Complete PCB Design Using OrCAD Capture and PCB Editor

Cover
Complete PCB Design Using OrCAD® Capture and PCB Editor
Copyright
Acknowledgments
Introduction
1 Introduction to printed circuit board design and computer-aided design
	Computer-aided design and the OrCAD design suite
	Printed circuit board fabrication
		Printed circuit board cores and layer stack-up
		Printed circuit board fabrication process
		Photolithography and chemical etching
		Mechanical milling
		Layer registration
	Function of OrCAD PCB Editor in the printed circuit board design process
	Design files created by PCB Editor
		PCB Editor format files
		Artwork (Gerber) files
		Printed circuit board assembly layers and files
2 Introduction to the printed circuit board design flow by example
	Overview of the design flow
	Creating a circuit design with Capture
		Starting a new project
		Placing parts
		Wiring (connecting) the parts
		Creating the PCB Editor netlist in Capture
	Designing the printed circuit board with PCB Editor
		The PCB Editor Window
			Controlling the view
		Drawing the board outline
		Placing parts
			Moving and rotating parts
		Routing the board
			Using the autorouter
			Manual routing
			Performing a design rule check
		Creating artwork for manufacturing
3 Project structures and the PCB Editor tool set
	Project setup and schematic entry details
		Capture projects explained
		Capture part libraries explained
	Understanding the PCB Editor environment and tool set
		Terminology
		PCB Editor windows and tools
		The design window
		The toolbar groups
			Application mode group
			Edit group
			View group
			Setup group
			Shapes group
			Manufacture group
			Display group
			Miscellaneous group
			Place group
			Route group
			Add group
		Control panel with foldable window panes
			Visibility pane
			Find filter pane
			Options pane
		Command window pane
		World view window pane
		Status bar
		Color and visibility dialog box
		Cross-section Editor (layer stack-up) dialog box
		Constraint manager
			Padstack editor
		Manufacturing artwork and drill files
		Understanding the documentation files
4 Introduction to industry standards
	Introduction to the standards organizations
		IPC—Association Connecting Electronics Industries
		Electronic Industries Alliance
		JEDEC Solid State Technology Association
		International Electrotechnical Commission
		Military standards
		American National Standards Institute
		Institute of Electrical and Electronics Engineers
	Classes and types of printed circuit boards
		Performance classes
		Producibility levels
		Fabrication types and assembly subclasses
		IPC land pattern density levels
	Introduction to standard fabrication allowances
		Registration tolerances
		Breakout and annular ring control
	Printed circuit board dimensions and tolerances
		Standard panel sizes
		Tooling area allowances and effective panel usage
		Standard finished printed circuit board thickness
		Core thickness
		Prepreg thickness
		Copper thickness for plated through holes and vias
		Copper cladding/foil thickness
		Copper trace and etching tolerances
		Standard hole dimensions
		Soldermask tolerance
	References
	Further reading
5 Introduction to design for manufacturing
	Introduction to printed circuit board assembly and soldering processes
		Assembly processes
			Manual assembly processes
			Automated assembly processes (pick and place)
		Soldering processes
			Manual soldering
			Wave soldering
			Reflow soldering
	Component placement and orientation guide
		Component spacing for through-hole devices
			Discrete through-hole devices
			Integrated circuit through-hole devices
			Mixed discrete and integrated circuit through-hole devices
			Holes and jumper wires
		Component spacing for surface-mounted devices
			Discrete surface-mount devices
			Integrated circuit surface-mount devices
			Mixed discrete and integrated circuit surface-mount devices
		Mixed through-hole devices and surface-mounted devices spacing requirements
	Footprint and padstack design for printed circuit board manufacturability
		Land patterns for surface-mounted devices
			Surface-mounted device padstack design
			Surface-mounted devices footprint design
		Land patterns for through-hole devices
			Footprint design for through-hole devices
			Padstack design for through-hole devices
			Hole-to-lead ratio
			Plated through hole land dimension (annular ring width)
			Clearance between plane layers and plated through holes
		Soldermask and solder paste dimensions
	References
6 PCB design for signal integrity
	Circuit design issues not related to PCB layout
		Noise
			Background noise
			Intrinsic noise
		Distortion
		Frequency response
	Issues related to PCB layout
		Electromagnetic interference and cross talk
		Magnetic fields and inductive coupling
		Loop inductance
		Electric fields and capacitive coupling
	Ground planes and ground bounce
		What Ground is and what it is not
		Ground (return) planes
		Ground bounce and rail collapse
