Bluetooth devices have to be tested, both from the radio certification side and the Bluetooth software stack certification side.  Even with a straightforward design it’s expensive – very expensive!  This is frustrating as in many cases by using a Bluetooth IC solution incorporating the Bluetooth stack and following the manufacturers app note for the PCB layout, the testing can become just a box ticking exercise, but it still has to be done.

Using A Bluetooth Module vs A Chip Based Design

Bluetooth OEM modules have usually gone through all the testing so you don’t have to.  You can slap one on your PCB and your ready to go, often with a faster development route too.  The catch is that it costs more in production than using the discrete components instead.  It can be even more frustrating that the Bluetooth IC the module uses is capable of running the embedded software your application needs, but you have to use a separate microcontroller because either the Bluetooth module implementation doesn’t allow it or if you do you would break the Bluetooth stack certification, requiring re-testing.

As a general rule of thumb, if your production volume is likely to be say 10k or 20k then going with a module is often an overall cheaper choice once your factor in the testing costs.  However if your production volume is likely to be say 100k then the testing costs will typically be overcome by the savings in production cost.