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April 25, 2026
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STM32WL55 output RFO_H output impedance

  • April 25, 2026
  • 1 reply
  • 70 views

Hello,

I am using a STM32WL55 UFQFPN48 in an application. I am only using the high power output (up to +22 dBm) and only plan on transmitting with this device.

I want to transmit in the 420-440 MHz range, but there does not seem to be any load-pull analysis data from within AN5457 which would give output impedance at this frequency. I can only find data for higher bands. 

Is this data found somewhere else? I would like to use it for simulation and calculation.

Best

Best answer by Saverio GRUTTA

Hello,

I can provide the optimum load for 490 MHz at 22 dBm.

Zopt = 14+ j10

P_level (dBm) = 22 dBm 

Pout = 21.9 dBm

IBAT = 108.5 mA

Best regards

Saverio

 

1 reply

Saverio GRUTTA
Saverio GRUTTABest answer
ST Employee
April 27, 2026

Hello,

I can provide the optimum load for 490 MHz at 22 dBm.

Zopt = 14+ j10

P_level (dBm) = 22 dBm 

Pout = 21.9 dBm

IBAT = 108.5 mA

Best regards

Saverio