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The RF impedence of TX port when work at 400Mhz

Question asked by VivienWei on Dec 10, 2017
Latest reply on Dec 10, 2017 by VivienWei

hello everyone,


we want to design a system using AD9361, and worked at 400Mhz. when reading the datasheet "AD9361_Reference_Manual_UG-570" P69 'Based on present load-pull data, the preferred TX output differential load impedance is 50Ω' and in some userfile it's recommended to set the RF Line differential impedance of 50 ohms for the TX. 

BUT when reading the recommended Baluns for other bands in 'Configuration Options for AD9361/AD9364 boards'


HHM1591D1 is recommended as TX balun which work at the frequency of 370MHz. BUT the impedence is 100:50, it doesn't match with TX differential impedance according to the datasheet. 


so, i'm confused how to select correct balun for system which work at 400Mhz, and how to set the differential impedance of TX RF line.