Troubleshooting Distributed Power Systems: Measuring Impedance Using VNAs (2-Port) (Part 4 of the on
Shunt through, wideband measurements can be made from approximately 100 microohms to a few ohms. This is the measurement performed by designers for the power distribution network (PDN) assessment of VRMs and POLs. This technique may also be used to measure the impedances of batteries, dc-dc converters, EMI filters, and other functions. Setup requirements such as 4-wire connections, a common-mode transformer, dc blockers, and ac versus dc coupling are explained in this video. Also discussed is the use of a preamp to measure impedances below 1 milliohm. In addition, the video presents impedance measurement examples such as a POL’s output, a motherboard’s PDN and a 250-microohm resistor.