		Split power and ground planes
	PCB electrical characteristics
		Characteristic impedance
		Reflections
		Ringing
		Electrically long traces
		Critical length
		Transmission line terminations
	PCB routing topics
		Parts placement for electrical considerations
		PCB layer stack-up
		Bypass capacitors and fan-out
		Trace width for current-carrying capability
		Trace width for controlled impedance
	Topologies, Z0, TPD, trace width, and trace separation design equations for various transmission lines
		Trace spacing for voltage withstanding
		Trace spacing to minimize cross talk (3w rule)
		Traces with acute and 90 degree angles
	Using PSpice to simulate transmission lines
		Simulating digital transmission lines
		Simulating analog signals
	References
7 Making and editing Capture parts
	The Capture part libraries
	Types of packaging
		Homogeneous parts
		Heterogeneous parts
		Pins
	Part editing tools
		The Select tool and Settings
			? Select tool
			? Snap to Grid
			? Area Select method
			? Drag connected object mode
		The Pin tools
			? Place Pin tool
			? Place Pin Array tool
		The Graphics tools
			? Place IEEE Symbol
			? Place Line tool
			? Place Polyline tool
			? Place Rectangle tool
			? Place Ellipse tool
			? Place Text tool
			? Place Elliptical Arc tool
			? Place Bezier Curve tool
			Place Picture tool
		The Zoom tools
			? Zoom In
			? Zoom Out
			? Zoom to Region
			? Zoom to All
	Methods of constructing Capture parts
		Method 1. Constructing parts using the New Part option (Design menu)
			Design example for a passive, homogeneous part
			Design example for an active, multipart, and homogeneous component
			Assigning power pin visibility
			Design example for a passive, heterogeneous part
		Method 2. Constructing parts with Capture using the Design Spreadsheet
		Method 3. Generating or copying the schematic symbols from other sources
		Method 4. Generating parts with the PSpice Model Editor
			Generating a Capture Part Library from a PSpice Model Library
			Making and/or obtaining PSpice libraries for making New Capture parts
			Downloading libraries and/or models from the Internet
			Making a PSpice Model from a Capture project
			Adding PSpice templates (models) to preexisting Capture parts
	Constructing Capture symbols
8 Making and editing footprints
	Introduction to PCB Editor’s symbols library
		Symbol types
	Composition of a footprint
		Padstacks
		Graphical objects
		Text
		Minimum footprint requirements
		Optional footprint objects
	Introduction to the Padstack Editor
		Start tab
		Drill tab
		Secondary Drill tab
		Drill Symbol tab
		Drill Offset tab
		Design Layers tab
		Mask Layers tab
		Options tab
	Footprint design examples
		Example 1. Design of a through-hole device from scratch
			Designing the through-hole padstack
			Designing a through-hole footprint symbol
			Controlling text size
		Example 2. Design of surface-mount device from an existing symbol
			Modifying an existing symbol: determining design requirements
			Replacing a padstack definition
		Example 3. PGA or BGA package design using the Symbol Wizard
	Flash symbols for thermal reliefs
	Mechanical symbols
		Mounting holes
		Creating mechanical symbol drawings
		Placing mechanical symbols on a board design
	Blind, buried, and microvias
	OrCAD Library Builder
	3D canvas
		Bending the rigid-flex printed circuit board in 3D canvas
	References
9 Printed circuit board design examples
	Introduction
	Overview of the design flow
	Example 1. Dual power supply, analog design
		Initial design concept and preparation
		Setting up the project in Capture
			Drawing the schematic with Capture
			Placing parts
			Connect parts with wires (signal nets)
			Making power and ground connections
		Preparing the design for PCB Editor
			Grouping related components (rooms)
			Annotation
			Cleanup Cache
			Performing a schematic design rule check in Capture
			Generating the netlist for PCB Editor
			Problems during netlist creation
		Setting up the board
			Setting up the extents (work area boundary)
			Controlling the Grid
			Making a board outline
			Adding dimension measurements
			Adding mounting holes
			Placing parts
			Intertool communication
			Using cross-probing to place parts
			Rotating parts
			Mirroring parts
			Changing a part in capture
			Performing an engineering change order
			Controlling layer visibility
			Controlling net visibility
			Cross-highlighting between Capture and PCB Editor
			Finding parts using the Find filter pane
		Design rule check and status
			Using the Status dialog box
			Generating design rule check reports
			Design rule check error markers
		Defining the layer stack-up
			Setting up the Layout Cross Section
		Pouring copper planes
			Pouring a copper plane using the setup → Outlines Option
			Pouring a copper plane using the Shape Add Tool
		Verifying connectivity between Pins and Planes
			Adding thermal reliefs and clearances to padstacks
		Defining trace width and spacing rules
			Determining trace width
