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SN74LVC1G373: outputs shorted to ground

Prodigy 310 points

Replies: 1

Views: 26

Part Number: SN74LVC1G373

Hi team, working with a customer on this device. The datasheet wasn't clear to answer the following:

1. Would the outputs be damaged by a short to ground?

2. And what would the current be limited to?

  • Hi Kannan,

    To answer your second question first, there is no current limiter in this device. The current is limited by ohm's law.

    As for 'would there be damage' -- yes, almost certainly. Sometimes devices survive this sort of incident, however it is best to replace the device to be safe. Even if the device does survive, there's no telling how much reliability has been affected.

    For a more detailed explanation:

    From the absolute maximum ratings table, we can learn the maximum limits of the device:

    The output maximum current is 50 mA -- in other words, if you drive more than 50 mA at the output of the device, it is very likely to be immediately damaged. If the output is shorted to ground (let's guess at 1 ohm) and the output is in the 'high' state (3.3V, as a guess), then the expected current is: I = V/R = 3.3/1 = 3.3 amps of current, and would certainly exceed the 50 mA limit.

    Of course, I'm making this excessively simple (which is typically enough for a quick analysis with logic) -- our device does have some output resistance. For an LVC family device, that's typically around 10 to 15 ohms. Using 10 ohms, we get 3.3/10 = 330mA -- again, well in excess of the maximum rating of the device.

    Looking for a low voltage translator? Check out the AXC family that supports 0.7V to 3.3V translation!

    The Logic Minute training page has videos on many interesting topics that all are kept shorter than 5 minutes.