Designing for Reuse in Altium Designer

Parent page: More about Schematics

The term 'Design Reuse' has become something of a cliche in the marketing of engineering products, perhaps primarily driven by how little of this actually happens. The same design task is performed over and over. However in electronics design, design reuse is practiced every day by every engineer using off-the-shelf integrated circuits. These devices are a package of electronics that someone, somewhere has designed, tested, documented and sold to the world at large. Every customer of this device is reusing this design in a very rigorous way.

In comparison, the real practice of design reuse in the rest of the design process is generally very poor and most likely consists of a variety of glorified copy and paste tools. Altium Designer offers a variety of solutions in support of design reuse, facilitating streamlined design without the need to reinvent the wheel.

Managed Schematic Sheets

Related page: Managed Schematic Sheets

Being able to re-use design content is something that all product development companies want, and can greatly benefit from. Not only does reuse save time, being able to easily re-use a section of a previous design means that all the qualification and testing of that part of the design is done. Design reuse is much more than copy and paste though, true reuse requires the content to be locked down so you're guaranteed that it is the same as before. No quick edits to change the color of a component or a tweak to a resistor value, working with reusable content must be like working with off-the-shelf components; place the content, wire it in, and it works just like it did last time.

Altium Designer, in conjunction with your managed content server, caters for the ability to create Managed Schematic Sheet Items in that Server. Such Items are created directly from within the Server. Once a Managed Schematic Sheet Item has been created (and data released into a revision of it), and its lifecycle state set to a level that the organization views as ready for use at the design level, it can be reused in future board-level design projects.

Formally release a sheet of design circuitry that can then be re-used - as a revision of a Managed Schematic Sheet Item - in other design projects requiring that same functionality.

A Managed Sheet is a standard Altium Designer schematic sheet containing components and wiring, that has been stored in a managed content server, so it can be re-used in other designs. It is edited like any other schematic sheet. The Managed Sheet concept is not limited to a single schematic sheet either, you can place a Managed Sheet in your design that is the top of a tree of other Managed Sheets.

The decision to move from Device Sheets to Managed Sheets comes when there is a desire to make the transition from re-useable content to managed re-useable content - that is, when there is a desire or need to be able to control the release, revision status and lifecycle state of that design content.

By making it managed content you can be sure that the revision of a Managed Sheet that you use in a design can be easily identified and traced back to its source whenever needed. And because it is managed content it can be revised and updated when needed; and the usage relationships can all be traced, both down to the components on that sheet, and up to the designs that use that sheet. This ensures you have all the information needed to decide if that revised sheet must be pushed through to existing designs, or if a particular design must continue to use the previous revision.

Device Sheets

Related page: Device Sheets

Device Sheets simplify the design process by providing modularized and consistent building blocks which can be re-used between projects. Device Sheet Symbols are placed and referenced similarly to components. They function in the same way as Sheet Symbols and Schematic Documents, but are not explicitly added to projects.

Device Sheets are stored as normal Schematic Documents in special Device Sheet Folders. They are placed and referenced in your project, similarly to a simple component. When the project is compiled, Device Sheets are included in the project hierarchy and are distinguished from standard Schematic Documents by a different icon in the Projects panel.

Example of a Read-only Device Sheet. There is also a Read Only watermark with a Device Sheet (recycle) watermark. The sheet itself is resident in a Device Sheet folder on the
local (or network) drive, and is included into a project (referenced) through placement and definition of a Device Sheet symbol on the parent sheet above.

Design Snippets

Related page: Snippets Panel

If your designs often include common 'sections' of circuitry, then you will make good use of the Design Snippets feature. A simple and easy to use feature, the Snippets system lets you save any selection of:

• Circuitry on a single schematic sheet.
• Circuitry in a PCB design, including the components and the routing.

A circuit 'snippet' can be added into any design, without you having to start from scratch each time - design reuse, made simple.

The Snippets panel is the central point for creating, managing, and reusing snippets of
design circuitry.