SN74CBT16245C: How to calculate static and dynamic power consumption?

Aashrith Gangam

Part Number: SN74CBT16245C

Tool/software:

Do I need to consider Icc or Delta Icc for static power?

Which parameters should be used for calculation of dynamic power?

0 Clemens Ladisch over 1 year ago

Guru 317280 points

See the test conditions; you can ignore ΔI_CC.

This device is a passive switch; it is not clear what you mean with "dynamic power". Are you applying a high-frequency signal to the /OE inputs?

For practical purposes, the highes power dissipation comes from the current through the switch (which is not called dynamic because it does not need to change). See [FAQ] How to Calculate the Max Junction Temperature of an Analog Switch/Multiplexer.

0 Aashrith Gangam over 1 year ago in reply to Clemens Ladisch

Thanks for the reply.

Then according to the formula,

Vcc = 5V, Icc = 3uA, n = 16, r_on = 12 Ohm, I_sw = 128 mA.

P = 5*3*10^-6 + 16*(128*10^-3)^2*12

P = 3.145743 W

This seems a little high or where did I go wrong?

0 Aashrith Gangam over 1 year ago in reply to Aashrith Gangam

And should I consider delta icc here?

0 Clemens Ladisch over 1 year ago in reply to Aashrith Gangam

Guru 317280 points

You are not going to send 128 mA through the switch, are you?

0 Nir Gilgur over 1 year ago in reply to Aashrith Gangam

Hello Aashrith,

Using the FAQ Clemens linked, the Max power dissipation is 3.15W.

But this is worst case scenario when you are inputting 128mA into the switch, which I am assuming is not the case in your application.

Thanks,

Nir

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