Impedance

Includes measurement, analysis, and optimisation of impedance across frequency, including input/output impedance, PDN impedance, and techniques such as shunt-through and injection methods.

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How To Verify Control Loop Design

The non-invasive stability assessment is a method that uses an output impedance measurement to accurately determine stability without access to the control loop. The…
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Article
Troubleshooting Distributed Power Systems: Using Current Injectors (Part 5 of the ongoing video series.)

Previous videos in this series discussed the use of vector network analyzers (VNAs) to measure impedance using one- or two-port configurations. This video discusses…
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Video
Five Things Every Engineer Should Know About PDN

We generally associate the Power Distribution Network (“PDN”) with the power circuits used to drive CPUs and FPGAs. The increasing use of FPGAs in…
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Article
Oscilloscope Mistakes: #2 (Part 2 of 4)

Avoiding common pitfalls will get you better data with minimum effort. Steve Sandler takes a look at four common scope mistakes and shows how…
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Article
FAQ #30: Can the Bode 100 measure complex permeability of Inductors/Chokes with some additional adapter and/or equipment?

It can measure impedance and that can get you there. We measure permeability by relating the inductance and physical core parameters such as core…
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Article
Troubleshooting Distributed Power Systems: Measuring Impedance Using VNAs (2-Port) (Part 4 of the ongoing video series.)

As Part 3 of this video series explained, recently introduced vector network analyzers (VNAs) have made it possible for these frequency domain instruments to…
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Video
Troubleshooting Distributed Power Systems: Measuring Impedance Using Vector Network Analyzers (One-Port Tests) (Part 3 of the ongoing video series.)

Vector network analyzers (VNAs) have always had measurement capabilities that looked like they would be particularly useful in assessing the performance of analog and…
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Video
Troubleshooting Distributed Power Systems: Impedance Is the Critical Measurement (Part 2 of the ongoing video series.)

Whether your goal is to optimize system performance or to troubleshoot issues in distributed power systems, impedance measurement is an indispensable tool. That’s because…
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Video
Target impedance based solutions for PDN may not provide realistic assessment

One of the more common design techniques for power distribution networks (PDN) is the determination of the peak impedance that will assure that the…
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Article
FAQ #23 What Injectors do I need for PDN Measurements?

Our J2112A current injector has been the most requested product to date. It provides a very fast low current pulse, though based on a…
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Article
How to Make Higher Voltage Power-Distribution-Network Measurements

A two-port power distribution network (PDN) measurement is arguably the most accurate method of measuring low-value impedances, such as the output of point of…
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Article
Clock Power Optimization Depends On Jitter Control

Clock-jitter performance has become a top priority among clock, analog-to-digital controller (ADC), and power-supply manufacturers. Why? Simply, it interferes with the performance of digital…
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Article
Assessing Point-Of-Load Regulators Using Non-Invasive Techniques

Evaluating the stability of a Point-Of-Load (“POL”) regulator can be performed using both traditional Bode plot and output impedance measurement techniques. Measuring output impedance…
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Article
FAQ #22: So how does this non-invasive measurement relate to phase margin and gain margin?

It doesn’t, at least not directly. Since stability is an assessment of the proximity of the gain vector to the singular unstable point, (1,0)…
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Article
New Injector Supports Testing of POLs

High Fidelity POL Testing with the J2112A The J2112A: Faster, Non-Invasive, and High Fidelity POL Step Load Testing Testing the step load performance of…
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Article
FAQ #21: How do you use the Picotest injectors and the Agilent analyzer to measure output impedance and/or non-invasive step loading?

How do you use the Picotest injectors and the Agilent analyzer to measure output impedance and/or non-invasive step loading? How do you use the…
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Article
Making Ripple Measurements

Making ripple measurements has traditionally been using an oscilloscope. For a number of technical reasons, an oscilloscope, in general, is not necessarily the best…
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Article
Essential Test Adapters for Your Network / Impedance Analyzer

The network analyzer, sometimes referred to as a Frequency Response Analyzer (FRA) is a common piece of equipment in most of our labs today.…
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Article
Understanding the Data Sheet Key to Effective Circuit Design

Consider this first example excerpt from a datasheet; a plot of the output impedance of a voltage reference with and without a capacitor. Identifying…
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Article
How To Measure Ultra-Low Impedances

High-speed digital circuits need clean power, but can stress power systems in ways that make it difficult for the system to deliver what’s needed.…
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Article
FAQ #20: 2 Port Shunt Thru Impedance Measurement With The Bode 100

2 Port Shunt Thru Impedance Measurement With The Bode 100 Below are a few diagrams on how to do a 2-port impedance measurement and…
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Article
Making The Connection Key To Accurate Test Data

We often give even less thought to how we connect our circuits and systems to the test equipment that we use to power and…
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Article
When Bode Plots Fail Us

It may come as a surprise to some that a control loop’s Bode plot does not always depict the loop stability and that the…
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Article
Evaluate Feedback Stability When There’s No Test Point

It’s impossible to directly measure the stability (gain/phase) characteristics of a device if the device’s control loop lacks an access point to apply a…
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Article
New Test Adapters Improve Your PDN Measurements

This article discusses measurement of small resistances, such as those encountered during PDN measurement, using the OMICRON Lab Bode 100, Keysight E5061B, and the…
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Article
An Unconditionally Stable Linear Voltage Regulator

Is it possible to design an unconditionally stable linear voltage regulator? In fact, many believe that most regulator ICs are unconditionally stable. The answer…
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Article
FAQ #19: What is the difference between a Frequency Response Analyzer (FRA) and a Vector Network Analyzer (VNA)?

