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SN74LVC1G08: How about the Absolute Maximum input clamp current when Vin>6.5V

John11513
Expert 5720 points
Part Number: SN74LVC1G08

Hi team,

The datasheet of this device only specify the maximum input clamp current when Vin<0, however, no data for Vin>6.5V. My customer needs this data for input protection design. In their design, the input of LVC1G08 has to be unavoidably facing an continuous over voltage condition as high as 12V. 

Thank you,

John

  • 0
    Guru 316690 points

    LVC devices have overvoltage-tolerant inputs without an ESD protection diode to VCC, i.e., high voltages are not clamped. This implies that when the voltage becomes too high, the gate isolation breaks down. This immediately damages the device; there is no safe current level.

    So it is not possible to design a protection circuit that simply tries to limit the current.

    Dropping the voltage to a safe level requires a circuit that shunts some current to ground, e.g., a resistor voltage divider, or resistor + some kind of Zener. But I do not know if voltages smaller than 12 V need to be detected as high, or what currents are allowed.

  • 0 in reply to Clemens Ladisch
    TI__Expert 5720 points
    Thank you for your quickly reply. Seems they have to change design.