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Seamless Schematic Simulation with OrCAD X and PSpice

Key Takeaways

  • Using schematic simulation reduces costly errors, accelerates time-to-market, and enhances overall design performance.

  • With tools for analog, digital, and mixed-signal simulations, OrCAD X ensures reliability across diverse circuit designs.

  • PSpice test benches allow designers to isolate critical sections of large circuits for focused analysis and optimization.

Creating a new simulation in PSpice from a schematic

Creating a new simulation in PSpice from a schematic

Schematic simulation bridges the gap between theoretical design and real-world functionality. It allows you to virtually test and validate your circuit designs under various conditions, minimizing errors and revisions in the design process. Without schematic simulation, you might face issues like signal integrity problems, excessive noise, or thermal overload—all of which can lead to product failures. 

To make the most of schematic simulation OrCAD X and PSpice step in. OrCAD X, bundled with PSpice simulation software, provides an integrated environment to analyze, optimize, and perfect your circuit designs before moving to production. Let’s explore how OrCAD X makes schematic simulation seamless.

PSpice Bundled with OrCAD X Enables Schematic Simulation

OrCAD X platform is an advanced PCB design software that integrates schematic capture, simulation, and layout into one comprehensive solution. Its PSpice simulation engine, advanced mixed-signal analysis tools, and extensive library of components empower designers to achieve simulation precision. Whether you're working on analog, digital, or mixed-signal designs, OrCAD X offers the tools to innovate and optimize at scale.

Step-by-Step Guide to General Circuit Simulation in PSpice

Step

Details

1. Create a PSpice Design

- Open OrCAD Capture.
- Select New Project from the start page or File > New Project.
- Name your project (e.g., "project_pspice").
- Check the box Enable PSpice Simulation.
- Select Blank Project and click OK.
- The schematic page launches. Ensure basic page setup (e.g., grid spacing, title block) is completed before proceeding.

2. Place Components

- Open the Place menu and navigate to PSpice Component > Diode to add components.
- Similarly, add other parts like inductors, capacitors, and resistors.
- For MOSFETs, use PSpice Component Search and type .
- Double-click the desired MOSFET in the search results to place it on the schematic.

3. Add Voltage Sources and Ground

- Go to PSpice Components > Modeling Applications.
- Add an independent voltage source under the Pulse tab. Configure parameters such as amplitude and duration for the waveform.
- Add ground using PSpice Component > Ground from the submenu.
- Arrange all components in the desired layout and edit component values as necessary.

4. Wire the Circuit

- Select the Wire icon from the toolbar.
- Connect all components by drawing wires between their corresponding pins.
- Save your design after completing the wiring.

5. Set Up Simulation Profile

- Navigate to PSpice > New Simulation Profile.
- Enter a profile name (e.g., "sim1") and click Create.
- In the simulation settings, select the type of analysis.
- For this example we’ll do Time Domain Analysis, with run time of 5 ms and a start time of 0 ms.
- Click OK to save the simulation settings.

6. Add Markers and Run Simulation

- Place voltage markers on the schematic at key points (e.g., DC voltage source, load resistor).
- Select PSpice > Run or the Run button in the toolbar to begin the simulation.

7. Analyze Results

- In the simulation graph, observe the red waveform (output voltage) and green waveform (input voltage).
- To analyze current levels, replace voltage markers with current markers and re-run the simulation.
- Review the current and voltage behavior

PSpice also enables digital logic simulations

PSpice also enables digital logic simulations

PSpice Enables Digital Schematic Simulation 

PSpice allows for the simulation of digital circuits, such as counters, to ensure that their logic and behavior meet design requirements before implementation. This section overviews key capabilities and steps to create and simulate an 8-bit counter circuit.

  • Component Placement: Supports digital ICs, pull-ups, pull-downs, and clock sources, enabling accurate modeling of digital logic circuits.

