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TVS2701: ESD Protection for revers polarity PMOS

d_zero
Genius 4795 points
Part Number: TVS2701
Other Parts Discussed in Thread: TVS2201, STRIKE

Hi Team,

we are currently using the following scheme for reverse polarity where TVS is after RPP.

The input is 24VDC from standard industrial supply.

But now we want to ESD protect also the PMOS.

Would you recommend the following approach:

1)

 

2)

Questions:

a) Would you recommend a TVS2701 or TVS2201 for 24V system?

b) Do you can provide the clamping voltage Vc for 10/1000 pulse? The Ds only has Vc=35.7V for 8/20 pulse and probably the 10/1000 Vc is lower correct ?

c) The clamping voltage of TVS2701 is Vc=35.7V and the Vds of the PMOS is 30V is this a problem when there is an ESD event ? Should the rating of PMOS Vds be grater than clamping voltage?

d)  In case when RPP is on , GND_IN= 24V, 24VDC=0V will the TVS2701 survive ?

e) Regarding the protection of the gate ( vgs 20V) , should we use the zener or the TVS the bidirectional Zener or TVS version also?

f)

Our system when normal working 24VDC, we should ESD protect the PMOS with input bidirectional TVS and gate protection either Zener or TVS.

Our system when in RPP mode , Although our system will not operate in reverse polarity conditions, it should not be damaged as it will be protected by our RPP circuit.

And we have an indicator when in RPP mode

Best Regards,

d.

  • 0
    TI__Mastermind 18220 points

    Hi d_zero,

    a. I would recommend TVS2701 

    b. Yes the clamping voltage would be lower for 10/1000uS, unfortunately we don't have the data for this spec. 

    c. The clamping voltage will be dependent on the ESD/Surge event. The TVS2701 has a typical clamping voltage of 34 V at a peak surge current of 24 A (8/20uS). Are you expecting surge currents near 24 A?  

    d. Yes the device will survive, any DC voltage at or below the working voltage, (27 V), will not cause the diode to conduct large significant current. 

    e. I would recommend using the Zener here to clamp the voltage below 20 V.

    Regards,

    Sebastian 

  • 0 in reply to Sebastian Muriel
    Genius 4795 points

    Hi Sebastian,

    thank you for the input.

    Regarding c) do you have a dependence graph of clamping voltage Vs peak surge current for TVS2701?

    So if we expect this during ESD testing  should then the PMOS VDs be rated more than Vc clamping voltage?

    Best Regards,

    .

  • 0 in reply to d_zero
    TI__Mastermind 18220 points

    Hi d_zero,

    The clamping voltage is measured by injecting a 8/20µs pulse at certain peak surge current. For this device we only have the clamping response for an 8/20µs surge pulse with peak surge current of 27 A. 

    If you were expecting a surge current of 24 A then yes you would want a higher VDs rating for the PMOS. However, you mention you expect this during "ESD testing". ESD and Surge are two different types of transients, this graph will give you the clamping response for a surge event but not an ESD event.

    Are you more concerned with protecting from ESD events? The clamping voltage for an ESD strike could be lower depending on the ESD voltage (kV). 

    For more details on ESD please see our ESD Fundamentals Training.

    For more details on Surge please see our Demystifying Surge Protection Training. 

    We have the ESD1LIN24 which is a 24 V (Vrwm) diode that has the clamping voltage specified for ESD strikes up to ~14kV. It offers up to 30kV ESD protection. 

    Regards,

    Sebastian 

  • 0 in reply to Sebastian Muriel
    Genius 4795 points

    Hi Sebastian,

    if we want test against IEC 61000-4-5 industrial surge.

    The TVS2701 is valid and will protect following Classes marked in green is that correct? 

    TVS2701 can support up to 27A for the 8/20us pulse.

    And in our case the RPP PMOS is on a DC power IN (24V max 2.5A), Is this case can we use R=42Ohm or do we need R=12Ohm ?

    Best Regards,

    d.

  • +1 in reply to d_zero
    TI__Mastermind 18220 points

    Hi d,

    Is the PMOS connected to an AC/DC converter? If so, you would use the 42 Ohm network.

    DC ports that are connected to an AC/DC power converter are not regarded as low voltage power supply ports where you would use a 12 Ohm coupling network. 

    Regards,

    Sebastian