Ultra-low Impedance Testing Using the 2-Port Shunt-Through Measurement Technique

Measuring ultra-low impedances (20 micro-ohm) is a challenge for any power distribution network (PDN) design engineer. The 2-port shunt-through measurement is the standard method for measuring milliohm impedances up to very high frequencies (GHz). Unfortunately, this measurement includes an undesirable ground loop related to the instrument grounds and test setup cabling. The ground loop introduces significant errors if proper care is not taken. This application note shows how to measure as low as 20 μΩ using the Picotest J2102A as a ground loop breaker.

Continue reading “Ultra-low Impedance Testing Using the 2-Port Shunt-Through Measurement Technique”

Geoffrey Hazelett – Impedance and Polar Instruments Tools

aDuring PCB West, we met with Geoffrey Hazelett to discuss one of the most important PCB topics: impedance. Vice President Sales at Polar Instruments, he also explained the importance of understanding electromagnetic models, solutions of Maxwell’s equations in a two or three-dimensional environment, etc., and shared some insight on PI’s tools.

Continue reading “Geoffrey Hazelett – Impedance and Polar Instruments Tools”

Impedance Discontinuity and Signal Reflection in PCB Transmission Lines

We previously quickly discussed signal reflection in our PCB Transmission Line series. This is an in-depth article about this very important topic that PCB designers should master. The first thing to remember is that reflections in transmission lines occur due to impedance discontinuity.

Continue reading “Impedance Discontinuity and Signal Reflection in PCB Transmission Lines”