OrCAD vs. Allegro — Your Complete PCB Design & Layout Guide

 

Introduction

In the world of electronic design automation (EDA), two names stand out prominently: OrCAD and Allegro. Both are powerful suites of tools developed by Cadence Design Systems, catering to the complex needs of printed circuit board (PCB) design and layout. This comprehensive guide aims to explore the features, capabilities, and differences between OrCAD and Allegro, helping you make an informed decision for your PCB design needs.

Understanding OrCAD and Allegro

OrCAD: An Overview

OrCAD, short for Oregon Computer Aided Design, has been a staple in the PCB design industry since its inception in 1985. Acquired by Cadence Design Systems in 1999, OrCAD has evolved into a comprehensive suite of tools for schematic capture, PCB layout, and simulation.

Allegro: An Overview

Allegro, also developed by Cadence Design Systems, is a high-end PCB design platform known for its advanced capabilities in handling complex, high-speed designs. It offers a more extensive set of tools compared to OrCAD, catering to the needs of enterprise-level electronic design.

The Cadence Ecosystem

Both OrCAD and Allegro are part of the larger Cadence ecosystem, which allows for seamless integration and data flow between different design stages. This integration is a key factor in understanding the relationship between these two platforms.

OrCAD: Features and Capabilities

OrCAD Capture

OrCAD Capture is the schematic entry tool in the OrCAD suite. Key features include:

1. Intuitive user interface
2. Extensive component libraries
3. Hierarchical design capabilities
4. Design rule checking
5. Integration with simulation tools

OrCAD PCB Designer

OrCAD PCB Designer is the layout tool, offering:

1. Constraint-driven PCB layout
2. Interactive and autorouting capabilities
3. 3D visualization
4. Design for manufacturing (DFM) checks
5. Integration with mechanical CAD tools

OrCAD PSpice

For circuit simulation, OrCAD PSpice provides:

1. Analog and mixed-signal simulation
2. Extensive model libraries
3. Parametric analysis
4. Monte Carlo analysis
5. Temperature and stress analysis

Allegro: Features and Capabilities

Allegro Design Entry HDL

Allegro Design Entry HDL is the high-end schematic capture tool, offering:

1. Advanced constraint management
2. Team design capabilities
3. Integration with system-level design tools
4. Extensive library management features
5. Support for complex hierarchical designs

Allegro PCB Designer

Allegro PCB Designer is a powerful layout tool with features such as:

1. Advanced constraint-driven layout
2. High-speed design rules and analysis
3. Flex and rigid-flex PCB design capabilities
4. Advanced autorouting algorithms
5. Comprehensive signal integrity analysis

Allegro SiP Layout

For System-in-Package designs, Allegro SiP Layout offers:

1. Die stack planning and optimization
2. Wirebond and flip-chip support
3. 3D die and package visualization
4. Thermal and stress analysis
5. Integration with IC package design tools

Comparing OrCAD and Allegro

Feature Comparison

Feature
OrCAD
Allegro
Schematic Capture
OrCAD Capture
Allegro Design Entry HDL
PCB Layout
OrCAD PCB Designer
Allegro PCB Designer
Simulation
OrCAD PSpice
Allegro AMS Simulator
High-Speed Design
Limited capabilities
Advanced features
Flex PCB Design
Basic support
Advanced support
Team Collaboration
Limited
Extensive
Cost
Lower
Higher
Learning Curve
Moderate
Steep
Target Users
Small to medium businesses, individual designers
Large enterprises, complex designs

Schematic Capture: OrCAD Capture vs. Allegro Design Entry HDL

OrCAD Capture

1. User-friendly interface
2. Suitable for small to medium-sized projects
3. Basic hierarchical design capabilities
4. Integration with OrCAD PCB Designer

Allegro Design Entry HDL

1. Advanced constraint management
2. Better suited for large, complex designs
3. Enhanced team design features
4. Tighter integration with system-level design tools

