News and New Products

Defining "reference design"

By Nicholas Cravotta, Contributing Technical Editor -- EDN, 11/8/2007

The term "reference design" can apply to a wide range of materials available to educate engineers and accelerate design cycles. Definitions of some of the terms surrounding reference designs follow:

Data sheet: A data sheet describes the specifications of a component. Although essential, data sheets typically represent theoretical or projected limits whose accuracy varies upon many real-world factors.

Application note or white paper: Transferring IP (intellectual property) using an application note or white paper is attractive because companies can produce these publications without completely engineering a design. They can discuss concepts and show block diagrams. They are worth more when you can map them to a development board.

Virtual reference design: With these designs, rather than receive a board, developers have access to a schematic and list of recommendations. Virtual materials are appealing because anyone can download a file, and manufacturing limits the number of hardware boards that are available.

Demo board: The demo board is primarily a vehicle for powering up a device and exploring the first level of its capabilities. It usually has just enough components to turn on the device and communicate with it. Imagine considering the purchase of a car: You could look at the engine and kick the tires but could not take the car out of the lot.

Evaluation platform: To evaluate a component requires the ability to use and stress all or most of its features. Typically, evaluation boards or modules have additional support circuitry and limited software to enable testing of all modes of operation in a fashion that is close to but not the same as it would be in a real-world application. If the user is not going to use certain features or modes, you can remove some of this circuitry. If this product were a car, you’d be driving it around the block.

Web bench: This relatively new design-and-marketing tool provides a modeling environment in which developers can test component configurations. Engineers have access to hosted simulation environments or an evaluation board that they can easily configure and access through the Internet. Web benches can "demonstrate" the abilities of a component and provide fairly specific information about how to configure and program the device; engineers can then use this information to produce a production design. Evaluation through a Web bench is also more accessible to many engineers because it takes only a few minutes to see whether you want to explore further. Compare this approach with a hardware-based board, which may require hours to set up and configure.

Reference system: This system is a complete working system that enables real-world operation, testing, and stressing of the components used in the design. Full reference manuals, application software, and demos that illustrate the performance of the system in the best possible light are usually available. Often, you can get a complete schematic, although manufacturers assume no liability for any errors in the design. If this were a car, you’d be taking it home for a month and fiddling under the hood.

Production-ready design: This type of reference design shows how the component solves a problem. You use it as the foundation for final product design. If it were a car, all you’d change is the nameplate and the available colors.