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CSD17483F4: What is the minimum rating for Vgs

Chuchen Wang
Expert 3470 points
Part Number: CSD17483F4
Other Parts Discussed in Thread: CSD17382F4

Hi,

My customer has the following question:

What is the minimum rating for Vgs? I know the datasheet says max is 12V, but how far below the source voltage can the gate go before there is damage? Many datasheets specify Vgs as a range, but I did not see a lower limit specified in this datasheet. We suspect we are damaging the FET with a Vgs of -1.2V, but are not sure since the datasheet does not specify.

Thanks,

Chuchen

What is the minimum rating for Vgs? I know the datasheet says max is 12V, but how far below the source voltage can the gate go before there is damage? Many datasheets specify Vgs as a range, but I did not see a lower limit specified in this datasheet. We suspect we are damaging the FET with a Vgs of -1.2V, but are not sure since the datasheet does not specify.

 

  • 0
    TI__Expert 6985 points
    Chuchen,

    Thanks for the question and considering our devices.
    12V is the maximum voltage you can place on the gate of the device, anything above this and you will start to damage the gate.
    As for lowest voltage we guarantee a MOSFET resistance, this is on page 3 of the datasheet in section 5.1, this is 1.8Vgs. Operating at 1.2Vgs will not damage the gate but there is no guarantee of the performance level. If you look at Fig7 in the datasheet you can see even at 1.8Vgs the resistance vs Vgs curve is extremely steep , at 1.2V it will be virtually vertical and heading to infinite resistance. Extremely small variations in device threshold (normal with lot to lot and process variations) have huge influence on the resistance and as such we are not able to guarantee any type of resistance performance @ 1.2Vgs.
  • 0 in reply to Chris Bull
    Prodigy 20 points

    Hello, I think the question was misunderstood. We have an application that may apply a negative Vgs to the gate of the FET. I would like to know what the voltage is where the gate and FET would sustain damage. We don't need it to conduct at these low Vgs voltages; just not be damaged. Thanks.

  • 0 in reply to Clifton Lin
    TI__Expert 6985 points
    Clifton,

    OK, now I understand the question.
    This device has a single ended Gate ESD protection diode between the gate and source if you put a negative voltage on the gate this diode from gate to source will forward bias and turn on. In the datasheet there is a specification for the maximum current allowed through this gate diode which is 35mA. If this is exceeded the device will be damaged.
    An alternative would be to use the CSD17382F4, this is pin to pin , 30V, lower resistance and has back to back ESD diode protection, the penalty with this device (as with any back to back ESD gate protection on FETs) is much higher gate leakage but you can place a -ve gate drive current of -1.2Vgs on the device no problem. Leakage will be <5uA.