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Original question:

SN74LS244: What does the 'E4' at the end of the part number mean?

SN74LS244: Absolute Minus Maximum Ratings

Liu Yang
Expert 6005 points
Part Number: SN74LS244

Hi Team,

Please help me answer the follow question from my customer, thank you so much.

About maximum rating of input voltage(VI), MAX is with 7V, but what minus voltage can be applied to?

I mean how many minus voltage can be applied to the input pin but wouldn't damage the device?

Best Regards,

Tom.Liu

  • 0
    Guru 279000 points

    The inputs of LS family devices have a diode from GND to the pin:

          

    When the input voltage is negative, a current flows through it:

    In practice, the limit is not the voltage, but the current; your circuit is responsible for limiting the current to a safe value.

    The specification of VIK in the Electrical Characteristics section uses a current of 18 mA, which implies that larger values are probably not allowed.