nRF54L family RF pin (ANT) output/input impedance

[sebasr]

I am curious about the RF pin impedance, as this parameter is not listed in the relevant specification for nRF54 SoC family (i.e. datasheet v1.0).

I wonder whether it is 50 Ohm allowing for direct antenna or amplifier connection.

[Asbjørn]

Hello Sebastian,

the ANT output is not 50OHm and antenna or amplification need to be attached after the L4 and C11 where it says "RF" in the schematic.

This is the 50Ohm point.

As Paal states, if you skip this, you will have a bad time with both performance and failing regulatory requirements.

Best regards

Asbjørn

[sebasr]

Well, I assume that I can design the matching network together with antenna. So I need to know what the impedance of that pin is. Could you let me know that value, please.

[Asbjørn]

Hello Sebastian,

No, please apply the reference schematic as is and then add the antenna tuning network after L4 and C11 in the schematic I attached earlier.

It is not possible to integrate the antenna input impedance matching into these components. We don't share the pin impedance because we do not want to support customers trying to do this. 

Best regards

Asbjørn

[sebasr]

In some cases, the PCB itself (material, stack-up) can impact the performance of the matching network. So it is reasonable to recalculate the circuitry. But to do so, the pin impedance is required.

[Asbjørn]

Hello Sebastian,

yes, manufacturing and process can and will affect the performance and that is why we recommend to manually tune the circuit performance by changing component values on the specific board for absolute optimum performance. It will depend on the components selected as well and all effects can't be simulated. As part of our development we start with estimated values for our internal development board and then we manually tune the component values until we find the right compromise for harmonic attenuate, output power and receiver sensitivity. The outcome of this process are the values seen the in the data sheet for nRF54L15.

Best regards

Asbjørn