PCB Design Blogs

PSpice® A/D is a fully featured analog and mixed-signal simulator that can be integrated with OrCAD® and Allegro® tools. With PSpice A/D you can improve design functionality and reliability, and also verify the electrical performance of design components, such as filters, amplifiers, linear, and switched-mode power supplies.

It allows you to explore and test designs ranging from high-frequency systems to low-power ICs. Not just that, you can perform rigorous verification and analysis checks on linear and mixed-signal designs. 

PSpice A/D offers three main types of analyses for testing the circuit response to different inputs.

• AC analyses for a small-signal alternating source
• DC analyses for evaluating circuit performance in response to DC value of a signal in static conditions
• Transient (time-based) analyses for evaluating circuit performance in response to time-varying sources

To simulate a design, the PSpice A/D simulator needs information about circuit topology, analysis type, and stimulus definitions. The analysis type, stimulus definition, and the information related to the initial digital state of the simulation are provided by a Simulation Profile (*.SIM). Any number of simulation profiles can be specified for a project.

This blog post walks you through the basics of using PSpice A/D from an OrCAD Capture design.

Creating a PSpice A/D Project

To simulate an OrCAD Capture project in PSpice A/D, ensure that Enable PSpice Simulation is selected during the project creation phase. This opens a workspace where you can create your schematic and run PSpice A/D simulations.

	While creating a project, you either choose a blank project or base your new project on an existing PSpice A/D project. Sample projects are shipped with the installation, and you can use one of these to start your schematic design.

Adding Components to the Schematic Design

To place PSpice A/D components:

• From existing PSpice A/D libraries use, PSpice Part Search
• Generate your own component models from datasheets, using Modeling Applications

PSpice Part Search allows you to view all PSpice A/D parts at one place with respect to their function or library. You don’t have to remember which PSpice A/D library contains a specific model.

	For example, to create a circuit of a common-emitter amplifier, simply launch PSpice Part Search, specify a search string, and place the required part from the search results. The search string can be a model number or any other relevant part information. You can also browse through the Categories to find the required part.

To generate a custom model, use PSpice A/D Modeling Applications for the required device type, specify the parameter value from the datasheet, and place the schematic component associated with the newly generated model, without having to get out of the schematic entry interface of OrCAD Capture.

	Using the modeling applications, you can generate models for devices such as voltage sources, current sources, transformers, switches, VCOs, diodes, and passives. All you need to do is enter the device parameters which are listed and explained in the modeling application interface.

Completing the Schematic Design

Once you have placed all the components, complete the design connectivity by adding wires.

Simulating the Design

To simulate a design, first create a simulation profile by specifying information about the analysis type, stimulus definition, and the information related to the initial digital state of the simulation.

	Click the New Simulation Profile icon on the PSpice toolbar and specify the name of the simulation profile. In the Simulation Settings dialog box, select Analysis Type, and specify the related settings.

PSpice A/D provides support for multiple simulation profiles in a design. For each analysis type, you can create a separate profile. These simulation profiles are available from the PSpice toolbar and project manager pane. Select the required profile and run the simulation.

After simulating your design, PSpice A/D displays the waveform results so you can visualize the circuit behavior and determine the validity of your design. The waveform analysis features of PSpice A/D enables you to visually analyze and interactively manipulate the waveform data produced by the simulator.

In the PSpice A/D workspace, waveforms appear as plots, which are displayed in the output window. For PSpice A/D to display these output waveforms, you need to place markers in your circuit design in OrCAD Capture to indicate the points for which the simulation waveforms are to be generated.

	Add voltage markers to the circuit to plot the output and input voltage waveforms, and then run the simulation.

Waveforms are displayed corresponding to where the markers are placed on the schematic. With waveform analysis, you can, not just display simple voltages, currents, power, and noise data, but also display complex arithmetic expressions that use the basic measurements.

	To enable cursors in PSpice A/D, click the toggle on and off icon. You can also edit the current simulation setup from the PSpice A/D interface and rerun the simulation with the new settings.

If you find these steps simple, try a PSpice A/D simulation walkthrough at Cadence Online Support. You can access various demos on schematic design creation and learn how this process is integrated with PSpice A/D. You can also sign up for training on Analog Simulation with PSpice.