The 5-Minute Method for Stabilizing Any Control Loop

By Steve Sandler | January 28, 2020 One method of designing stable control loops is to create an accurate broadband simulation model and to use pole zero compensation to optimize phase margin, gain margin and stability margin…” Click here to read entire article #j2102b #design #ESR #j2100aj2101a #articles #2portshunt #applicationnotes #bode100 #nism #dcdcconverter #noninvasivemeasurement #stability #converter #switchmodepowersupply #spacepower #regulator #bodeplots #controllo

Just How Fast is GaN Fast?

By Steve Sandler | March 12, 2020 “I recently designed an ultra-high speed, low-impedance pulse generator (Figure 1). I wanted it for evaluating oscilloscope probe performance [1], [2] and for determining the feasibility of an in-socket load for ASIC emulation. The obvious choice, due to size and desired performance, was an eGaN FET. One of the devices I used is an EPC2037, 0.9 mm device. As it turns out, the hard part wasn’t designing the pulser, but determining just how fas

The Myth of Three Capacitor Values

By Eric Bogatin, Larry Smith, and Steve Sandler | March 3, 2020 “Many designs today include three different value decoupling capacitors, or when using just one capacitor, a small value like 0.1 uF. These recommendations are based on 50-year-old assumptions that do not apply today. It is time to reconsider these out of date, legacy design guidelines….” Click here to read the entire article #j2102b #powerdistributionnetwork #design #ESR #flatimpedance #powerintegrity #articles

Measuring a Scope Probe Requires Two Oscilloscope Channels and a Very Flat Signal Source

Oscilloscope users can also calibrate their passive oscilloscope probes, though the process is much less sophisticated and for lack of a better term, wrong.  The calibration process also generally can’t include the “fixture.” This short article shows you what to measure and a method to accurately measure the response of the probe.  In addition to the probe, there are other errors that need to be removed.  Most importantly, this article will show you how to accurately measure

Earn IEEE CEU/PDHs and learn the latest design techniques at EDI CON University

All conference pass holders are eligible to attend, but pre-registration happens during the registration process. After attending an EDI CON University course, attendees can earn IEEE Continuing Education Unit/Personal Development Hour (CEU/PDH) certificates and enjoy a complimentary lunch on the expo floor. This year’s EDI CON University sessions are sponsored by Teledyne LeCroy, Mini-Circuits and Keysight Technologies. CLICK HERE to register today. Write a short essay to su

EDI CON USA 2018 Announces EDI CON University

All conference pass holders are eligible to attend, but pre-registration happens during the registration process. After attending an EDI CON University course, attendees can earn IEEE Continuing Education Unit/Personal Development Hour (CEU/PDH) certificates and enjoy a complimentary lunch on the expo floor. This year’s EDI CON University sessions are sponsored by Teledyne LeCroy, Mini-Circuits and Keysight Technologies. CLICK HERE to read the full article and see this year’s

Characterizing and Selecting the VRM

The voltage regulator module (VRM) is at the foundation of power integrity, making proper selection essential. There are thousands of VRMs and VRM controllers available from many manufacturers. They are often selected based on size, efficiency, price, or a relationship with the manufacturer. This often leads to a poor VRM selection, requiring additional engineering resources, greater time to market, as well as higher BOM costs to correct the deficiencies. Even after the VRM o

Accurately measure ceramic capacitors by extending VNA range

Ceramic capacitors play an oversized role in circuit performance as a major contributor to voltage regulator control loop stability and power delivery network (PDN) impedance. When designing with these circuit staples, you need good impedance data over a wide frequency range. Proper measurement technique is the key to making accurate measurements. Here’s how to use two simple techniques that result in accurate, wideband, frequency measurements by extending the range of a vect

