Providing references: supporting the engineer from prototype to production

At the same time, engineers face shorter design cycles. These factors, combined with budget constraints and other complexities, mean today's engineers need all the help they can get to bring their new product to market. One way in which they can do this is through the use of reference designs. But these mean different things to different companies, so how does Digi-Key define a reference design? In Digi-Key's view, a reference design is essentially a technical blueprint of a system which is made available to engineers as a guide or foundation for design. Typically, it will contain the basic elements of the system and is designed to act as a starting point for a specific product design. Engineers can then modify and personalise the circuit design as needed. While others may define a reference design as an end to end product design solution, Digi-Key has recognised the need to provide partial solutions that can meet common engineering needs. Based on customer interest and search patterns, Digi-Key offers full solutions such as a dc/ac inverter, led bulb driver or an ac/dc wall converter, while partial solutions address such areas as dc/dc conversion, audio amplifiers and motor drivers. The main purpose of a reference design is to speed the development of new products using latest technologies. Because engineers know they can start with a proven platform targeted for specific applications, they can shorten the design cycle, minimise errors and delays and get their product to market more quickly. Digi-Key's Reference Design Library is an interactive resource for design engineers seeking a specific circuit design for a particular project. Each reference design is a circuit providing a full or partial solution and which is proven and in use. Digi-Key's library differs from other offerings in that it allows searching and filtering based on the product design's measured performance. The reference library was established several years ago, when its application engineers became intrigued with the increased number of reference designs from its suppliers, despite the customer's inability to search or shop for those reference designs by attributes. Responding to what was an unmet customer need, Digi-Key created a library of designs for engineers seeking specific solutions to their problems. The library: • saves time by cutting the number of steps in the design process • easy access to useful product ideas and design platforms • specific designs by category, supplier and performance • detailed schematics with each design Having dealt with engineers for many years, Digi-Key understands the product design process. It knows how important it is for engineers to have easy access to two things – parts and information. But, with vast amounts of knowledge and many thousands of parts, the key is making it easy for the engineer to find useful content and the right part quickly. The Reference Design Library is built on an interactive and powerful search engine that enables engineers to access designs quickly and easily by category and by keyword. It includes the following categories: • ac/dc and dc/dc conversion • audio amplifiers • energy harvesting, lighting • motor control, power management • sensor solutions • wired communication • wireless communication. The company's philosophy on reference designs follows its core business model, providing customers with the best possible service and supporting them from prototype to production. By organising designs so engineers can quickly locate a solution to use or modify, Digi-Key has developed a valuable tool that meets an important need. Digi-Key essentially offers its Intellectual Property in the rapid, easy access of hosted application notes and reference designs. By aggregating proven designs with measurable performance specifications, the company has created searchable, user friendly formats that appeal to time strapped engineers seeking shortcuts. Although a collection of reference designs is available online, Digi-Key's application engineers can also assist customers with their particular designs. The LM3406 LED driver board is one example of a reference design that has been modified by Digi-Key's application engineers and made public in response to customer interest and demand. One recent addition is the IPS-EVAL-EH-01 energy harvesting evaluation kit, which allows users to investigate how to store harvested energy efficiently. The kit is based around the Thinergy MEC201 Micro Energy Cell from Infinite Power Solutions. This is an energy storage device intended for use in deeply embedded applications that require the lowest cost of ownership and a battery that can accept minute amounts of harvested energy while lasting the lifetime of the application. The PCB assembly incorporates a Thinergy MEC201, the Maxim MAX17710 integrated power management ic for battery and load management and a Sanyo/Amorton amorphous silicon solar panel (see fig 1). The IPS-EVAL-EH-01 board can be easily connected to a target system, such as a microcontroller or wireless demonstration kit, to create a standalone system that does not require external power or replacement of batteries. The board provides a complete system for prototyping energy harvesting applications. The user can select one of several options as an energy harvesting source and can also configure the regulated output voltage for various applications. Schematic and Gerber files are available in the user guide supplied with the board. Another reference design example is the MCP73871 demo board with voltage proportional current control. This demonstrates the capabilities of Microchip's standalone linear Li-ion battery charger with system power path and load sharing management control. The MCP73871 integrates the elements necessary to meet the challenges designers face when developing products powered by Li-ion and Li-polymer batteries. The MCP73871 board is designed to deliver a minimum of 1.5A total current to the system load and to a single cell Li-ion battery at 4.2V (4.1V, 4.35V and 4.4V options are also available). The demo board has a dip switch with four poles to to control input current limits, enable charge timer and enable charging. The first switch decides the input power source between the ac/dc supply and the USB port. The second switch determines the 500mA high power USB port or the 100mA low power USB port if the first switch is enabled. The user guide includes a board schematic, as well as top silk and pads, top metal layer and bottom layer. A bill of materials is also provided. Typical applications for the reference design include handheld medical devices and portable communications products. Interest is growing Highlighting the growing popularity of the reference design amongst engineers, Digi-Key's Reference Design Library has seen traffic increasing by nearly 200% during the past year. Engineers need fast access to online resources to help them through the entire product design process. These resources will help them to reduce costs while accelerating product design cycle time, allowing them to get their new product to market faster than the competition. Brian German is a Digi-Key technician whose primary focus is on the Reference Design Library.