Issue link: https://iconnect007.uberflip.com/i/1276973
40 DESIGN007 MAGAZINE I AUGUST 2020 entry there, the tool will automatically add a 1-mOhm value (but this automatically-added value does not show up in the series resistance input field). This explains the low-frequency value in Figure 2 since we have four series inductors, each will have 1-mOhm series resis- tance by default. If we explicitly call out zero for the series resistance parasitics on all inductors, we get Figure 8. Now, the low-frequency value starts at the correct 1.3-mOhm value, but we can also notice that the first two peaks get a little bigger. This is happening because we removed the extra series resistances, which helped to lower the antiresonance peaks. Note that with the circuit values used in this example, explic- itly calling out zero body capacitance for the inductors will not change the result. This is eventually what we expect: a smooth impedance profile, no unexpected and unex- plained sharp resonances, and asymptotic low-frequency impedance matches the sum of series resistance values. We are almost done, but it still would be useful to check the capacitor's equivalent cir- cuit one more time and take another look at Figure 7: Parasitic definitions of the Lsrc inductor. Figure 8: Impedance magnitude and phase of the simple PDN showed in Figure 1, with forcing zero body capacitance of capacitors and zero series resistance of inductors.