Designing Power for Sensitive Circuits

What is a sensitive circuit? Sensitive circuits are those that can easily be degraded by power supply noise.  These circuits generally include oscillators, LNAs, transceivers, mixers and ADCs. I’ll probably receive emails from many readers adding to my list, and justifiably so, so take these as a few examples and not a comprehensive list. Click here to read the entire article. #noise #articles #j2120a #psrr #powersupply #impedance

Top Three EMI and Power Integrity Problems with On-Board DC-DC Converters and LDO Regulators

Kenneth Wyatt Wyatt Technical Services, LLC ken@emc-seminars.comSteve Sandler Picotest steve@picotest.com Modern devices are continuing a long-term trend of squeezing more electronics into smaller packages, while also increasing system performance, data rates and operating efficiency. Higher efficiencies are often achieved by implementing faster silicon MOSFETs or even faster eGaN FETs while size is reduced by increasing switching frequencies and replacing aluminum and ta

Optimizing Arduino and the AD9851 DDS signal generator

Arduino has taken the product “maker” world by storm and one of the more popular Arduino modules is the Analog Devices AD9851 DDS waveform generator. Internet forums are filled with discussions related to two specific issues. One issue is that the output amplitude is not constant with frequency, requiring a level control loop. The second issue is that the distortion gets pretty horrific, particularly at higher output frequency settings. In this article, we’ll show how to corr

How to measure the world’s fastest power switch

Gallium Nitride (GaN) FETS are poised to replace silicon power devices in voltage regulators and DC-DC power supplies. Their switching speeds are significantly faster and their RDS(on) is lower than silicon MOSFETS. That can lead to higher power efficiency power sources, which is good for all of us. If you’re designing power circuits with GaN devices, you need a grasp of the device’s switching speed. To measure that, you’re oscilloscope, probes, and interconnects must be fast

Impedance measurements stabilize op-amp buffers

Figure 1. Op amps are often used as unity gain signal buffers, which are not as simple to use as it may appear. The unity-gain op amp (operational amplifier) buffer circuit is routinely used to transform high-impedance inputs into low-impedance outputs. ADC (analog-to-digital converter) voltage references are also frequently buffered to reduce the voltage reference noise resulting from the ADC sampling current. When implemented well, using an appropriate op amp, the results w

Essential 1-Port PDN PROBE: Applications Abound

BROWSER-CLASS PROBE Several companies manufacture and distribute high-frequency TDR probes. These probes are typically designed for very high-frequency measurement, typically 10GHz or more. These probes are designed to be used in sophisticated probe stations with microscope-supported tip placement. 1-port PDN probes, such as the Picotest P2100A shown in figure 1, are designed to be handheld browser probes. The handheld browser probe shown is a lower frequency probe, supportin

Simple trick to measure plane impedance with a VNA

Having said all of this, the measurement of a PCB plane using a VNA may not be as straightforward as you might expect. One simple trick makes it easy. A 2-sided 63mil FR4 PCB is used as an example in this article. The PCB is measured using both a VNA and a TDR. The results are compared, the error source is identified, and the trick is employed to correct the error. The PCB is shown in Figure 1 connected to a SD-24 20GHz/17.5ps sampling head installed in a Tektronix 11801B DSO

Match impedances when making measurements

Recently, I used a shielded coaxial cable to measure power supply ripple and the results were even noisier than using an oscilloscope probe. How can that happen? Doesn’t the shielding reduce noise? I even measured my setup using a signal generator and it all looks ok. So what was wrong? On the surface, it seems like a great idea to use a shielded cable to measure noise. In reality, it is a great idea to use a coaxial cable to measure ripple and noise and you can gain the bene

Three Stability Assessment Methods Every Engineer Should Know About

Many engineers are familiar with the Bode plot as an effective stability assessment method. However, some authors suggest and even teach that the Bode plot is the only method needed. This article shows why this thinking is short-sighted. A single, low cost instrument that can produce Bode plots, as well as two other stability assessment methods is discussed providing a more comprehensive stability assessment set of guidelines. A single word illustrates why Bode plots cannot b