Components for nRF51x22-QFAA, QFAB and QFAC schematic

[joseph]

I have noticed that the reference schematic (the original if you can call it that, not the 1v8 or DC/DC) for nRF51x22-QFAA, QFAB and QFAC have different value capacitors and inductors. Why is that so?

I thought that the only difference between QFAA, QFAB and QFAC were the RAM and FLASH amount.

Are there any other traits between the chips that I am missing?

Thanks, Joseph

[Jørn]

Hello Joseph

Please see the answer in this question devzone.nordicsemi.com/.../

To summarize, QFAA and QFAB packages are of the same size while QFAC is a little bigger. Due to the difference in size of the package the impedance seen from the radio output towards the antenna is a little different. Therefore the matching network must be changed to compensate for this.

Best regards

Jørn Frøysa