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.

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Optimizing Power for Clocks and other Sensitive Applications

Introduction

The topic of clock jitter performance seems to be a current focus of clock, ADC, and power supply manufacturers.  The reasoning is clear; clock jitter interferes with the performance of digital circuits including high speed ADCs.  High speed clocks can be quite sensitive to the “cleanliness” of the power they receive, though quantifying the relationship takes some effort.

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