Posted Aug 4, 2011, by Patrick Carrier
Whether you are trying to correlate simulated waveforms to measured waveforms for a DDR3 signal, or board timing numbers for a simple SDRAM bus, or measured Z-parameters when looking at a PDN impedance, or even just a simple trace impedance measurement on the TDR, it all begins with the proper stackup. I explore some of the commonly overlooked nuances of stackup modeling in my recent article in InCompliance … Read More
Tags:
dielectric,
HyperLynx,
correlation,
measurement,
measurement correlation
Posted Aug 3, 2011, by Patrick Carrier
Yes, you should care about the fact that PCB traces, when actually manufactured, end up having more of a trapezoidal shape. This is especially true when modeling those traces to determine the correct impedance. More important than the trapezoid shape itself is the resulting change in trace width. Typically, on 1/2-oz. copper, the etching process leaves the top of a trace about 0.5 mils narrower than … Read More
Tags:
HyperLynx,
impedance,
correlation,
trapezoidal traces,
measurement,
stackup
Posted Aug 2, 2011, by Patrick Carrier
Simulations should match measurements. Otherwise, what good are they? When doing signal integrity simulations, that starts with comprehensive stackup modeling. I quite often hear that stackup editor calculations don’t match measurements, but when I probe deeper, I usually find that the stackup has not been modeled properly. More often than not, the calculated impedance ends up being much lower … Read More
Tags:
stackup,
dielectric,
dielectric constant,
correlation,
measurement,
HyperLynx,
impedance
