first time designing RF, so pardon my ignorance. I want to design a ASK/OOK transmitter board operating on both 315Mhz and 433MHz ISM band frequencies. I have a MCU onboard that generates the data to be sent. I am hoping to use "data-in RF-out" transmitter IC like MICRF112 along with passive components and crystal.

Is there a way to use a single transmitter IC and have the RF-out switched between the 315MHz and 433Mhz RF arms. I think it may not be possible as the crystal that goes along with each frequency is different.

What would be the recommendation to minimize the BOM here - as most of the non-RF components are identical between the two transmitters? Thanks!


The MICRF112 uses relatively low frequency crystals (9.84 and 13.56MHz), so it should be possible to switch between two crystals using an analog multiplexer or even a mechanical switch. However you also need something to switch the RF output between two separate antenna circuits, so you won't be saving much (if anything) in BOM.

Considering the low cost and small size of the MICRF112, it might be better to just use two of them - each hard-wired to its own crystal and antenna matching circuit. You could tie the data inputs together and disable the unused IC via its EN input.


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