Today, my colleague and me were checked some modules to find out if they are using counterfeit or genuine NRF24L01+ chips inside.
We removed the top of the IC and compared the internals with the photos found here:
In really cheap modules, we found counterfeit IC-s.
Those modules are similar like the following one (however, they work surprisingly well, but they are counterfeit):
Edit - I have tested these modules (so they are counterfeit):
We also checked the modules bought here:
It is an official store of Nicerf, the module can be found at their website here: http://nicerf.com/product_147_88.html
In RF24L01F20, we found authentic NRF24L01+ IC inside.
We also found original IC in these modules:
RF2401F20 module is better as it also has CE / IC / FCC certifications, so it is a much complete solution.
These photos are not really good and the process was way too destructive, but we were able to clearly identify that RF24L01F20 and L24L01-D03 modules are built with genuine Nordic NRF24L01+ IC.
Also, these modules produced the best performance of those I have tried. Good to know they both use original chips inside.
I hope this experiment also helps others as well.
Here is a photo of RF24L01F20 without metal cap:
Here is the same module with three genuine ICs on the left which have been purchased from Mouser:
This is a photo of the IC in L24L01-D03 module without metal cap:
Above ICs are all genuine.
Counterfeit ICs had also a bit different printout - for example, the top left square sign was circle on them and text alignment usually was not perfect, but it may not be a good way to identify if they are genuine or counterfeit.
I hope this may be a good starting point for others who also looking for original products.