Convert SCH to DSN

A schematic saved as .sch may need conversion when OrCAD Capture or a related Cadence workflow requires an OrCAD .dsn design. The correct method depends on the application that created the SCH file; changing its extension does not convert the internal format.

What the SCH format is

In electronic CAD, .sch is an ambiguous schematic extension used by several EDA programs. Common sources include legacy OrCAD SDT, older PSpice Schematics, KiCad, and other circuit-design applications. Engineers use these files to describe circuit connectivity and documentation.

An SCH file can contain symbols, wires, net names, reference designators, values, power symbols, buses, hierarchical connections, text, and page settings. Some formats store symbol definitions internally; others depend on separate libraries, project files, configuration data, or simulation properties. Confirm the creating application from the project documentation, file header, or the software that originally opened the file before selecting an importer.

What the DSN format is

.dsn is primarily an OrCAD Capture design file. It stores a Capture schematic design and its hierarchical pages; it is not a universal schematic-exchange format. An OrCAD project normally also includes related files such as an .opj project file, libraries, configuration data, and possibly CIS database information.

DSN is appropriate when the destination uses OrCAD Capture or Capture CIS for schematic editing, annotation, electrical-rule checking, bill-of-materials generation, simulation integration, or netlist output. It is not inherently smaller, more portable, or more complete than SCH, and it does not guarantee that the source application's symbols and electrical properties will transfer.

How to convert SCH to DSN

1. Make a working copy of the SCH file. Collect the source project's symbol libraries, configuration files, simulation data, and any related project files before starting.
2. Identify the source format. An OrCAD SDT SCH file is the most direct candidate for Capture's legacy SDT importer. An SCH from KiCad, Altium, PSpice Schematics, or another EDA application must use that application's supported export or migration route instead.
3. Install and open a compatible version of Cadence OrCAD Capture. In Capture, use File → Import Design and select the importer for OrCAD SDT, or the exact legacy format identified in the previous step. Menu names and supported translators vary by Capture release.
4. Select the source .sch, destination folder, and any required symbol-library locations. Run the import and save the resulting design as an OrCAD Capture .dsn using File → Save As. Keep the generated DSN, project file, libraries, and configuration files together.
5. Read the import log before editing the result. Resolve missing libraries, unsupported objects, duplicate references, and electrical-rule warnings rather than assuming that a successful import means a complete conversion.
6. Inspect every page and verify symbol graphics, pin numbers, reference designators, net names, wire junctions, buses, hierarchical ports, power symbols, hidden pins, and text. Run annotation and electrical-rule checks only after confirming connectivity.

For an SCH created by PSpice Schematics, use the PSpice-to-Capture migration utility supplied with the applicable OrCAD release, if that release provides one. For KiCad, Altium, or another source system, open the design in the original software and export a format that the target Capture version explicitly supports, such as an agreed EDIF variant where both applications provide compatible import and export. An exported PDF or image preserves appearance only and cannot create an editable DSN.

Generic online converters such as file-format websites are not a suitable replacement for an EDA importer: they generally cannot preserve symbol libraries, hierarchical structure, pin properties, simulation data, or electrical connectivity. No widely applicable browser service reliably converts proprietary SCH designs to native OrCAD DSN. Avoid uploading confidential circuit designs to an online service unless its supported source format, output structure, and data-handling terms are verified.

Quality and compatibility limitations

Renaming board.sch to board.dsn changes only the filename. The internal file remains an SCH database, so Capture will normally reject it or open an unusable design.

Legacy translators can change fonts, page borders, graphical annotations, custom symbols, hidden pins, simulation properties, hierarchical references, library links, and unsupported attributes. A page that looks correct does not prove that its net connectivity or pin mapping is correct. Compare the imported netlist with a netlist generated from the source design before using the result for PCB layout, simulation, or manufacturing.

Capture versions also have compatibility limits. Save and test the DSN in the exact Capture release and downstream workflow that will use it. Retain the original SCH, source libraries, import log, generated project files, and a PDF or plotted copy for archival comparison.