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Current output capability of SN*4LVC541A

Charles Robidart
Prodigy 155 points

SN*4LVC541A Octal Buffers/Drivers. I wish to use this chip to drive a low impedance with a 25 MHz square wave. If I parallel 4 gates together on input and output to try and gain as much current drive as possible, how much current can I get. e.g. If I wanted to drive 50 ohms to a full 3.3V output I would need 66 mA. If I wanted to drive 10 ohms I would need 330 mA. I suspect the first is acceptable and the second case is not. From the data sheet it appears that under absolute maximum ratings I could get 50 mA from one gate, and a maximum of 100 mA paralleling gates given the maximum Vcc and ground currents. Is this the correct interpretation of the specification? Thanks, Charles Robidart.

  • 0
    TI__Mastermind 36085 points
    Hello,

    I am moving the post to the appropriate forum.

    Regards,
    Diego.
  • 0 in reply to Diego Cortes
    TI__Guru 62050 points
    Hi Charles ,

    your interpretation of the datasheet is right . Exceeding current and voltage ranges on the abs max table could cause device to malfunction and /or reliability issues in the long run .
    current capability increasing would be done in the same way as you described , be sure to tie all the inputs together and all the outputs together to avoid potential issues .
  • 0 in reply to ShreyasRao
    Prodigy 155 points
    Thank you for your response. Charles
  • 0 in reply to Charles Robidart
    TI__Guru* 97046 points

    Charles,

    You should note that the 50 mA on the absolute max table is not dictated by the maximum drive current - it is actually the maximum current that the ESD protection diodes can handle under overvoltage/undervoltage conditions (ie the current must be limited to 50mA or damage will occur).

    If you look into the electrical characteristics table, you can see that the output high voltage (VOH) drops to 2.2V at 24mA of drive.  I doubt it could output much more than that, but I haven't tested the part to 50mA.

    Can you tell us a bit more about your application?  What are you driving that requires such a high current?  I might have some suggestions on other options.