LAUNCHXL-CC1352P: 915MHz TX power good, 2.4GHz TX power bad

Allen Fernandez

I designed a circuit board that is a variant of the LAUNCHXL-CC1352P1 design, except I added a second SP3T switch in order to electronically control three antennas. See enclosed schematic & layout. Using SmartRF Studio, when I measure TX power @ 915Mhz on the LAUNCHXL-CC1352P1 board using the external SMA port (conducted RF measurement), the TX power level matches that of my board (on either ANT-2 or ANT-3). However, if I perform the same conducted RF measurement at 2.4GHz, my board is around 12dB worse. Any thoughts ?

TI-Radio-V0_RevB_working_sheet2_10202020.pdf

over 3 years ago

0 Allen Fernandez over 3 years ago

Intellectual 920 points

More info ... if I remove C491 and install C492=47pF, the conducted RF power @ 2.44GHz measured at P11 is the same as that on P11 of the LAUNCHXL-CC1352P1, so this tells me that the problem lies somewhere between the two back-to-back switches and the antenna port.

0 TER over 3 years ago in reply to Allen Fernandez

TI__Guru**** 317180 points

Have you tried to remove U600 and measure after C999?

I assume you have measured the control signals to the switch and verified that they are as expected.

I don't see any obvious potential issues on the schematic/ layout.

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LAUNCHXL-CC1352P: 915MHz TX power good, 2.4GHz TX power bad