High-Speed PCB Design (DS1-1-43)

SynopsisIn the past, those working in the digital field share little commonality in terms of theories, analysis, and design principles with their counterparts who work with RF/microwave frequencies. Today however, the line of separation is blurring due to the reduction in digital signal transition time or the consequent rise in bandwidth requirement.

The underlying knowledge for those working in these fields is RF/microwave theories or in their more basic forms, the Maxwell's Equations. EMI forms the subset of knowledge within the area of signal integrity. Hence this course imparts first the RF/microwave theories before going into discussion on signal integrity and EMI.

Whether a circuit is "high-speed" or not depends on the signal transition time. Hence this course is relevant not only for those working with high-speed clock but for almost all circuit design engineers who have seen their signal transition time reducing over time.

What previous participants say about this course
Answers to the question 'what did you like most about the course'
• "The example of designing the trace. The explanatory with example showing us the match & mismatch of impedance of the line" - 14 Dec 04
• "Clear explanation, teaching stuff (get to know by apply the fundamental knowledge), demo of application & software & arrangement of food / rest time" - 27 June 05
• "Broad coverage of EM field theory and direct application" - 20 Dec 05
• "Learning of software tools for the circuit characteristic simulation" - 18 Jan 06
• "The theories behind the rules of layout" - 6 Aug 08
• "Examples with illustrations. Lots of fundamental theories that relate to real world design" - 6 Aug 09
• "Going back to the basics of electrical and EM theory & how it affects the design of our circuits" - 26 May 10
• "ADS simulation on certain practical cases" - 30 Mar 11

What You Will Learn

• Relevant concepts/tools for tackling high-speed digital design issues, such as transmission line theories, crosstalk, differential signalling, understand the mechanism of electromagnetic interference (EMI), useful calculator/software, and rules of thumb.
• Practical layout techniques for high-speed PCB in order to tackle signal integrity (SI) and electromagnetic interference (EMI) issues. 

Who Should AttendTechnicians and engineers who work with digital circuits in the role of:

• product marketing
• application engineering
• design and development
• test development
• product engineering
• testing
• system architect
• PCB layout specialist
• EMC specialist

PrerequisiteTechnical background or working experience with PCB layout for digital circuit.

Course MethodologyThis course is presented classroom style, with case studies to illustrate the concepts taught. Usage of industry-leading electronic design automation software such as Agilent ADS or Agilent Genesys or LTSpice will be demonstrated.

Course Duration3 days, 9am - 5pm

Course StructureDay 1
Review of PCB Interconnect Structures and Component Packaging

• Brief review of multi-layer PCB technology and terminology (fabrication, material, cost)
• Integrated circuit packaging

Introduction to Signal Integrity

• Problem statement - PCB interconnection and electrical signal distortion
• Definition of SI, EMI and EMC
• What do we mean by "high-speed" and the related problems
• Time and frequency domain representation of signals
• Bandwidth estimation of digital signals

Transmission Line and Signal Propagation

• Lumped versus distributed circuit
• PCB traces as transmission line - planar transmission line configurations
• Digital signals and transmission line - characteristic impedance, delay, attenuation, reflection and dispersion
• Termination techniques for transmission line (Series, Parallel, RC, etc)
• Discontinuities in transmission line
• Transmission line design for PCB

Signal Return Path and EMI

• How does electrical current return to its source
• Perforation and splits in reference plane
• Common mode currents
• Basic grounding rules to minimize interference
• Layout techniques for minimizing EMI

Hands-on Session: Demonstrating SI issues via simulation/measurement

Day 2
PCB Stack-up

• What factors to consider when making a PCB stack-up
• How to control trace impedance (Zo) for microstrip, stripline, grounded co-planar line
• Criteria of a PCB stack-up configuration that promote good SI
• Steps in making a PCB stack-up

Differential Signaling

• Motivation for differential signaling
• Common-mode and differential-mode signal propagation
• EMI issues on differential signaling
• Termination techniques for differential signaling
• Tightly coupled and loosely coupled lines
• Controlling differential impedance on differential pair
• Differential transmission line design on PCB

Hands-on Session: Demonstrating SI issues via simulation/measurement

Day 3
Crosstalk

• Crosstalk and the effects on signal
• Near-end and far-end crosstalk
• Crosstalk on microstrip vs stripline
• What factors can be controlled for minimizing crosstalk
• Layout techniques for minimizing crosstalk

Simultaneous Switching Noise (SSN) and Ground Bounce

• What causes ground bounce
• Effect of ground bounce on driver/receivers voltage levels
• How to minimize ground bounce problem

Decoupling Capacitors

• Power Distribution Network and decoupling capacitors
• Effects of equivalent series inductance (ESL) on capacitors
• Package vs inductance
• Placement and layout techniques that minimize loop inductance

Quality high-speed PCB Design Procedure

• Steps in designing high-speed boards
• What analysis is required
• Useful rules for achieving good SI
• Timing skew adjustment
• Case study

Hands-on Session: Demonstrating SI issues via simulation/measurement