Dr. Johnson's Signal Integrity Lab (SiLab)

Independent Films

Parasitic Inductance of a Bypass Capacitor  

The pads and vias associated with a surface-mounted bypass capacitor exert tremendous influence over its high-frequency performance. This laboratory session presents a simple intuitive model of the electrical behavior of pad and via structures, illustrating in a direct way the importance  of good layout.

Quantitative measurements of the inductance of particular surface-mounted bypass capacitor layouts appear in the video. After watching this session you will be able to just look at a surface-mounted structure and estimate its inductance.

Pricing and Terms

Via Inductance    

Each via on your pcb exhibits both capacitive and inductive effects. This session focuses on the inductive properties of an individual multi-layer via.

Dr. Johnson constructs a working large scale model of a via, large enough so the he can reach into the board and modify the structure from within while observing, in real-time, the electrical behavior of the via.

The presentation emphasizes the importance of good interplane connections near those locations where high-speed signals traverse vertically through your layer stack.

Pricing and Terms

Metastability      

What happens when you violate the setup and hold times on a flip-flop? Sometimes it goes to one, sometimes it goes to zero, and sometimes - this is the subject of metastability - it takes a long time to make up its mind.

Dr. Johnson demonstrates the principal of metastability in a direct and unambiguous way, leaving you with a deep and lasting understanding of why the effect happens, how it behaves, and what you can do to manage its impact on system reliability.

Pricing and Terms

Pricing and Terms

Some films we produce independently. Others are sponsored by companies with an interest in technical education and distributed through their respective web sites.

The films listed above this notice were produced independently and we sell them here on this site. Each video costs (North American DVD format): $40 each plus $2.50 shipping for up to three titles within the US. To order, use our online form and pay with your credit card, or print an order form and mail it with payment to Signal Consulting. Checks and major credit cards accepted. Please allow 3 weeks for delivery.

Please note that our independent films are copyrighted and are licensed for individual use only. For information about obtaining a department-wide or corporate-wide license, please contact us at 509-997-0505.

The films listed below this notice are sponsored by the companies listed, and are available through their respective web sites under different pricing and terms.

Distributed by Xilinx Corp.

(see www.Xilinx.com)

Signal Integrity Techniques for Platform FPGA Design

(Information applicable to any BGA package having solid power and ground planes)

 

Ever wondered why big chips have so many power and ground pins? This film explains why. Also called "BGA Ground Ball Placement", the main topic is crosstalk, specifically, the crosstalk that occurs underneath a BGA package in the spaces between the balls and your pc board. The presentation begins with a simple current-loop experiment illustrating the nature of magnetic (inductive) coupling, and then moves to a large-scale model of a BGA package where the principles of inductive crosstalk are easily observed. Dr. Johnson modifies, in real time, the pattern of power and ground pins within the package while observing the difference in crosstalk obtained with various patterns. He compares power-and-ground pin patterns for Xilinx Virtex-4 and Altera Stratix-II FPGA packages, and discusses the efficacy of using virtual ground, or
soft-ground, connections to mitigate crosstalk.

Signal Integrity Techniques for RocketIO Transceivers (two-part set)

(Information applicable to any high-speed serial link)

RocketIO serial transceivers can go at 10 Gb/s, but can you? Bolster your knowledge of high-speed layout techniques with this two-part series, chock full of guidelines and tips for successful RocketIO implementation.

Part I, "A Signal Integrity Introduction to RocketIO Transceivers", begins with a laboratory demonstration of a 10Gb/s serial NRZ (binary) link tranversing a 30” pcb channel. Dr. Johnson then works through the design piece by piece, focusing on the design and layout of well-balanced pcb differential pairs, AC-coupling capacitors, and connectors.

Part II, "Loss Budgeting for RocketIO at 10 Gb/s", presents a simple link attenuation budget for a serial link. The film provides raw data for estimating pcb trace skin effect loss, dielectric loss, plus the effects of layer transitions, vias, and other imperfections along the transmission path. It concludes with a summary of the various equalization techniques used in the RocketIO family.

Distributed by X2Y Attenuators

(see www.x2y.com)

Low Inductance Capacitor Packages       

(Information applicable to power delivery in all high-speed digital designs)

Each year brings a new crop of surface-mounted capacitor packages, including many varieties touting "low inductance". Dr. Johnson explains the importance of low-inductance capacitor structures and shows how they affect real digital systems. The film discusses the measurement of low-inductance capacitors and the impact of layout and positioning. A handsome animation by Dr. Bruce Archambeault illustrates the concept of distributed plane behavior. The film includes actual measurements of ordinary 0402 capacitors versus X2Y-brand low-inductance types, both in
the frequency domain on test structures and in the time domain on a working FPGA design. The film concludes that in many designs you may replace ordinary 0402 capacitors with X2Y components at a 3:1 ratio (i.e., three times fewer X2Y components are required).