nRF51822 BLE Flex Module

I have been working on the 128kB version of the nRF51822 chip, but it seems like the OTA versions of my firmware will not fit with the gcc toolchain. So, I will continue working with the 256kB version.

Yageo has a new chip antenna coming out that is 2.7dB peak and still a small traditional chip antenna. I have had issues with the Molex antenna getting ripped off the board in some situations. So, when possible I will try the new antenna.

I have finally been able to update this board. The BiPower OTG and Qi/USB Charger modules are mostly done. So I know what the pin outs will look like (which held this board back). So I should be sending a new design with the 3dB antenna and shield to OSHPark this weekend. The design just fits the Tag Connect pogo programmer and antenna just outside the shield. I also added optional components - a reset button, an RGB LED (in shield), and a 32k crystal.

As with all the other Flex Modules, I will be improving the castellation design shortly. In addition, I may try to add more GPIO pins. As the shield and the 3dB Molex antenna are similar heights, I can get away with closer trace routes with that antenna. So in addition to it being probably the highest gain chip antenna (especially for the price), it also improves the design. I'll also likely move to a 4 layer stack up, so I need to recalculate the co-planar waveguide. We should be able to start selling these when ready in the next month or two as a Flex Module is a "subassembly" not requiring certification. We will try to get it certified when it becomes popular.

Hi, we have been comparing footprints and placement.  At this point some of the smaller prefab almost fit, but not quite.  The big issue is the 2.54mm sized castellations.  They are too close for even the smallest shields.  Between that and antenna placement.  We may need to adjust the overall board layout.  Almost all common nRF51822 modules have shields, but they also have really poor antenna placement (according to manufacturer recommendations).  For now, we will not include component shielding.

We will be modifying 0.9B before testing to support a pre-fab shield over the circuit. 

Laird Technologies and LeaderTech both make reeled pre-fab shields that we will be evaluating.

Just added some additional "thermal" vias, 3 additional GPIO, and additional VCC and GND to the 2dB version.  Sending out to OSHPark to test.