nRF905 external amplifier advice?

[mcguire]

Hi folks! First post here. Can anyone recommend an external amplifier (preferably preamp and PA, but just a PA will do) for the nRF905 for use at 900MHz?

           Thanks,
           -Dave McGuire
            [email protected]

[FormerMember]

Unfortunately, Nordic doesn't have any specific PA that we can recommend. However, any PA designed for 915 MHz should work. Just remember to not exceed the maximum output power for passing FCC/ETSI if you plan to qualify for those standards.

[mcguire]

I understand, thank you. Most of the 900MHz amplifier chips I'm finding on the market have separate Tx PA inputs and Rx preamp outputs. Do you have any advice on T/R switching for them, to drive them from the nRF905?

        Thanks,
         -Dave

[mcguire]

Thinking about this some more...It looks like I ought to be able to just connect both together on an RF PA/preamp chip like the RFaxis RFX1010 or the TI CC1190, and do T/R switching by driving the PA-enable and preamp-enable pins on those chips from the PA_Vdd output of the nRF905, with one of them inverted. Do you concur?

       Thanks,
       -Dave

[FormerMember]

Yes, that sounds like the way to do it; control the RX/TX switching with VDD_PA, since that pin will go high when TX is active.