74lvc14A current sink exceeding recommended max, but below absolute maximum

Jorge Rive

Even though the recommended max sink current for the 74LVC14a is 24mA, can I sink more as long as I stay below the 50mA absolute max without damaging or degrading the IC? I need to sink about 40mA, periodically, for about 2 seconds of a 10sec cycle (20% duty cycle). I do not have the room to "double up" on devices to put 2 in parallel to achieve greater sinking capacity. I suspect the only issue in using the single device to sink more than the recommended current is that the guaranteed max. VOL will be greater than the 0.55V specified, but no damage will be caused to the device. In fact, based on the max output impedance specified at 24mA and 0.55V, the max Vol will be about 0.9V. Can do this without overstressing the device? Thank you, Jorge

over 14 years ago

0 Chris Cockrill over 14 years ago

TI__Mastermind 46480 points

We do not Test beyond the recomended IOH and IOL. So we dont know what happens beyond the recomended. The Voh and Vol may drop in a linear fashion or the part may reach a point and just quit.

In this case I happen to have some data IOH IOL /Voh Vol.

The part should not be damaged if you dont go over the abs max. but we dont guarrantee functionality beyond the recomended max.

Here is some data that should help with your decision.

Vol Vol.xls

0 Jorge Rive over 14 years ago in reply to Chris Cockrill

Prodigy 80 points

Hi Chris, thank you for your response and attached data. The data indicates VOH and VOL "bad" in the last two columns. However, when i plot the data, VOL in particular is right "on top" of the VOL good data. What does VOL-bad refer to? Was this data from a failing device?

Thanks again!

0 Chris Cockrill over 14 years ago in reply to Jorge Rive

TI__Mastermind 46480 points

You can ignore that. Both are in spec. The charts just shows some process variation. We were looking at some parts where a customer was having problems with a production lot of material. They had their Vih in the threshold region and one lot did not work due to typical process shift. Both parts were well within spec.

0 Jorge Rive over 14 years ago in reply to Chris Cockrill

Prodigy 80 points

Thank you, Chris.

Regards.

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74lvc14A current sink exceeding recommended max, but below absolute maximum