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TRF7970A: Half power output impedance matching

Part Number: TRF7970A

I am looking to test and compare the performance of the TRF7970A when operated in half and full power modes. According to the datasheet, the output impedance differs between half and full power (8Ω typ for half power and 4Ω typ for full power). The matching network provided as a reference in the datasheet (p75 and p77) is for full power operation. Is there a suggested matching network for half power operation?

Thanks!

  • Hello Customer, thank you for your question and interest in our products.

    The forum support of this product has been reduced to first reference our existing documentation and collateral. TI does not have plans to stop production or place the device into a “Not Recommended for New Design” status, we genuinely feel most questions on these devices can be answered by reviewing existing collateral and previous questions asked. Please feel free to continue to use this device as you see fit for your applications. For support, please take a look to the “Similar Topics” section at the lower right of the thread page. In addition, please consult the existing collateral in the “Technical Documentation” section of the TRF7970A product web page along with the Frequently Asked Question document. Alternatively, you can use the search engine of your choice to look for related E2E threads. With each of these resources we believe it will help with your question.

  • Thanks for getting back to me. I've already looked at technical documentation (datasheet, antenna design guide, FAQ, reference designs) and forum posts for the TRF7970A (most posts ask about antenna impedance matching) and haven't found any information to answer my question. The most relevant information I've been able to find is in section 7.3 of the datasheet, which only addresses the 4Ω output impedance case. From this post it seems to me that TI recommends customers just use the 4Ω to 50Ω network provided in the reference schematic for the full power case, even though some components differ from the Smith chart simulation shown in the datasheet. This makes me hesitant to design a matching network for 8Ω from scratch based on simulation, as I don't know the reasoning behind specific components in the 4Ω network being different so I won't know how/when to make similar adjustments to my own 8Ω network. I'm asking if TI has a network that has been designed and tested for 8Ω output impedance?