• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Subscribers 33 subscribers
  • Views 441 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TIOL1123: Surge Test Setup - generator source impedance

Jonathan Plenske
Prodigy 50 points
Part Number: TIOL1123

Hello,

regarding to the datasheet page 19, TIOL1123 is capable of withstanding up to 1.2 kV of 1.2/50 – 8/20 μs IEC 61000-4-5
surge with a source impedance of 500 Ω.

IEC61000-4-5 states to use  2, 12 or 42 Ω as source impedance.

Is there any specific reason why the 500 Ω are used?

Thanks & regards,

Jonathan

  • 0
    TI__Mastermind 33330 points

    Hello Jonathan,

    The 500 Ω is not referring to the internal source impedance of the generator, but instead it is referring to an external 500 Ω series resistor placed between the generator and the TIOL1123's pin. 

    Regards,

    Jonathan

  • 0 in reply to Jonathan Nerger
    Prodigy 50 points

    Hi Jonathan,

    thanks for pointing that out. I missed that information.

    The description in the datasheet is kind of misleading then:

    So is it recommended to use external protection with TVS diodes in any case?

    Otherways, without the 500R series resistor, there is no chance to match the IEC requirements i guess.

    Is the internal surge protection only applicable with that 500R then?

    Thanks & regards,

    Jonathan

  • +1 in reply to Jonathan Plenske
    TI__Mastermind 33330 points

    Hi Jonathan,

    This modified version of IEC 61000-4-5 with this higher series resistance was a common requirement we saw among factory automation customers.  The small sensor applications typically used with the TIOL1123 are typically lower current and can't handle the higher current requirements of the standard surge requirements.

    The TIOl1123 has integrated ESD protection diodes, but it does not have an integrated surge protection diode.  Therefore the surge current reaching the TIOL1123 must be limited to 2A max, or an external diode would be required. 

    The TIOL1123 will pass a ±1.2 kV,1.2/50 μs IEC 61000-4-5 surge with a source impedance of 500 Ω.  With a lower source impedance such as 40 Ω, you would need an additional protection diode.

    Regards,

    Jonathan

  • 0 in reply to Jonathan Nerger
    Prodigy 50 points

    Got it, thanks for clarifying!

    Best regards,

    Jonathan