Nrf51822 RF impedance

[Chester]

Hi guys

As a title , I want to know about impedance of RF P and RF N

[Asbjørn]

Please have a look in the nRF51822 product specification chapter 8.5.6. The optimum differential impedance is typically 15 + j85 Ohm.

[Trevor]

Well Asbjørn, I see a problem here. Looking at v3.1 of the spec, I notice two values, one for the QFN48 and the other for the WLCSP. Seems normal to have two values for two packages. BUT, in Figures 22-30, all referring only to QFN48, why are L2 and C5 different for the QFAC?! Either there should be different values for output impedance or L2 and C5 are wrong in the Figures. Which is it?

I guess a simpler way to ask the question is why are L2 and C5 different for the QFAC?