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LM74701-Q1: Negative Surge

Part Number: LM74701-Q1
Other Parts Discussed in Thread: LM74700-Q1

Hi team,

I have a question.

Can this device withstand for negative 600 volts? If not, what could be the right device for this?

Best Regards,

Shoji

  • Hi Shoji,

    Where is the -600V coming from ? Is it an automotive test pulse ? If yes, share the pulse waveform and source impedance details.

  • Hi Praveen,

    Yes, this is an automotive test pulse. OEM requires this value. I'm asking them to tell me the detailed profile, but not yet. This negative surge is a field decay. To meet requirement, they use big reverse voltage diode, but the V_f is too big to use our proposal. For the load dumping, the customer uses Zener diode. This positive surge is not so big than the field decay surge. To reduce the voltage drop(0.99V), I'm looking for any ideal diode controller.

    Is there any controller which contains TVS for clamping both surge? If yes, that'll be work even under -600V condition.

    Best Regards,

    Shoji

  • Could you move this thread to internal forum if you want to know more specific information?

  • Hi Yuya Shoji,

    This test is probably ISO 7637-2  Pulse 1 for 24V battery. 

    LM74701-Q1 is suitable for 12V ISO Pulse-1 which is only upto -150V and not suitable for 24V ISO Pulse-1 which can go as high as 600V.

    For this application, you can consider using LM74700-Q1 with 2 uni-directional TVS in back-to-back configuration as shown below. Please refer to section '10.1.1.4 Selection of TVS Diodes and MOSFET for 24-V Battery Protection Applications' of LM74700-Q1 datasheet for more information.  

  • Hi Praveen,

    Thank you for your proposal!

    Best Regards,

    Shoji