  • Stimulus Configuration: Allows configuring digital stimuli (e.g., clocks) with specific frequency and duty cycle to drive the circuit.

  • Gate-Level Simulation: Enables transient analysis and gate-level state configuration for precise simulation of digital logic behavior.

  • Visualization: Provides trace analysis for viewing the outputs of multiple states, aiding in validation of the circuit's functionality.

OrCAD X Digital Schematic Simulation Steps

Step

Details

Create a New Project

- Launch OrCAD Capture.
- Select File > New Project.
- Name the project (e.g., "counter") and choose Enable PSpice Simulation.
- Save the project in a new folder.

Place Digital Components

- Add pull-ups and pull-downs using the Place > Component menu.
- Place the digital ICs and wire them up as needed.
- Include a digital clock source as a driver.

Configure the Digital Stimulus

- Right-click the digital clock source and select Edit Stimulus.
- Set the name, frequency (e.g., 100 Hz), and duty cycle (e.g., 50%).
- Save the stimulus configuration.

Complete the Circuit Design

- Wire the pull-ups, pull-downs, clock source, and counter ICs.
- Ensure proper connections between inputs and outputs.
- Save the completed schematic.

Set Up Simulation Profile

- Click Create New Simulation Profile.
- Name the profile and select Transient Analysis (Time Domain).
- Set the run time to 5 seconds.

Configure Gate-Level Settings

- In the simulation profile, navigate to Options > Gate-Level Simulation.
- Set the Digital Integer State option to zero for initialization.
- Save and close the settings.

Run the Schematic Simulation

- Select PSpice > Run to perform the simulation.
- View the output waveforms in the simulation results window.

Add and Analyze Traces

- Use the Add Trace button to select outputs (e.g., QA, QB, QC, QD) of both counter ICs.
- Zoom in on specific sections to verify logic transitions and behavior.

Save the Project

- Save the project and results for future reference or documentation.

Arbitrary example circuit and associated simulation testbench results in OrCAD X PSpice.

Arbitrary example circuit and associated simulation testbench results in OrCAD X PSpice. 

Simulating Sections of Complex Designs with Test Benches

When working on complex schematics, simulating the entire circuit can be time-consuming and resource-intensive. PSpice offers a powerful feature called test benches, which allows designers to focus on critical sections of their schematic for targeted analysis. 

This approach streamlines the simulation process, enabling faster validation and optimization of key components without the need to configure the entire design.

  • Test benches in PSpice let you isolate specific parts of a circuit, such as a boost converter or control module, and simulate them independently. 

  • By enabling only the relevant components, handling floating nets, and defining targeted simulation profiles, you can efficiently analyze functionality within a controlled environment

  • This capability saves time and reduces complexity, making it ideal for optimizing subsystems in larger designs.

Why OrCAD X With PSpice is Ideal for Schematic Simulation

OrCAD X with PSpice offers a comprehensive solution for schematic simulation. PSpice simulation engine supports both analog and mixed-signal analysis, allowing users to perform transient, DC sweep, AC sweep, and bias point simulations. Advanced features such as temperature sweeps, sensitivity analysis, and Monte Carlo analysis help refine designs, improve reliability, and reduce costs.

With access to over 33,000 simulation-ready models from leading IC vendors and wizard-based tools for custom component creation, PSpice simplifies even the most complex design tasks. Whether optimizing performance, analyzing trade-offs, or simulating multi-mode designs, OrCAD X with PSpice ensures seamless integration and accurate results. For engineers tackling high-performance and reliable designs, this combination is a trusted choice in the industry.

Schematic simulation is an important step in ensuring your circuit designs are optimized and reliable before manufacturing. Ready to enhance your design workflow? Explore Cadence’s PCB Design and Analysis Software to learn how OrCAD X can revolutionize your approach to schematic simulation. Dive into the possibilities with OrCAD X and achieve unparalleled accuracy in your PCB designs.

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