PCB Layout: OrCAD PCB Designer vs. Allegro PCB Designer

OrCAD PCB Designer

1. Constraint-driven design
2. Interactive and auto-routing
3. Basic high-speed design capabilities
4. 3D visualization

Allegro PCB Designer

1. Advanced constraint management
2. Superior high-speed design tools
3. Flex and rigid-flex PCB design
4. Enhanced signal integrity analysis
5. Advanced team design features

Simulation: OrCAD PSpice vs. Allegro AMS Simulator

OrCAD PSpice

1. Analog and mixed-signal simulation
2. Extensive component libraries
3. Basic parametric and Monte Carlo analysis

Allegro AMS Simulator

1. Advanced mixed-signal simulation
2. Integration with RF and high-speed design tools
3. Enhanced parametric and statistical analysis

Choosing Between OrCAD and Allegro

Factors to Consider

1. Project complexity
2. Team size and collaboration needs
3. High-speed design requirements
4. Budget constraints
5. Learning curve and training requirements
6. Integration with other design tools
7. Future scalability needs

Scenarios for Choosing OrCAD

1. Small to medium-sized businesses
2. Individual designers or small teams
3. Projects with moderate complexity
4. Limited budget for EDA tools
5. Need for a shorter learning curve

Scenarios for Choosing Allegro

1. Large enterprises
2. Complex, high-speed designs
3. Advanced PCB technologies (e.g., flex, rigid-flex)
4. Extensive team collaboration requirements
5. Integration with IC and package design workflows
6. Need for advanced signal integrity and power integrity analysis

Transitioning from OrCAD to Allegro

Reasons for Transitioning

1. Increasing design complexity
2. Growing team size
3. Need for advanced high-speed design capabilities
4. Requirement for better team collaboration tools
5. Integration with broader IC and system-level design flows

Transition Process

1. Assessing current design workflows
2. Identifying gaps in capabilities
3. Training team members on Allegro
4. Gradual migration of projects
5. Establishing new design processes and best practices

Challenges in Transition

1. Steeper learning curve for Allegro
2. Potential disruption to ongoing projects
3. Higher licensing costs
4. Need for more powerful hardware
5. Adapting to new design methodologies

Best Practices for PCB Design with OrCAD and Allegro

General PCB Design Best Practices

1. Establish clear design requirements and constraints
2. Use hierarchical design methodologies for complex projects
3. Implement robust version control and data management
4. Conduct regular design reviews
5. Utilize design rule checks (DRCs) throughout the design process

OrCAD-Specific Best Practices

1. Leverage OrCAD Capture's symbol and footprint wizards for custom components
2. Utilize PSpice for pre-layout simulation to catch electrical issues early
3. Take advantage of OrCAD PCB Designer's constraint manager for design rules
4. Use the 3D viewer for mechanical clearance checks
5. Implement DFM checks before finalizing the design

Allegro-Specific Best Practices

1. Utilize Allegro's advanced constraint management for high-speed designs
2. Leverage the team design features for large, collaborative projects
3. Use Allegro's signal integrity tools for critical high-speed interfaces
4. Implement Allegro's power integrity analysis for complex power distribution networks
5. Take advantage of Allegro's advanced autorouting capabilities for initial placement optimization

Industry Applications and Case Studies

OrCAD Success Stories

1. Consumer Electronics: A startup using OrCAD to design a new smart home device
2. Automotive: Mid-size company developing automotive sensors with OrCAD
3. Industrial Automation: Small team designing PLCs using OrCAD suite

Allegro in Action

1. Telecommunications: Large corporation designing 5G infrastructure equipment
2. Aerospace: Defense contractor developing avionics systems
3. High-Performance Computing: Tech giant creating next-generation server boards

Future Trends in PCB Design and EDA Tools

Artificial Intelligence and Machine Learning

1. AI-assisted component placement and routing
2. Machine learning for design rule optimization
3. Predictive analysis for signal and power integrity

