BLE difference between nrf51822 CDAB and QFAC

[unzeitig]

When I tried S110 examples like BLE proximity, beacon and hrs on QFAC, it works without any problem. Unfortunatelly I can not see any activity on pin VDD_PA of CDAB. Is there any difference between both chips from BLE point of view? How to simply debug it?

[Jørn]

Unfortunately, I am not aware of any way to read if the balun is sabotaging anything. The BAL-NRF02D3 should work fine. Do keep in mind VDD_PA will only go high during radio activity, and will remain low otherwise. So it will remain low for most of the time. You could try to check whether the high frequency crystal oscillator is functioning as intended, the radio will not function without it. If it doesn't, there might be a problem with the mounting of the crystal on your board.