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Total Current Requirement for Octal Buffers (SN74LVCH244APWRG4)

vijetha hn
Expert 1230 points

Hello,

I am using an Octal Buffer  in my design. Part number : SN74LVCH244APWRG4.\

I am calculating the current requirement of the IC as (no. of used O/P pins*IOH)+(ICC). This will be (8*24mA+10uA) 192.01mA. 

But it is mentioned in the Datasheet that Continuous current through VCC or GND is 100mA.

Please clarify whether this is the right method of calculating the current requirement for the buffers? If yes, how the IC can withstand the current of 190mA when the absolute maximum value of continuous current requirement is 100mA? If NO, what is the exact method of calculating the current requirement for the Buffers?

Regards,

Vijetha HN

  • 0
    TI__Genius 14485 points

    Vijetha,

    Good question. This can be confusing.

    The maximum current through a single output can be 50 mA maximum. However, if you are using more than one output, the sum of the output currents should be no more than 100 mA. The total current the part can handle is limited by the temperature of the silicon junctions due to I^2*R heating. If all outputs are operated continuously at 50 mA, then the part will burn up. However, the part would be able to supply 50 mA on each of two outputs.

    With that said, it's important to note that the parameters in the absolute maximum section guarantee that the part will not fail if operated at those levels. It is best practice to design below the absolute maximum levels. The recommended operating conditions section provides parameters for designs so the part works within the specifications.

    For your application, you need a part with higher drive. If you tell me more about your system an operating conditions, I can help recommend a part for you.

    James