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DRV2605: I2C Interface not addressable

Franz Schellhase
Expert 3605 points
Part Number: DRV2605

Hi Team,

can you help my customer with their inquiry, please?

In this specific case, we use the type DRV2605LYZF.
Unfortunately, the module is not addressable when communicating via the I2C interface. As possible cause I suspect a too low voltage (approx. 1.3V) at the Vreg pin, see also oscilloscope screenshot.
In this oscilloscope screenshot, the yellow line is the voltage Vdd and the green line Vreg.

Vdd rises to 3.6V within about 600µs. This should be above the required slew rate of 3.6kV/s. The enable line is connected to Vdd.

Maybe you have a hint for me?


Thank you,

Franz

  • 0
    TI__Guru* 84915 points

    Hi, Franz,

    I have some questions to have a better approach to this issue.

    - Do you have a circuit schematic? This would be helpful to understand the 1.3V at the REG pin.

    - In addition, do you know if this issue is reproducible 100% of times. I mean, does this also happen with many samples?

    Any other information you could provide will be appreciated.

    Best regards,
    Luis Fernando Rodríguez S.

  • 0 in reply to Luis Fernando Rodriguez S.
    TI__Expert 3605 points

    Hi Luis,

    Thank you for looking into this.

    • I sent the schematic via email.
    • The phenomenon occurs in about 10% of the boards, with these it is reproducible.

    Best regards,

    Franz

  • 0 in reply to Franz Schellhase
    TI__Guru* 84915 points

    Hi, Franz,

    Thank you for providing the circuit schematic and the details about the failure rate.

    I have some additional questions.

    - Does the issue still appear when the customer disconnects the rest of devices from the I2C lines and the DRV2605 output lines? I mean, if he isolates the DRV2605 from the rest of components, does this issue still appear?

    - If the customer replace the DRV2605 unit on the bad board for a new one, does this issue still appear?

    - If the customer takes the DRV2605 unit from the bad board and test it on a good one, does this issue appear?

    Please let me know if you have any question or comment about this.

    Best regards,
    Luis Fernando Rodríguez S.

  • 0 in reply to Luis Fernando Rodriguez S.
    TI__Expert 3605 points

    Hi Luis,

    They didn't do that yet, but it's planned. I'll let you know when they have results. Do you have any leads in the meantime?

    Thanks,

    Franz

  • 0 in reply to Franz Schellhase
    TI__Guru* 84915 points

    Hi, Franz,

    I would like to verify if the I2C communication is being affected by the additional devices sharing the DRV2605 lines. Usually, these issues are associated to a high capacitance level in the communication lines. Please let me know when they have these results in order to see how to proceed.

    Thank you.

    Best regards,
    Luis Fernando Rodríguez S.