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Signal Integrity

PCB Teardrops on Differential Pairs

Should You Place Teardrops on Differential Pairs? We’ll look at an interesting question from an OnTrack podcast guest about teardrops on differential pairs. Will they create signal integrity problems? Read Article

NVMe M.2 PCIe connector stubs

A Brief Study of Stubs on a PCIe Connector Stubs are an important topic in high-speed PCB design, and there is a longstanding guideline that stubs should always be removed from all vias on high-speed digital interconnects. While stubs are bad for high-speed lines, they do not always need to be removed. What is more important is to predict the loss profile and frequencies, and to floorplan appropriately to try and prevent such losses. In this article, I’ll look at some simulation results Read Article

ground below inductor

Are PCB Ground Planes Placed Under Inductors in Switching Regulators? Should you place a ground cutout beneath the inductor in a switching regulator PCB layout? This is an important question surrounding EMI/EMC, and we’ll investigate in this article. Read Article

skew sources high speed PCB

Addressing Skew Sources in High Speed PCBs Sometimes, when we talk about skew, we aren't as specific as we should be. Most discussions of skew and jitter deal with the type of skew incurred during routing, namely due to length mismatches in differential pairs and fiber weave-induced skew. In fact, there are many different sources of skew that contribute to total jitter on an interconnect, and it's important to quantify these in serial and parallel buses that require precise timing control Read Article

Pin-Package Delay and Via Delay

Pin-Package Delay and Via Delay in High Speed Length Tuning Take a look at the inside of some integrated circuit packages, and you’ll find a number of wires bonded to the semiconductor die and the pads at the edge of the component's package. As a signal traverses makes its way along an interconnect and into a destination circuit, signals need to travel across these bond wires and pads before they are interpreted as a logic state. As you look around the edge of an IC, these bond wires can have different Read Article

Guide to Using Ferrite Beads in a PCB

Ebook: Guide to Using Ferrite Beads in a PCB Ferrite beads in a PCB are the stuff of myth, but there are legitimate uses for ferrite beads and other ferrite components. In this e-book, we’ll examine some uses of ferrite beads in a PCB, as well as other magnetics. Read Article

PCB copper roughness

How Much PCB Copper Surface Roughness is Too Much? When we talk about copper roughness, we always bring it up as if it were a universally bad thing. The fact is, some circuits will always function just fine even if the copper is rough. As long as your traces are fabricated to spec in every other area, the roughness of the traces might not matter as long as your operating frequency or bandwidth are low enough. Just what constitutes “low enough” and when is the effect of roughness so small that we Read Article

PCB Copper Foil

Types of PCB Copper Foil for High-Frequency Design Does your design need smooth PCB copper foil? It all depends on the frequency range you’re working in. Learn more in this article. Read Article

Transmission Line Impedance Calculator

PCB Transmission Line Impedance Calculators We’ve compiled a set of transmission line impedance calculators for use in high speed PCB design and RF design. Read Article

Mode-Selective Transmission Line

Harness mmWave Routing with a Mode-Selective Transmission Line High frequency and data rate channels can be routed as a mode-selective transmission line. Here’s when you should consider this routing technique. Read Article

Parasitic Extraction with an Electromagnetic Solver in PCB Routing

Parasitic Extraction with an Electromagnetic Solver in PCB Routing Parasitic extraction: the integrated circuit design community must grapple with this task on a daily basis, especially once gate features are reduced below ~350 nm and chips run at high switching speeds. The PCB community also has to deal with this idea in order to better design power delivery networks, interconnects with precise impedance, and properly quantify crosstalk and coupling mechanisms. There are many 3rd party applications that can be Read Article

Stripline impedance calculator

Stripline Impedance Calculator Learn more about using and interpreting results from a microstrip impedance calculator. Read Article

Microstrip impedance calculator

Microstrip Impedance Calculator Learn more about using and interpreting results from a microstrip impedance calculator. Read Article

Grounded coplanar waveguide digital signal

Altium Live Question: Digital Signals in a Grounded Coplanar Waveguide? Have you considered the effects of a GPCW structure on digital signals? Here’s a hint: look at the S-parameters! Read Article

Mode conversion

A Guide to Mode Conversion, Its Causes, and Solutions Differential pairs are most often discussed in terms of their impedance and length matching tolerance, both with the goal of ensuring proper termination at the receiver and suppression of common mode noise. On interconnects, such as board-to-board connections or cascaded transmission line arrangements, you have an important EMC compliance metric that is sometimes overlooked. This is mode conversion, which can be visualized in an S-parameter Read Article

Differential stripline impedance calculator

Differential Stripline Impedance Calculator Try our differential stripline impedance calculator, built based on Wadell’s equations. Read Article

Differential Microstrip Impedance Calculator

Differential Microstrip Impedance Calculator Learn more about using and interpreting results from a differential microstrip impedance calculator. Read Article