On Site Surface Mount Technology Training Courses > PCB Design of High Speed Circuits

PCB Design of High Speed Circuits

High-speed circuitry is used in all modern products. Understanding high-speed fundamentals and the relationship of speed to distance and how to apply this knowledge is the key to successful designing. Any significant noise problems at the system level can be very expensive and must be solved at the board level during layout. But yet board costs must be managed properly. It is easy to over-design a product, have unnecessary layers and drive the cost of a product up too high.

In this course the focus is on what must be understood to take the schematic and transform it into a working PCB design while keeping costs under control. Emphasis is on digital circuits, though it also is just as applicable to analog. Information presented in this course can be applied to high-speed digital and analog designs up into the GHz range.

This onsite SMT training course can be held at your facility. Minimum class size is 5 to 10 students. Please email us or call 519-260-0596 to request a quotation.

Who Would Benefit

The book will be of immense value to both circuit designers as well as CAD designers, and those involved in product testing, troubleshooting and debug.

Course Materials * Please note you are not required to enroll in the onsite course to purchase this book.

Course Outline

1) Basics of High Speed & Switching

This course starts off defining what a high-speed signal is, where they are used and on what kinds of conductors, how high-speed impacts products, terms necessary to present and understand high-speed such as risetime. Next, how analog compares as well as what a signal is made up of, the harmonics, frequency and time domain values. Finally, velocity and the common units of length round out this section.

2) Substrate Materials & Fabrication

The successful design, when high-speed circuits are present, must focus on the materials the signals have to transmit through. In this section information is presented about board material, dielectric constant values, the effects of frequency, core material types and thickness, prepreg and thickness, resin, moisture effects, copper foil, fabrication panels, layer stack-ups, fabrication process, copper weight and resistance, copper losses, test coupons, TDR measurements, velocity and propagation delays for different layers, dissipation factor and variances.

3) Packages & Connectors

In this section information is presented about SMT package lead capacitance and inductance, why they can be detrimental, smaller package advantages, the trend towards smaller packages, using MCM's, SOC's, mixing technologies, lower profile packages, propagation delay reductions, higher frequencies in the future, reduction in supply voltage trends, decoupling, different types of connectors and controlled impedance, power and ground connections.

4) Semiconductor Devices

The material presented in this section includes information about driver characteristics, device inputs and their characteristics, timing problems, trends in semiconductors, high-speed semiconductors, RF devices, types of digital most used, risetime, supply voltage vs. risetime, propagation delay vs. supply voltage, Vcc and ground bounce, typical driver characteristics, future performance, internal terminators, power and ground leads, decoupling, about decoupling caps and their contribution.

5) Transmission Lines & Microstrips

Transmission lines are all around us. In this section the students learn what a transmission line is, optimum impedance, the effects of laminate and frequency on impedance, reactance formulas, reflections, load separation, lump and radial loading, microstrips, their use and the equations for, imbedded microstrips, their use and its equations.

6) Striplines & Differential Pairs

The information in this section will cover symmetrical and asymmetrical striplines, the model, use, equations, stack-ups and plots for each. Also there is material about differential pairs, use, design equations, types, using wires and micro-strips.

7) Stack-Ups & Planes

This section deals with the design characteristics of a printed circuit board. Topics include trace width, why stack-ups are important, common design mistakes, internal caps, thickness, hole and pad sizes, 2-layer, 4-layer, 6-layer, and 8-layer boards and stack-ups, routing with common trace sizes, quiet planes, via effects, BGA ground planes, signal across gaps, noisy planes, buried resistors, and right angle bends.

8) Coupling & Parallelism

Coupling primarily is determined by spacing between lines. When signals are routed close to one another there can be a sharing of radiated pulse energy that can cause problems. In this section information is presented about the fields for switching, what is coupling and the types, types of inductive coupling, source and victim, factors affecting inductive coupling, forward and backward crosstalk, parallelism, capacitive coupling, symmetrical and asymmetrical stripline inductive coupling, embedded micro-strip coupling, crosstalk tolerance and management.

9) Impedance Control & Reflections

When nets on a design equal or exceed the transition length reflections will be created. In this section this matter is dealt with. There are instances when reflections are intended and useful, others where reflections can be tolerated, and still others where reflections will create serious problems. Each of these instances shall be presented and dealt with. Also information is presented about when a line acts as a capacitor vs. a transmission line, the symptoms of noise problems, whether all noise is a problem, circuits sensitive to switching vs. voltage levels, cause of reflections, trace width changes, improper trace widths, matching loads, TTL/CMOS as loads, stubs, when stubs are shorts and how to calculate, effects of changing dielectrics, terminators, coupling problem, and ground traces around sources.

10) Terminators & Buses

This section contains information on a typical circuit, circuits that do not need termination, short interconnects, net length analysis, reflections, critical nets, parallel terminator, types, location and design, matching terminator to line, series terminator value and location, mid-terminators, terminating differential pairs, terminating backplanes, handling bus lines, and packages for terminators.

11) Design Preparation

In this section information is presented about the steps in design, worse case possibilities, BGA part impact, determining layer count, assigning layers, net design rules, package selection impact, test structures, trace widths and spaces, parallelism rules, routability, cable connections, critical net noise, net routing, stub use, schematic changes, and implementing terminators.

12) Setting Up Design Rules

This section presents information about setting up design rules, the type of circuitry, optimum impedance, rules for selecting trace width, determining fundamental and third harmonic bandwidth frequencies, transition and critical length, stub length, placement, sequential nets, handling sequential nets, routing, handling nets and termination, double-driven nets and termination, center drive nets and termination, connectors on nets, analyzing designs after routing.

13) Noise Margins & Budgets

Understanding noise margins are key to determining how much noise can be tolerated. In this section information is presented about common symptoms, device families, noise sensitive devices, output drive vs. input voltages, noise margins, noise budget, calculating noise margins, multiple devices on a net, noise due to reflections, crosstalk, other factors affecting noise budget, planes, circuit failures, and solving noisy system design problems.

14) Power Distribution

The design of the power distribution system for high-speed circuits requires special attention. This section provides information about planning the planes, power and ground plane capacitance, sources of switching transients, simulating transients, circuits susceptible to switching transients, effect of bulk capacitors, value of bulk capacitors, modeling bulk capacitors, ferrite bead types and characteristics, power and ground connections, low vs. high frequency return paths, and oscillator hookup.

15) Documentation

The documentation supplied for fabrication is very important. This section presents why documentation is important, types needed, hole chart info, feature chart info, film set chart, cross-section drawing details, fabrication drawing, datum location, fabrication notes, test coupons, internal R&C layers, and a simple structure to check for proper stackup.

Instructor: James C. Blankenhorn

Onsite Training Costs

The cost for performing an onsite course is separated into three items, all prices are approximate and in US funds:

Instruction Fee is $1500 to $3000 per day depending upon the topic and your location.

Student materials are quoted:
Book materials range from $75 to $300 depending upon the course.
CD-ROM materials range from $485 to $995 depending on the course.

Onsite Quotes Provided

Contact us and receive a quotation and details for any course you would like to have. There is no obligation.

You may also contact us by phone 519-260-0596 or fax 519-260-0597.