STM32WB55 QFN48 Antenna Band Pass Filter

[EYalc.1]

Hello, I am from Turkey and I want to use my university project STM32WB55 SOC. However, I do not have the chance to obtain Murata production from band pass and low pass filters used in reference designs. MLPF-WB55-01E3 IPD will not be in stock until the project deadline.

[EYalc.1]

How can I find an alternative?

[Remi QUINTIN]

​Unfortunately, there is no second source.

The only way to replace it is to implement this matching network with discrete components.

[EYalc.1]

Hi Sir,

yes I thought of doing so too. But can you help me on how to implement the bandpass filter used for harmonics with discrete components?

[Remi QUINTIN]

You can achieve this with the components described inside the red square in the picture below.

[EYalc.1]

okay, so I understand this here, it would be okay if I don't use the low pass filter in the schematic.

[Remi QUINTIN]

This low pass filter issued to filter unwanted harmonics. Such filter is usually 50 ohms at both input and output. You may not need it. Up to you.

[EYalc.1]

I will use STM32WB55 with the zigbee protocol for the control and data reading of iot end devices. Do you think it would be a problem to transmit and receive without filtering harmonics?

[Remi QUINTIN]

​No. As long as you do not intend to go for certification, that's quite OK. You will get some harmonics but it should not disturb the communication.

[EYalc.1]

Oh, thank you sir. Now I can end the project with peace of mind.