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LM76005: LM76005 and ISO 7637-2

Dirk Bender
Prodigy 90 points
Part Number: LM76005

Tool/software:

Hello TI Team,

I am planning to use the LM76005 in an automotive design.
The end device can work as a 12 V or 24 V system and the load dump is already limited to a maximum of 58 volts with a diode in the vehicle.

In my opinion, the LM76005 should already be able to handle the requirements of ISO 16750. However, further modifications are needed to fulfil the requirements of ISO 7637-2.

The regulator may operate up to a maximum of 65V at the input. The vehicle's clamping diode clamps to a maximum of 58 volts. In order to be able to catch the bursts of ISO 7637-2, I would need a diode that only opens at greater than 58V and clamps at less than 65 volts. So far I have not been able to find one.

Does TI have any recommendations for this usecase?

Is another TI switching regulator perhaps more suitable?

Kind regards
Dirk

  • 0
    TI__Guru 58171 points

    Hello Dirk 

    LM76005's maximum input voltage is 60V (not 65V) and the Abs max of the SW node is 65V.  The device might be permanently damaged if the SW node voltage exceeds 65V (due to a switching) during the load dump. 

    -EL

  • 0 in reply to EricLee
    Prodigy 90 points

    Hallo,

    thank you for your answer. Did you have a simple solution for my usecase or is it only possible to use the LM76005 with a surge stopper to fulfil the ISO 7637-2?

    Dirk

  • 0 in reply to Dirk Bender
    TI__Guru 58171 points

    Hello Dirk 

    It is trickly because the minimum clamping voltage should be greater than 58V and the maximum clamping voltage should be less than 60V.  

    • The regulator may operate up to a maximum of 65V at the input. ==> Please confirm if this is a mandatory requirement. 
    • I would need a diode that only opens at greater than 58V and clamps at less than 65 volts ==> Please confirm the LM76005 should be enabled when the input voltage is greater than the 58V but less than 65V. 

    -EL 

  • 0 in reply to EricLee
    Prodigy 90 points

    Hello,

    • The regulator may operate up to a maximum of 65V at the input. ==> Please confirm if this is a mandatory requirement. 
      • Since the transients of ISO 7637-2 can also occur during operation, the controller should also work when the faults occur.
    • I would need a diode that only opens at greater than 58V and clamps at less than 65 volts ==> Please confirm the LM76005 should be enabled when the input voltage is greater than the 58V but less than 65V. 
      • Since the transients of ISO 7637-2 can also occur during operation, the controller should also work when the faults occur.

    I think these two Points of the ISO are relevant for this because the load dump only generat a max peak with 58 Volt.

    - ISO 7637-2:2011 Pulse 2a positive peak 112 Volt (0,05 ms)

    - ISO 7637-2:2011 Pulse 3b positive Spike 150V to 300 V (150ns)

    Do you have a solution for this?

  • 0 in reply to Dirk Bender
    TI__Guru 58171 points

    Hello Dirk 

    The new device will be released in two week. Sorry, I cannot disclose the details of pre RTM'ed device in public E2E.

    -EL

  • 0 in reply to EricLee
    TI__Expert 8249 points

    Thanks Eric, I will provide the information via email and will continue the discussion there.

    Best regards

  • +1 in reply to franziskus
    TI__Guru 58171 points

    Thanks for promoting SR-WVB devices. Please feel free to contact me if you have any questions.
    -EL