What is the difference between a Frequency Response Analyzer (FRA) and a Vector Network Analyzer (VNA)? The FRA is generally designed to measure Bode…
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Article
FAQ #18: What injection resistor value should I use? Is it okay to use a little larger resistor like 30 or 50 ohm instead of 5 ohm (like many app notes recommend)?

What injection resistor value should I use? Is it okay to use a little larger resistor like 30 or 50 ohm instead of 5…
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Article
Extracting Bode Plots from Output Impedance

Many articles and application notes describe the extraction of phase margin, using a non-invasive technique that extracts the phase margin from an output impedance…
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Article
Stability Assessment of Fixed Regulators

There are cases where a Bode (gain?phase) plot cannot be obtained from a control loop. For example, a three terminal regulator or hybrid may…
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Article
Are We Focused On The Wrong Reference Parameters?

Designing a reliable circuit that employs a voltage reference requires a more detailed look at device parameters than most data sheets provide. The key…
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Article
Measuring the Output Impedance of Voltage References and Zener Diodes

In this article we examine the process of measuring a key performance characteristic, output impedance, using the Picotest J2130 DC Dias Injector and the…
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Article
Measuring the PSRR of Voltage References

In this article we detail the process of measuring a key performance characteristic of voltage references, power supply rejection ratio or “PSRR”, using the…
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Article
New Technique for Non-Invasive Testing of Regulator Stability

Output impedance is the key to testing filter and regulator phase margin, even when the control loop is inaccessible. Many voltage regulators are of…
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Article
Selecting Test Signal Injectors

A number of test signal injectors are used when evaluating the performance of power supplies and other low-frequency components with a network analyzer. Network…
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Article
Measuring MOSFET Gate Resistance

The OMICRON Lab Bode 100 Network Analyzer, used in conjunction with the Picotest J2130A DC Bias Injector, is a perfect combination for measuring the…
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Article
FAQ #17: Does the J2110A Bode Box accept both +12V and -12V power supply at the same time?

Does the J2110A Bode Box accept both +12V and -12V power supply at the same time? I saw only one red banana jack and…
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Article
Making Invasive and Non-Invasive Stability Measurements Using the Bode 100 and the PICOTEST J2111A Current Injector

The Picotest J2111A Current Injector, together with the Bode 100, allows direct measurement of the output impedance, group delay and Q of the system.…
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Article

Impedance

How To Verify Control Loop Design

Troubleshooting Distributed Power Systems: Using Current Injectors (Part 5 of the ongoing video series.)

Five Things Every Engineer Should Know About PDN

Oscilloscope Mistakes: #2 (Part 2 of 4)

FAQ #30: Can the Bode 100 measure complex permeability of Inductors/Chokes with some additional adapter and/or equipment?

Troubleshooting Distributed Power Systems: Measuring Impedance Using VNAs (2-Port) (Part 4 of the ongoing video series.)

Troubleshooting Distributed Power Systems: Measuring Impedance Using Vector Network Analyzers (One-Port Tests) (Part 3 of the ongoing video series.)

Troubleshooting Distributed Power Systems: Impedance Is the Critical Measurement (Part 2 of the ongoing video series.)

Target impedance based solutions for PDN may not provide realistic assessment

FAQ #23 What Injectors do I need for PDN Measurements?

How to Make Higher Voltage Power-Distribution-Network Measurements

Clock Power Optimization Depends On Jitter Control

Assessing Point-Of-Load Regulators Using Non-Invasive Techniques

FAQ #22: So how does this non-invasive measurement relate to phase margin and gain margin?

New Injector Supports Testing of POLs

FAQ #21: How do you use the Picotest injectors and the Agilent analyzer to measure output impedance and/or non-invasive step loading?

Making Ripple Measurements

Essential Test Adapters for Your Network / Impedance Analyzer

Understanding the Data Sheet Key to Effective Circuit Design

How To Measure Ultra-Low Impedances

FAQ #20: 2 Port Shunt Thru Impedance Measurement With The Bode 100

Making The Connection Key To Accurate Test Data

When Bode Plots Fail Us

Evaluate Feedback Stability When There’s No Test Point

New Test Adapters Improve Your PDN Measurements

An Unconditionally Stable Linear Voltage Regulator

FAQ #19: What is the difference between a Frequency Response Analyzer (FRA) and a Vector Network Analyzer (VNA)?

FAQ #18: What injection resistor value should I use? Is it okay to use a little larger resistor like 30 or 50 ohm instead of 5 ohm (like many app notes recommend)?

Extracting Bode Plots from Output Impedance

Stability Assessment of Fixed Regulators

Are We Focused On The Wrong Reference Parameters?

Measuring the Output Impedance of Voltage References and Zener Diodes

Measuring the PSRR of Voltage References

New Technique for Non-Invasive Testing of Regulator Stability

Selecting Test Signal Injectors

Measuring MOSFET Gate Resistance

FAQ #17: Does the J2110A Bode Box accept both +12V and -12V power supply at the same time?

Making Invasive and Non-Invasive Stability Measurements Using the Bode 100 and the PICOTEST J2111A Current Injector