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SN74LVC1G14

Other Parts Discussed in Thread: SN74LVC1G14, SN74LVC1G17-EP, SN74LVC1G17

My customer has the following questions on the LVC1G14:

I need to know about the partial power down capabilities of the SN74LVC1G14 device.

Can you drive the input with let’s say 3.3v while the VCC is turned off or is there an ESD diode in the input clamping the voltage to the power rail?

Thanks

  • Saeb,

    When Vcc = 0V the input(Vi = 0 to 5.5V) and output(Vo = 0 to 5.5V) of the device are high impedance, so it can't be driven by the 3.3V input. This is what the partial power down/Ioff setting does, it isolates the device from the rest of the circuit. This device does not have clamp diodes to Vcc, only to GND. The exact parameters can be seen in the data sheet, Ioff - Electrical Characteristics, I/O Clamps - Absolute Maximum Ratings.

    Regards,

    Robert Regojo.

  • Hi,

    Does this mean that you cannot apply more than 5.5V at the input even if the input current is limited by series resistor to less than 50mA?

    Regards,
    Santhosha RK
  • Hi,

    I have similar problem as that of Santhosha RK for the part SN74LVC1G17-EP.

    Cheers,
    Pradeep
  • Hey All,

    The absolute max rating of the device for input voltage for both devices listed is 6.5 Volts. Anything above this will void the warranty on the devices.

    Thanks,
    Daniel
  • Hi Daniel,

    Thanks for the reply.

    I have tested SN74LVC1G17 device with input greater than 6.5V with a current limiting resistor.

    I have observed that the input voltage is clamping around 8V . I have applied input voltage 32V with 1K ohms series resistor.

    and I have observed the device is working as expected.


    Cheers,
    pradeep
  • Hi Pradeep,

    The device may work above 6.5 Volts with current limiting resistors however once the device goes above the Absolute Max voltage you void the warranty on the device and we cannot guarantee any of our specs on the data sheet.

    Can you go above 6.5V? Probably. Whether or not you should is a different question. If you are fine voiding the warranty and potentially damaging the device in the long run than you can, but it is highly not suggested. The device may work in the short term, but you risk damaging parts of the device in the long run and putting the device out of spec.

    Thanks,
    Daniel