			Assigning vias
			Determining trace spacing requirements
		Prerouting the board
			Routing fan-outs for power and ground
			Moving and deleting fan-outs
		Manually routing traces
			To begin manually routing traces
			Locking (fixing) traces
			Running the autorouter
		Finalizing the design
			Postrouting inspection
			Checking routing statistics
			Cleaning up a design by glossing
			Synchronizing the design with Capture (back annotation)
	Example 2. Mixed analog/digital design using split power, Ground planes
		Mixed-signal circuit design in Capture
			Power and ground connections to digital and analog parts
			Connecting separate analog and digital grounds to a split plane
			Using buses for digital nets
		Defining the layer stack-up for split planes
			Defining the layer stack-up
			Setting up a split GND Plane
			Setting up separate planes on a single plane layer
		Setting up routing constraints
			Adding Route Keep-Out areas
			Moving a routed trace to a different layer
			Adding Ground Planes and guard traces to Routing layers
			Routing guard traces and rings
		Adding Ground planes to Routing layers
	Example 3. Multipage, multipower, and multiground mixed A/D printed circuit board design with PSpice
		Introduction
		Multiplane layer methodologies
		Capture project setup for PSpice simulation and board design
			Adding schematic pages to the design
			Using off-Page connectors with wires
			Using off-page connectors with buses
			Setting up multiple ground systems on the schematic
			Setting up PSpice sources
			Performing PSpice simulations
		Designing the board with PCB Editor
			Create the board outline
			Placing parts on the bottom (back) of a board
			Layer stack-up for a multiground system
			Adding copper to the planes
			Establishing net, plane, and constraint relationships
			Defining blind vias
			Basic overview of using Padstack Editor
		Assigning vias to nets
			Assigning nets to layers using custom, physical constraints
			Fan-outs using blind vias
		Alternate methods of connecting separate Ground planes
			Shorting the planes with copper etch
			Shorting the planes with a Padstack
	Example 4. High-speed digital design
		Layer setup for microstrip transmission lines
		Constructing a heat spreader with copper pours and vias
			Via design for heat spreaders
		Determining critical trace length of transmission lines
			Routing controlled impedance traces
			Maximum neck length
		Moated ground areas for clock circuits
			Routing curved traces
		Gate and pin swapping
		Using swap options
			Pin swapping
			Function (gate) swapping
			Back Annotating the swap operations to Capture
		Using the Autoswap option
			Autoswapping an entire design
			Autoswapping a Room
			Autoswapping a window selection
			Viewing the swap list and the swap log
			Defining a route keep-out area
	Positive planes
		Positive plane artwork production
		Positive versus negative plane file sizes
		Pros and cons of using positive versus negative planes
	Design templates
		Making a custom Capture template
		Making a custom PCB Editor board template
		Making a custom PCB Editor technology template
	Using the board wizard
	Moving on to manufacturing
	References
	Further reading
10 Artwork development and board fabrication
	Schematic design in Capture
	The board design with PCB Editor
		Routing the board
		Placing mechanical symbols
			Mechanical symbols for mounting holes
			Mechanical symbols for fiducials
		Generating manufacturing data
			Generating the artwork
			Adding a photoplot outline
			Optional artwork items
		Generating the artwork files
			Artwork control form
			General parameters
			Film control
			Adding elements to the artwork control form
		Generating drill files
			Drill file format
			Manually generating a tool list
		Generating route path files
			Establishing an NC route tool list file
			Cut marks
			Drawing the cut path
		Generating the route file
		Verifying the artwork
	Using CAD tools to 3D model the printed circuit board design
	Fabricating the board
		Fabricated PCB inspection and testing
	Generating pick and place files
	References
11 Component information system
	Introduction
	Properties in component information system
		Reserved properties
		Transfer component information system properties to PCB Editor
	Component information system administration
		Database systems
		Connection of database and component information system
		The settings file CAPTURE.INI
		The database configuration file
			Database configuration file—Part Database tab
			Database configuration file—Administrative Preferences tab
			Database configuration file—Relational Database tab
	Component information system and PSpice
		Ideal R, L, and C
		C and L with parasitics
		Association of schematic part with PSpice model
		Homogeneous parts and PSpice
		Heterogeneous parts and PSpice
		Schematic parts with more pins than the PSpice model
		How to simulate a project designed for both printed circuit board design and simulation?
