CC1125: Custom board designed for 915MHz could be used for 920MHz in Japan?

If I'm not mistaken the requirement for T-108 is -30 dBm both for 2. and 3. harmonic. This is the same as for ETSI. The CC1120 + CC1190 ref design for 869.5 MHz have two notches to attenuate the 2. harmonic sufficient. Since you want to operate in some of the channels in the 920 band you probably have to move the notches some to attenuate the 2. harmonic of this new frequency. The rest of the passives don't need to be changed. 

For the SAW filter: Since the maximum output power is 24 dBm in this band it could be that the SAW filter is not required. Use a placeholder for a SAW filter but test first without to see if it's sufficient. 

Many thanks for your quick response, TER

I am afraid that my english is not too good for understand some words. What do you refer with the "two notches"? 

I have been reading your document "AN126 - Using the CC1200 Under ARIB STD T108" and viewing the schematic CC1200EM 920, I see that it is very similar to the schematic of CC112x+CC1190 , changing some values of capacitors and inductors, and, of course, the use of the front end CC1190.

So changing (moving) the notches and viewing how the SAW filter acts on the TX/RX, could I use the same design?

Thanks again for your help, TER

For 915MHz, the components remarked on red boxes are not mounted. Forgive me for taking advantage of your knowledge, TER, but do you think I could still keep it that way for the 920MHZ?

I must recognized you that I don't have the radiofrequency knowledge and the tools to recalculate the radio circuit. Really, I take your designs and follow all your recommendations in our all radio designs.

If you want to operate according to T-108 you have to be able to recalculate and do a number of tests to tune and verify the design. 

OK, I understand it.

Thank you, TER.