STM32WL matching circuit included in the chip ?

[emil28]

Hello,

I am very interested in using the STM32WL for a wireless application. Is the matching circuit already included in the chip (so I just have to add an antenna) ? I don't find any information about this.

Thanks.

[lz1im]

Hello, SHATE.1. Well, that AN is Excellent aboutPCB design, it is more intuitive, with practical formulae. I think, rules and advices in that AN are enough for RF PCB design, at least below 1-1.5 GHz. The main problem, concerning this thread, is, that there is no information about impedance of receiver differential input at frequencies 150-960 MHz, which is operating range if STM32WL. Same situation is at transmitter output. Without that impedances, there is no possibility to apply that excellent AppNote,.

[Hamilton DC]

Hi @lz1im​ ,

Thanks for your appreciation of the AN5407. I'm finishing the next AN for the matching network of this series. It will be called AN5457 "RF Matching Network Design Guide for STM32WL Series". In this AN you will find the information that you're looking for. This AN will be available in few weeks.

Best regards,

Hamilton

[lz1im]

Hi HamiltonDC,

That is a good news. I will eagerly wait for AN5457. I am sure that AN will be as meaningful as the AN5407.

Best regards,

Pavel

[Hamilton DC]

Hello,

You can find more information in this document: AN5457 - RF matching network design guide for STM32WL Series

Kind regards,

Hamilton

[TWard.1]

Hello @Hamilton DC​ - sorry to jump on this thread but I'm looking for help with RF tuning of the PA.

The approach we are taking is to remove our STM32WL from the board and to measure the impedance with a VNA looking from the HP output, then search for a complex conguagate match to the values provided in Appendix A of your app note. We're able to find this match with some significant tuning (12.52+j3.67 at 915MHz) but this does not give us the power we expect. I wanted confirmation that my approach is valid beofre ripping up the design...