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SN74LVC374A: VOH / VOL specification of SN74LVC374A

ttd
Mastermind 7670 points
Part Number: SN74LVC374A

Dear Technical Support Team,

Do you have the graph of VOH and VOL below?

1.)  VOLmax vs IOL

2.)  VOHmin vs IOL

3.)  VOLmax and VOHmin  at Vcc = 3.3.   If you have any measurement data of them , could you share it?

      Datasheet shows only VOH and VOL of 3V.

Best Regards,

ttd

  • 0
    TI__Guru* 96591 points
    Hi ttd,
    I don't have data to show on VOH/VOL, but I can tell you a very easy way to calculate the worst-case VOH/VOL at any voltage and current that you like. The 'curves' you are looking for are actually straight lines based on ohm's law.

    First, select the appropriate voltage range. For this case, you want 3.3V, so the correct range is 3V. Next, choose the closest current. I'm going to use 24mA since that's the "worst case" presented in the datasheet.

    You can calculate the driver's output resistance at 3V operation (aka r_on of the output mosfet):
    r_onp = (V_cc - V_oh)/I_oh = (3 - 2.2)/0.032 = 25 ohms
    r_onn = V_ol/I_ol = 0.55/0.032 = 17.2 ohms

    Using these values, you can plot the V_oh vs I_oh for V_cc = 3.3V quite easily:
    V_oh = 3.3 - I_oh*25
    V_ol = I_ol*17.2

    Note that these values only hold true for currents less than the absolute maximum listed in the datasheet (50mA), and when you get really close to V_cc (for V_oh) or gnd (for V_ol) we can only guarantee the datasheet spec at 100uA. Also, the calculated values will be the _worst case limit_ across temperature and process variations.