SN74AHCT1G125: ΔIcc

Kuramochi Tadahiko

Guru 28715 points

Part Number: SN74AHCT1G125

Hi,

My customer is considering using SN74AHCT1G125.

ΔIcc is specified as below;

Does it mean that Icc is maximum when input voltage is around 3.4V?

Best Regards,

Kuramochi

over 3 years ago

0 Clemens Ladisch over 3 years ago

Guru 286180 points

The current is even larger at lower voltages. The specification is for 3.4 V because that is the high-level TTL voltage. (And the typical ∆I_CC at 3.4 V, shown below, is zero.)

0 Kuramochi Tadahiko over 3 years ago in reply to Clemens Ladisch

Guru 28715 points

ΔIcc is speciffied 1.5mA(max) @Vi=3.4V.

Is this figure correct?

0 Clemens Ladisch over 3 years ago in reply to Kuramochi Tadahiko

Guru 286180 points

That is the worst-case value at the most extreme temperatures.

This device is designed for TTL signals, so a typical value above zero would not make sense.

0 Emrys Maier over 3 years ago in reply to Clemens Ladisch

TI__Guru* 96862 points

Hi Tadahiko-san,

I see that you're rejecting Clemens answer, even though it's correct and well explained.

Is there something else I can do to help you out?

0 Kuramochi Tadahiko over 3 years ago in reply to Emrys Maier

Guru 28715 points

Hi Emrys-san,

Thank you for your support.

I have an additional question.

Is the vertical axis of the upper Clemens-san's gragh linear scale or log scale?

Best Regards,

Kuramochi

0 Clemens Ladisch over 3 years ago in reply to Kuramochi Tadahiko

Guru 286180 points

The graph above is from SCAA034. The graph below is from SCLA013.

0 Kuramochi Tadahiko over 3 years ago in reply to Clemens Ladisch

Guru 28715 points

Were these graphs measured on different conditions?

The peak values are the same almost on the upper graph, different on the lower graph.

Is the vertical axis of the upper graph linear scale or log scale?

0 Emrys Maier over 3 years ago in reply to Kuramochi Tadahiko

TI__Guru* 96862 points

Hi Tadahiko-san,

Both of the images Clemens provided were produce over 19 years ago. I'm afraid I don't know how the engineer who produced them did the tests precisely.

It's not uncommon to see fairly large variation in the peak supply current when sweeping input voltage -- we don't specify this in the datasheet or guarantee it. All we can guarantee is what's in the EC table of the datasheet for min/max limits.

The key item to take away is that current can exceed several milliamps and you shouldn't hold the input close to the threshold.

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SN74AHCT1G125: ΔIcc