Cloud-Based Design Collaboration

1. Real-time collaborative design environments
2. Cloud-based simulation and analysis
3. Integration with PLM and supply chain management systems

Integration with Additive Manufacturing

1. Support for 3D-printed electronics
2. Design tools for conformal and flexible PCBs
3. Integration with 3D printing workflows

Enhanced Simulation and Digital Twins

1. More accurate and faster electromagnetic simulations
2. Integration of thermal and mechanical simulations
3. Creation of digital twins for virtual prototyping

Increased Automation in Design Flow

1. Automated design rule generation based on manufacturing capabilities
2. Intelligent autorouting and auto-placement algorithms
3. Automated design optimization for performance and manufacturability

Cost Considerations: OrCAD vs. Allegro

Licensing Models

1. Perpetual licenses
2. Subscription-based models
3. Token-based licensing for flexible usage

Total Cost of Ownership

Cost Factor
OrCAD
Allegro
Initial License Cost
Lower
Higher
Annual Maintenance
Moderate
Higher
Training Costs
Moderate
Significant
Hardware Requirements
Standard
High-performance
Productivity Gains
Good
Excellent for complex designs

Return on Investment (ROI) Considerations

1. Time-to-market improvements
2. Reduction in design iterations
3. Capability to handle more complex projects
4. Team productivity enhancements
5. Integration with existing design flows

Training and Resources

OrCAD Training Options

1. Online tutorials and webinars
2. Cadence Training Services
3. Third-party training providers
4. User community forums and resources

Allegro Training Options

1. Comprehensive Cadence instructor-led courses
2. Advanced online training modules
3. Customized on-site training for enterprises
4. Extensive documentation and application notes

Continuous Learning and Skill Development

1. Attending industry conferences and seminars
2. Participating in user groups and forums
3. Keeping up with Cadence product updates and roadmaps
4. Exploring complementary technologies and design methodologies

Frequently Asked Questions (FAQ)

1. Q: Can I use OrCAD and Allegro together in my design workflow? A: Yes, OrCAD and Allegro are part of the Cadence ecosystem and can be used together. Many organizations use OrCAD for initial schematic capture and basic PCB layout, then transition to Allegro for more complex routing and analysis. The data can be transferred between the two platforms, allowing for a seamless workflow from simple to complex designs.
2. Q: How do OrCAD and Allegro handle high-speed design requirements? A: While both tools offer high-speed design capabilities, Allegro is generally better equipped for complex high-speed designs. OrCAD provides basic high-speed design features suitable for many applications, but Allegro offers more advanced constraint management, signal integrity analysis, and power integrity tools. For designs with critical high-speed interfaces or complex timing requirements, Allegro is typically the preferred choice.
3. Q: What are the main differences in the user interface and learning curve between OrCAD and Allegro? A: OrCAD generally has a more intuitive user interface and a gentler learning curve, making it suitable for individual designers and smaller teams. Allegro, with its more extensive feature set, has a steeper learning curve and a more complex interface. However, this complexity allows for greater control and capability in handling large, complex designs. Training requirements are typically higher for Allegro compared to OrCAD.
4. Q: How do OrCAD and Allegro compare in terms of library management and component creation? A: Both OrCAD and Allegro offer robust library management features, but Allegro provides more advanced capabilities:
   • OrCAD: Offers good library management with symbol and footprint creation tools, suitable for most standard designs.
   • Allegro: Provides enhanced library management with advanced symbol and footprint generators, better support for complex component types, and improved team library sharing features.
5. Q: Can OrCAD handle flex and rigid-flex PCB designs, or is Allegro required for these technologies? A: While OrCAD PCB Designer does offer some basic support for flex and rigid-flex PCB designs, Allegro PCB Designer is better equipped for these technologies. Allegro provides advanced tools specifically designed for flex and rigid-flex boards, including specialized layer stack-up definitions, bend area design rules, and 3D visualization of flex assemblies. For complex flex or rigid-flex designs, Allegro is generally the recommended choice.