Circuit Simulation and PCB Design Software

Key Takeaways

• From concept to manufacturing, circuit simulation plays a critical role in verifying functionality and performance.

• Cadence PSpice and OrCAD X Capture offer a seamless environment for designing, simulating, and optimizing electronic circuits.

• PSpice provides comprehensive analysis capabilities, including DC, AC, transient, and Monte Carlo simulations.

Circuit simulation and PCB design software play complementary roles in the PCB design process. They provide engineers with tools for designing, simulating, verifying, and optimizing electronic circuits. During the PCB design process, they collaborate to ensure the circuit's functionality and performance.  

PSpice Enables Collaboration of Circuit Simulation and PCB Design

The PSpice simulation tool and OrCAD X PCB design software provide powerful solutions for designing and simulating electronic circuits and PCBs.

PSpice is a powerful circuit simulation tool that allows engineers to simulate the behavior of electronic circuits before prototyping or production, enabling thorough analysis and optimization.  Engineers can design circuits in OrCAD X Capture (the schematic editor) and use the same circuit to develop their board layout directly simulate in PSPICE without requiring manual translation or conversion of design files.

Once a PCB circuit design is simulated, engineers can analyze the results and make design modifications as needed in OrCAD X, maintaining a synchronized workflow between design and simulation. Changes to the schematic in OrCAD X are automatically reflected in the PSpice simulation, ensuring consistency throughout the design process.

Where Does Circuit Simulation Take Place in the PCB Design Process

Circuit Simulation and PCB Design Concept and Specifications

Early in the concept phase, engineers define high-level functional blocks, set power and performance targets, and choose initial components. Decisions made here shape everything downstream. To guard against these risks, validate your architectural choices as soon as they’re on the table. With those targets in mind, simulation becomes your first line of defense:

Simulation Role:

• Behavioral co-simulation: Combine analog and digital models to verify block-level functionality.

• Feasibility studies: Quickly benchmark candidate components against your power/performance targets.

• Preliminary SPICE-level models: Validate sensitive analog front-ends using vendor or custom subcircuit models.

Schematic Capture and Circuit Simulation

PSPICE covers all the basics and must-haves for schematic simulation to validate your board such as:

• Transient analysis: Observe switching behavior, startup, and edge-rate effects.

• AC sweep: Characterize the frequency response of amplifiers, filters, and feedback loops.

• Parametric & corner tests: Explore part tolerances and temperature extremes.

Pre-Layout Simulation

After schematic capture, blocks such as high-speed buses, critical power rails, and precision analog paths should be validated. At this point, you also validate your power budget and establish baseline signal-quality metrics so that layout trade-offs stay within acceptable margins.

Simulation Role:

• Signal integrity: Generate eye diagrams and reflection plots for high-speed signals.

• Power integrity: Simulate voltage ripple, decoupling effectiveness, and plane impedance.

• EMC/EMI prediction: Incorporate parasitic elements to anticipate interference issues.

• Yield optimization: Run Monte Carlo and sensitivity sweeps to understand tolerance-driven variation.

Circuit Simulation and PCB Layout Design Compatibility

When entering the layout phase, physical constraints, such as board outlines, component placement, and routing channels, can clash with your electrical requirements. Crosstalk, impedance discontinuities, and return-path integrity become pressing concerns that static schematics simply cannot reveal. To bridge the gap between logical design and physical realization, post-layout simulation can be useful:

Simulation Role:

• Post-layout SI: Re-evaluate signal integrity with actual trace geometries, vias, and stubs.

• Post-layout PI: Analyze plane and decoupling performance using real copper pour shapes.

• Thermal simulation: Predict hotspots and verify heatsinking strategies.

• 3D field analysis: Validate RF and high-frequency behavior in multilayer structures.

Circuit Simulation Validates PCB Design Review and Sign-Off

By sign-off, you must prove your design meets functional, reliability, and regulatory standards under required operating conditions. Late-stage surprises (e.g., unexpected resonance in a power plane, margin erosion at temperature extremes) can trigger costly board respins. Final simulations tie everything together:

Simulation Role:

• Parasitic-extracted timing and SI/PI: Validate worst-case performance with real-world tolerances.

• EMC pre-certification: Run full-system EMI checks against target regulations.

• Reliability analysis: Employ Worst-Case Circuit Analysis (WCCA) to confirm robustness under aging, thermal cycling, and stress.

To effectively bridge circuit simulation and PCB design, Cadence offers integrated solutions that streamline your workflow. With robust PSpice simulation capabilities and advanced OrCAD X design features, engineers can confidently move from concept to production. Experience the synergy of these tools by exploring the OrCAD X platform and starting your free trial.