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TSM36A: EFT IEC 61000-4-5

d_zero
Genius 4440 points
Part Number: TSM36A
Other Parts Discussed in Thread: ESD1LIN24, ESD751, ESD761

Hi Team,

i want to use TSM36A on my signal trigger input line  ( works from 3.3V to 24V)  for surge protection.

Do i need additional diode for EFT  IEC 61000-4-5 protection? EFT is not specified in TSM36A.

I also looked at ESD1LIN24, ESD761 and ESD751 that work with 24V and non of them has specified EFT protection rating.

Here is my schematic the D16 is for Reverse polarity protection. Can you please comment.

Do i need to consider bidirectional EDS and surge protection because of RPP ?

Best Regards,

d.

  • 0
    TI__Genius 13580 points

    Hi d,

    I'm confident the TSM36A would pass at 80 A for IEC 61000-4-4 EFT we just didn't spec it for this part. Other surge devices in our portfolio such as the TVS devices provide 27-40 A of IEC 61000-4-5 surge protection and they all passed at 80 A IEC 61000-4-4 EFT. 

    The ESD1LIN24, ESD761, ESD751, would provide EFT protection as well but it was not spec'd. Is there a certain level of protection you're looking for? 

    Yes you will want a bi-directional device if you want reverse polarity protection. 

    Regards,

    Sebastian

  • 0 in reply to Sebastian Muriel
    Genius 4440 points

    Hi Sebastian,

    1)

    i want to use TSM36A on a signal line that can work on 24V. For EFT we need to pas test level 3 1kV

    Can this diode handle level 3 ?

    2)

    So for my schematic i have to use 2 TSM36A connected back to back ?

    Br,

    d.

  • 0 in reply to d_zero
    TI__Genius 13580 points

    Hi d,

    1) Yes it should pass level 3.

    2) Actually if you connect pin 1 to GND and pin 2 to the input you will have a bi-directional configuration to provide reverse polarity protection. 

    Regards,

    Sebastian 

  • 0 in reply to Sebastian Muriel
    Genius 4440 points

    Hi Sebastian,

    can you explain second point what do you mean? We use D16 for reverse polarity protection CDSU4148. 

    My question was do i need in this case 2x TSM36A devices connected back-to-back

    Br,

    d.

  • +1 in reply to d_zero
    TI__Genius 13580 points

    Hi d, 

    Apologies I misunderstood; I thought you wanted to use the TSM36A for reverse polarity protection. By the connecting the TSM36A pins as I mentioned you would get a bi-directional diode that would protect from reverse polarity if the TRG_IN and TRG_GND were ever mis wired. You should still consider ESD protection even though you implemented D16 for RPP however.

    What's the maximum signal speed of the data line? TSM36A has pretty high capacitance so it can't handle high speed signals. 

    We have some devices with lower capacitance such as ESD1LIN24 that would work. It should be able to pass level 3 EFT, I've found more devices in our portfolio with low surge ratings such as 3 A (8/20us) that pass EFT at level 4 (80 A). ESD1lIN24 provides up to 4.3 A (8/20us) of surge current protection. 

    Regards,

    Sebastian 

  • 0 in reply to Sebastian Muriel
    Genius 4440 points

    Hi Sebastian,

    the max speed is about 1MHz, i don't think that is a problem?  also if you look at the schematic we have one the signal 1nF ( C180).

    now i connected two TSM36A back do back, is that ok?

    also i choose the TSM36A because it can handle 24A (8/20us) , and the other that you suggested can't do that.

    this signal input is tested against Class2 1kV 24A Req=42Ohm

    Best Regards,

    d.

  • 0 in reply to d_zero
    TI__Genius 13580 points

    Hi d,

    The capacitance might be too high at 50pF (typical) for a 1 Mhz signal, this might cause signal integrity issues. I would conduct testing to see if the trigger signal is still detected since the high capacitance of this device could degrade the signal.
    The PCB layout is also important for determining your capacitance budget. For layout suggestions please see our ESD Layout Guide.

    We have other devices with lower capacitance that can be used but none of them will meet the 24 A Surge current requirement. 

    Regards,

    Sebastian