|MadSci Network: Physics|
Another good question, Dilan! The constant K generally applies for a digital circuit, such as a microprocessor. It is a function of the exact transistor size and how the wafer was processed. But the power dissipation of a uP also depends on the state of its input and output lines, and so the constant K is rarely defined in a manufacturer's data sheet. If a manufacturer were to do so he would possibly be giving away his own trade secret information. Also, please remember that the formula is just a rough rule of thumb. And for analog integrated circuits the formula does not apply. While I don't know of any further information to give you, you can almost certainly measure the constant K for a given circuit. Take, for example, a simple CMOS chip (such as a NAND gate) and set the experimental rig up to measure the power drawn by the chip. Then drive one of the inputs with a variable frequency source while measuring the chip power. As you increase the frequency, the power drawn will go up. Plot power vs. frequency and the slope of the line will give you K (for that chip only). I hope this helps!
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