Bluetooth Low Energy (BLE) Designs - Chip or Module: Which is Best?
Wednesday, April 23, 2014
The wireless market is exploding with products based on Bluetooth Low Energy (BLE) technology. From location tags that help you find your keys to electronic credit cards to locks that open when you’re near. Ever since the Bluetooth Special Interest Group (SIG) added the Bluetooth Core Specification Version 4.0 in 2010, companies have been finding unique applications for BLE. Apple realized the value of these accessories and incorporated iBeacon into iOS7. With the increasing popularity of BLE-based products, we at Symmetry have been getting lots of questions about designing BLE into products.
What are the Benefits of BLE Designs?
So what makes BLE so attractive? It’s cheaper than Bluetooth Classic, runs for months on a small battery, and talks to your smartphone. As wonderful as BLE is, it’s also important to be aware of its limitations. The data rate is low - you can’t use it to stream high quality audio or surf the web. But if you’re building a sensor that reports back a few bytes of data every now and again, or a device that advertises services to all smartphones in the area, then BLE is the way to go.
Now that you’ve decided to design your own BLE product, the question becomes whether you should use a chip or a module solution. The option you choose depends both on your strategy for taking the product to market as well as the engineering strengths of your company. Let’s start by identifying a few advantages and disadvantages of each solution, and then we can see how these tie in with different marketing strategies.
The Advantages and Disadvantages of Both Chip and Module Solutions
A chip solution can easily be five to ten times lower cost than that of a module solution, so managers often look at this as the only possible option. Instead, it would be good of them to ask, “Why can these module companies charge so much more?” That’s because a lot of work goes into turning a chip solution into a fully featured product. Firstly, a chip solution will require FCC certification since the product transmits energy. If your strategy requires a very short time to market, then FCC certification in itself can push you over your deadline. If your design doesn’t meet the requirements and changes are needed, this will further add to the delay in bringing your product to market.
Secondly, a chip design will require selecting an appropriate antenna and designing a matched line to connect it to the chip. If your company does not have RF hardware expertise you may want to consider hiring outside help for this part of the design. Lastly, chip companies deal in volume, so you have to be wary of the minimum order quantity (MOQ) for parts. If your estimated annual usage is low at first, it may not make sense to purchase chips with an MOQ of 50k.
As mentioned before, the main concern with a module solution is usually the cost. The other problem can be size, but there are many modules out there with very small footprints, such as the BLE113 from Bluegiga. A module gives you the advantage of quick time to market, since it’s already FCC certified and the antenna is included onboard, so there’s no need for any RF design. Additionally many modules allow you to do quick prototyping to get an idea for the feel of the final product. If you require a very quick time to market and your company does not have deep engineering expertise a module solution may be the best way to go.
A Great Option: Start with a Module and Move to a Chip
At Symmetry, we often get customers who would like to use a module at first, but then switch to a chip solution when they start to sell in greater volumes. This is where it becomes important to pay attention to the firmware running on the module. The ability to use the same firmware on your chip solution as on your module can save lots of development costs once you’re ready to make the switch. For this reason we always recommend that customers use a module with the same chip onboard as they intend to use in their chip level design. An example of this is using an RFDigital module that uses a Nordic chip internally with the intent of moving to the Nordic chip later on. This makes the transition as smooth as possible.
If you’re weighing the pros and cons of BLE chip vs module design and would like our insight, we’d be happy to help. Please call Symmetry Electronics at (310) 536-6190, or contact us online.
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