Greetings All,

I am using the PADs HyperLynx v9.4.1 to run a RLC repot for a board I am working on. The report states that on one trace I has a total inductance of 6.9nH. However, using a third party calculator (same variables) I am getting a total inductance on the same traces as 25.08nH.

The formula for this calculator uses is as follows:

Lms = 0.00508L[ ln (2L/(W+H) + 0.5 + 0.2235*((W+H)/L)]

Lms = Inductance of microstrip in microhenreis

W = width of strip (inches)

L = length of strip (inches)

H = distance between the strip and the ground plane

What formula does HyperLynx use to calculate the inductance on the RLC report?

I’m trying to figure out why there is such a large discrepancy.

Any advice would be greatly appreciated.

Thanks,

Tony

Tony,

HyperLynx SI used a 2D field solver instead of an equation. Equations are handy for some cases but have a range of input values that are valid. If you use the equation with input values outside the assumed range then the output diverges from the correct answer. See if you can find the assumed input range for your equation and double-check the length units (H variable) that are expected for that equation.

Regards,

Weston