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ESD321: Correlation between ESD protective devices, junction capacitance, and electrostatic testing requirements

Tonyx.wu
Expert 2545 points
Part Number: ESD321

As shown in the figure below, there is a significant difference in the ESD junction capacitance for the USB interface in TI's ESD protection devices. With different IEC 61000-4-2 electrostatic testing conditions, the recommended ESD diode junction capacitance also varies;

Please help confirm if the static electricity testing requirements are different, and the corresponding junction capacitance is also different. Thank you;

  • 0
    TI__Expert 4830 points

    Hi Tonyx.wu,

    Just to clarify, this table depicts the specifications of our devices, not the requirements for USB applications. The IEC rating and the Capacitance values are respective to each device. For instance, TPD1E10B06DPY has an IEC rating of 30kV contact and 30kV air gap, and a parasitic capacitance of 12pF. Similarly, ESD321DPY has an IEC rating of 30kV contact/air gap, and a parasitic capacitance of 1pF. Both of these values are dependent on the internal die process, and are not necessarily related to each other.

    Please let me know if you have any questions!

    Best Regards,

    Josh Prushing

  • 0 in reply to Josh Prushing
    Expert 2545 points

    is it OK to be sure there is no correlation?i need detail whether the ESD diode's static level has relevance on the junction capacitance of the diode. We need a positive reply. Thank you.

  • 0 in reply to Tonyx.wu
    Expert 2545 points

    Please help confirm again whether there is a correlation between the ESD level and the junction capacitance of the ESD diode;



    As shown in the figure, USB3.2 usually requires the junction capacitance of ESD diodes to be very small, such as 0.1pf or 0.2pf. However, the capacitance of this diode reaches 12pF, which may affect the integrity of the USB3.2 signal. However, this diode can withstand the specification of 30KV/30KV, so I have repeatedly asked if there is a correlation between ESD level and junction capacitance

  • 0 in reply to Tonyx.wu
    TI__Expert 4830 points

    Hi Tonyx.wu,

    Using TI's product selection tool, I have filtered the working voltage to show only 3-5V devices. As shown in the image below, for the devices with a 30kV IEC contact rating, the capacitance varies from as low as 0.5pF to as high as 19pF. 

    Capacitance for these devices is determined by the internal die, not the ESD rating. Inversely, the ESD rating is also not determined by the capacitance of the device. For a small selection of devices, they may appear to be correlated, but looking across the portfolio, the ESD rating does not have any relevance on the capacitance of the diode.

    I hope this helps to clear up any confusion, please let me know if you have any additional questions!

    Best Regards,

    Josh Prushing