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TPS2660: TPS2660:

user3784847
Prodigy 20 points
Part Number: TPS2660

Please refer to SLVA833 .

In page 3, when a ±500v, 2Ω surge pulse is applied, the input voltage in TVS D1 clamps to a ±44v maximum.

Question1: a ±500v, 2Ω surge pulse is applied, max current is about 250A?

Question2: what is the max current through D1 SMCJ28CA?

Thanks for your support!

  • 0
    TI__Genius 16305 points

    Hi,

    When 500V surge is applied with 2ohm, peak current will be 250A, but practically the cable impedance will be about 1ohm or 2 ohms (1 meter cable), practically you will see about 125A.

    Usually for 10/1000us Peak Pulse current spec is about 35A, but for 8/20uS pulse, it is about 169A at 59V. (ST Micro specifies in their datasheet, not every manufacturer does this)

    Please refer to ST micro datasheet, for 8/20uS peak pulse current rating.

    http://www.st.com/content/ccc/resource/technical/document/datasheet/ed/51/0b/1f/07/5e/42/1e/CD00001367.pdf/files/CD00001367.pdf/jcr:content/translations/en.CD00001367.pdf

    To calculate maximum clamping voltage at other surge level,use the following formula: VCLmax = VCL - RD x (IPP - IPPappli) where IPPappli is the surge current in the application.

    Here depending on the cable impedance (1 or 2 ohms), peak current could be about 125A in practise and using the above derating formula, clamp voltage will be about 50V.

    But again please note that we recommend 2.2uF at VIN-GND and this will take some enegy during surge.

    Considering all this, in practise clamping voltage will be about 44V.

    Let me know if you need further support through email "karikalan@ti.com". What is the end use case you are looking at?

    Regards,

    Kari.

  • 0 in reply to Karikalan Selvaraj
    Prodigy 20 points
    I still have some doubt.
    For this TPS2660 solution, DC power cable should be available for 20 AWG that is about 0.0333ohm/m based on AWG standard, maybe we ignore this very little resistance.
    When 500v surge is applied with 2ohm, peak current will still be about 250A not about 125A. I think so, right? Thanks for your support!

    en.wikipedia.org/.../American_wire_gauge
    practically the cable impedance will be about 1ohm or 2 ohms (1 meter cable)???