	Working with component information system
		Find and place parts
	Part Manager
		Customize Part Manager
		Part Manager features
	Bill of materials
	Variants
12 Signal integrity simulation with OrCAD
	What is signal integrity?
	How to simulate in OrCAD Signal Explorer
		Prelayout simulation
		Postlayout simulation (verification)
	How to use OrCAD PCB SI tool
		Getting started
		Scheduling a topology
	Electrical rule checks in OrCAD Sigrity ERC
		Setup
		Graphical reports
Appendix A List of design standards
	ANSI standards
	ASME standards
	IEEE standards
	IPC standards
	JEDEC standards
	Military standards
Appendix B Partial list of packages and footprints and some of the footprints included in OrCAD PCB Editor
Appendix C Rise and fall times for various logic families
Appendix D Drill and screw dimensions
Appendix E References by subject
	Component package types and mounting (surface-mounted device)
	Component placement, spacing, and orientation
		General considerations
		Capacitors/Bypassing/Placement
		Fiducials
		Wave soldering considerations
		Design rule checking
	Land patterns (footprint design)
		Surface-mounted device
		Through-hole
	Layer stack-ups
	Lead relationships
		Lead-to-hole ratio
		Lead bend radius and spacing
	Materials
		Copper
		Prepreg/Laminate
		Plating
		Solder
		Dielectric (relative permittivity) properties
	Mounting hardware and specifications
	PCB
		Fabrication
		Fabrication allowances
		Borders
		General design information
		Performance classes
		Assembly types
		Density levels
		Producibility levels
		Power distribution concepts
		Sizes/Panels
		Testing
	Plated through holes
		Types: Through, blind, buried, mounting holes
		Fabrication of through holes
		Aspect ratio
		Lead-to-hole ratio
		Hole-to-land ratio
		Land requirements
		Annular ring requirements
		Clearance from planes
		Nonfunctional lands
		Unsupported holes
		Fan-outs
		Via (through-hole) guidelines and fabrication
		Filled/Plugged holes
	Rise and fall times of logic families
	Schematics
		Symbols
		Diagrams
	Signal integrity
		Cross talk
		Ground bounce/rail collapse
		Propagation speed/time delay
		Reflections/Ringing
		Guard rings and traces
		Terminations
		Ground areas (split planes, moated grounds)
		Guard shields
		Noise reduction (general)
	EMI/EMC
	Soldering and assembly
		Assembly issues and processes
		Reflow soldering
		Wave soldering
		Components, placing/spacing
		Components, orientation
		Components, mounting
		Reliability
	Thermal management
	Trace routing
		Trace spacing (voltage withstanding)
		Trace spacing (cross talk/3-W rule)
		Trace width—current handling
		Trace width—transmission lines
		Microstrip
		Embedded microstrip
		Stripline
		Asymmetric stripline
	Transmission lines
		Characteristic impedance (microstrip, stripline topologies, etc.)
		Critical length
		Propagation delay time
		Reflections/Impedance mismatches
		Sharp corners
Index
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