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SN74LVTH16245A-EP: Power Dissipation

Joyce Chiu
Prodigy 10 points
Part Number: SN74LVTH16245A-EP

Hi

I'm trying to calculate the power dissipation for SN74LVTH16245A-EP. I used the equation from the document SCAA029 page 18.

I am having difficulty to figure out the Slop of the I_CC vs frequency curve (I_CCD).


I found 2 plots, and both of them are Icc vs freq for LVT. However, their value doesn't line up. Left plot starts from about 25 mA at 0 MHz, and right plot at about 4 mA at 0 MHz. Why are they different? Which one is correct?

Left plot is from the document SCAA029 page 15. Right plot is from the document SCEA002A page 8.

  

Also, the slop of the right plot doesn't seems right to me. I tried to obtain points from the graph, and plot it in the Excel to get the slope. The slope seems to be closer to about 0.88 instead of 0.11. Could you explain how the 0.11 was obtained?

Reference documents:

SCAA029: https://www.ti.com/lit/an/scaa029/scaa029.pdf

SCEA002A: https://www.ti.com/lit/an/scea002a/scea002a.pdf 

Thank you.

  • +1
    TI__Mastermind 26010 points

    Hi Joyce,

    I can't really say how the author got 0.11 instead of 0.88 since I don't have his calculations or any details about how he conducted his test. I'd note that the document (both documents) was written 25 years ago. 

    The graph on the left seems more comprehensive but it's hard to say without details. I'd run the calculations with both graphs and use that as an estimate. Otherwise the only way you're going to get an accurate number is to buy the part and measure the power dissipation.

    Best,

    Malcolm