Developing a new and innovative device can be a difficult and costly process, especially when that device is connected and potentially a part of a complex and high-tech ecosystem. The resource requirements involved in the initial, up-front product development are only compounded by the costs of maintaining a product to keep it in the market, and the potential opportunity costs of failing to get the device to market and capturing market share.  There are two common approaches to navigating the initial stages of core system development for a device.  Both have their advantages and disadvantages, but it is up to each product OEM to decide which is best for them.

Two of the most common development methods when designing connected products are the chip-down and modular methods.  Chip-Down involves designing the whole system from scratch. The focus of this article is the Modular approach, which involves designing around a core system (or module) that is designed and maintained by an outside supplier. This allows the OEM to focus on designing their application-specific portion of the product.

The decision between modular and chip-down needs to happen early in the development process, but for some OEMs, the better option isn’t always clear. Chances are that the decision will need to factor in issues such as the time it takes to bring a product to market, regulatory requirements and certification, availability of software, and initial engineering costs.  Several additional issues may factor into the decision.

Modular Development 101

The modular approach starts with a development kit, plus a system on module (SOM).  The development kit provides the basic functionality shared by a variety of OEM customers but doesn’t include customer-specific features.  It does, however, give the OEM customer a quick idea of how the system could operate, and it can allow the OEM to choose and evaluate the performance of a given operating system.  Once the OS has been selected, the OEM software development can begin almost immediately because the development kit can usually provide a foundation for this work.

The parallel development of software and hardware afforded by choosing the modular approach can accelerate the product development timeline.  Hardware engineers can focus their attention on the design and development of the application-specific baseboard instead of reinventing the fundamentals like the processor and basic peripherals.  Once the OEM product is complete, the SOM is mated to the OEM’s baseboard to fit neatly into the case of the final product.

A modular approach can decrease the number of components that would need to be designed from scratch in a chip-down system.  This decreases the resource needs for the OEM to commit to design, shortens the time-to-market, cuts initial engineering costs, and reduces continuing/sustaining engineering resources required to keep the product viable.

Additional complexity can emerge when new devices will utilize wireless technologies like Bluetooth and WiFi as they represent separate technologies and necessities such as optimizing an RF circuit for radio transmission can be difficult and time-consuming. Purchasing a module pre-certified by the FCC and ISED allows an OEM designer who uses the reference design to bypass the extensive testing required for the system.  This saves the OEM initial development costs and reduces development time.  OEMs considering international distribution should also find RoHS and REACH-certified modules, and documentation for CE compliance for use in Europe.  Changes to regulatory rules are managed by the SOM manufacturer, and they should notify the OEM if these standards are changed in ways that impact the OEM.

Post-Launch Advantages

Once a new device is complete and in-field, maintenance costs also come into play. Some of these costs include managing component obsolescence, fixing software bugs and patching security holes.  Again, the modular approach can prove advantageous here as the continuing/sustaining engineering for the SOM is managed by its manufacturer, the OEM can focus on supporting their custom baseboard and other areas of their expertise.

Managing one SOM supplier can be less work than managing multiple suppliers for the multitude of parts that encompass the SOM.  Component obsolescence can be costly if a replacement component is not readily available or requires a software or board layout change.  Since the responsibility for assessing and addressing impact to critical components rests with the SOM manufacturer, the OEM is isolated from much of the minutiae involved with maintaining the SOM.  When components become obsolete, the SOM manufacturer will find a replacement, verify and validate the design and regulatory compliance, update the software, and if necessary, update the hardware design–all work that usually falls outside the obligations of the OEM.

Different module manufacturers cater to these different objectives, but when selecting a module, it’s important for the OEM to confirm the component’s life expectancy to plan for and mitigate unexpected changes.  Devices designed on commercial or retail components often have a short life cycle, so the OEM may experience frequent product changes requiring regular updates and testing.  An OEM requiring a long life span will certainly want to choose a company who will keep their product available long enough to meet their needs.  Modules from Compass Electronics Solutions target Medical and Aerospace OEMs, which are more likely to avoid obsolescence for 10-plus years and offer lower maintenance costs to the OEM when compared to a module with a shorter life or a higher frequency of changes.

Making the Core System Decision

The modular approach is not necessarily for everyone.  The decision between chip-down and a modular approach is heavily impacted by the projected quantity of units the OEM produce.  High-volume customers may find that the chip-down solution is a better solution since larger sales volumes can justify higher upfront costs and maintenance costs due to the overall economies of scale.  The threshold where the overall costs “cross-over” will vary for each OEM based on their market and expected margin (see graph below).

Each OEM needs to evaluate their expected sales volume; identify their expected margin; examine their risks for part obsolescence, software updates and security holes; and decide how urgently the product needs to come to market.  If that OEM can justify the time and costs development due to large volume, that OEM should choose the chip-down solution. For most OEM customers, however, the better decision may be going modular.

Adam Ford
Senior Applications Engineer

SOMs may be the smart choice for your connected device. View more reasons why to use System on Modules.

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