is customer's in-house design, detailed spec is confidential.

    Is there critical relation for MCU and TMP102's timing spec?

    Please let me know confirming items for MCU specification, I will try to confirm these specification. 

    Best regards,

    Satoshi

  • 0 in reply to Satoshi
    TI__Guru* 91206 points

    Dear Satoshi - 

    I was wondering about the MCU because it is likely that the vendor (if it is one from a major IC company) has a datasheet and associated SDK with built in I2C peripheral code which can help the customer. These kinds of timings are not normal to be concerned with and we have no issues that we know of with our device.