Spiral Inductor formula

[Olly]

Hi Carl, I'm having difficulty with the spiral inductor formula on page 551 and think there may be an error somewhere.

Shouldn't average diameter = 0.5(dout+din) ?

Also, what is the variable 'r' referring to in the '2.8r' term?

Regards

[Carl-NC]

Correct, d_ave should be 0.5(d_out+d_in). Also, the 'r' should not be in the equation. I've added this to the errata, thanks.

[Olly]

Thanks Carl, thought I was going nuts....