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ISO1430: want to reduce current/power on bus-side.

Motoyasu Hattori
Genius 11145 points
Part Number: ISO1430

Hi,

According to the application note, SLLA453A, we can find the added 10ohm series resistors.

By using these resistors, A-B impedance is 54ohm(Bus transmission) + 10ohmx2 = 74ohm.  So we reduce current on ISO143x bus-side against no use series resistors. Is my understanding correct?   Please let us know.

Thanks and best regards,
M.HATTORI.

  • 0
    TI__Guru 55815 points

    Hi Hattori-san,

    Thanks for reaching out.

    The reason for using 10Ω series resistors is not for reducing device current consumption but to limit the voltage that appears at A/B pins of device when there are EMI transients on the bus like ESD, EFT and Surge

    TVS diodes typically have large variation in clamping voltage specification which can exceed device absolute maximum rating. To mitigate this, a 10Ω resistor is used in series which drops additional voltage and reduces the voltage that appears on A/B pins after the TVS diode when there is EMI transient. The 10Ω series resistor in addition to the TVS diode provides a more robust protection than with just the TVS diode, and also makes sure the device absolute maximum ratings are not exceeded.

    Let me know if this answers your question, thanks.


    Regards,
    Koteshwar Rao