IWR1843BOOST: Power Backoff calculations

Isura Nirmal

Part Number: IWR1843BOOST

Hi Team,

I would like to know how to correctly calculate the power back-off values as I couldn't find everything I am looking for in the documentation.

This is what is in the document https://www.ti.com/lit/an/spracp3c/spracp3c.pdf

According to the document, For 6dBm power backoff, the corresponding value should be 0x060606

Appreciate it if you could answer the following questions.

Q1: What does it mean by TXBO = 3,6,9,12 as supported values?

Q2: Can I back off a value such as 6.5 dBm? should it be an integer?

Thanks a lot

over 3 years ago

0 E. Shareef over 3 years ago

TI__Genius 15820 points

Hello

Thank you for reaching out to Texas Instruments. I believe a set of values can be used for TX Back-off. But it ha to be an integer value.

Hope this helps,

-Shareef

0 Isura Nirmal over 3 years ago in reply to E. Shareef

Prodigy 80 points

Hi Ehtesham, thanks a lot.! So =what does it mean by the supported values 3,6,9,12?

0 E. Shareef over 3 years ago in reply to Isura Nirmal

TI__Genius 15820 points

The register that controls TX Back-Off is PF_TX_OUTPUT_POWER_BACKOFF. This is a 4 byte register, where the first three bytes define the TX Back Off for each TX. Valid values: [0, 1, 2, 3, 4, 5, 6, 12, 18, 24, 30].

I believe the document you quoted gives an example saying only 3,6,9,12 are supported. However, I will still look into this.

-Shareef

0 Isura Nirmal over 3 years ago in reply to E. Shareef

Prodigy 80 points

Hi Ehtesham, Thanks for the reply. The document says it's an 8-bit value per tx. As long as the following hexadecimal value gives 5dBm backoff for each antenna, I'm ok, but I need to be sure.
0x 050505

0 E. Shareef over 3 years ago in reply to Isura Nirmal

TI__Genius 15820 points

Yes, you should be able to set the TX Back off in this manner.

-Shareef

0 Isura Nirmal over 3 years ago in reply to E. Shareef

Prodigy 80 points

Thank you very much!

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IWR1843BOOST: Power Backoff calculations