AX5045 Component Determination


I am designing a transceiver circuit using AX5045. The datasheet, pages 31 and 32, shows how to determine the component values. I started to calculate component values using the AX5045 DEV board (ADD5045-915-1-GEVK). However, except for the 3 component values, the design is not matching with my calculations. I just want to get more information about this design. Unfortunately, the datasheet is not providing deep information about design-wise. I am looking for any helpful documentation or any supportive comments.



Please refer to the external component values of our ADD5045-915-1-GEVK: AX5045 915 MHz Add-on modules for DVK-2 Evaluation Kit and schematic + BOM for 915Mhz settings.

Thank you for using our community forum!

Hello. In addition to the reply above.
Please note that the ADD5045 uses the match for "Direct RX/TX Connection (Figure 9)" which is derived from the "Separate RX/TX Connections (Figure 8)". As reported on page 34:

A co−match for the PA and LNA is possible with some compromise to performance as shown in Figure 9. A large coupling capacitor Ccm is used to connect them together. The initial values of the PA and LNA input matching components are calculated using the previous equations.

So the equations in the AX5045 datasheet on pages 31/32 are provided for the "Separate RX/TX" case.