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SN74LVC2G02: 74LVC2G02

Jani Isoo
Intellectual 1910 points
Part Number: SN74LVC2G02

Hi,

The 74LVC2G02 part has a recommended supply voltage of 1.65V to 5.5V. Do you have any data for the supply current requirements over this supply range? For example, if the function of the gate did not change but the supply rail was varied over 1.65V to 5.5V, then how would the supply current change? Are there any graphs of this characteristic available?

 

Is this part “optimized” for 3V3 operation?

thanks,

Jani

  • 0
    TI__Guru* 96712 points
    Hi Jani,
    Yes, the LVC family was designed specifically for 3.3V operation, and the extended range was added because it operates well over that voltage range.

    No, we do not have typical supply current data over voltage. The typical static supply current for an LVCxG device is on the order of 300nA.
  • 0 in reply to Emrys Maier
    TI__Intellectual 1910 points
    Hi Emrys,
    Customer has the LVC NOR gate configured as an LC oscillator running at just under 1MHz, and noticed that the current taken from the supply increases significantly between 4V and 5.5V. When the gate is operated at 3.3V, the supply current taken is comparable to a 74HC02 device (less than 2mA).
    Do you have some explanation?

    Thanks,
    Jani
  • 0 in reply to Jani Isoo
    TI__Guru* 96712 points

    Hi Jani,

    Yes, this is expected behavior from CMOS devices. The SN74LVC2G02 is specified to operate with the inputs at a static value of Vcc or GND (which is where the 300nA of static current is measured), but in an oscillator, the input is generally held somewhere between these two values.

    It's likely that their oscillator circuit uses slow edges (ie RC circuits) to provide delay and thus oscillation.  Slow edges into CMOS devices produce large amounts of shoot-through current.

    We have an application report on this phenomenon because it is such a common topic.

    Implications of Slow or Floating CMOS Inputs

    I have a simplified input diagram that shows how the current flows here:

    Note that Mp and Mn will both be turned "on" if the input is below Vcc - Vtp and above Vtn.