CC120XEM-868-930-RD: About arrangement of Saw Filter and LNA

Takashi Hosokawa

Expert 1455 points

Part Number: CC120XEM-868-930-RD

Hi All,

The customer is asking questions about Post's comments below.

The figure below is a circuit diagram of the antenna part of CC1125EM_Cat1_schematic.pdf in the article.

1. Is it correct to replace part A with SAW filter?

2. Is it correct to replace part B with LNA?

3. Should I delete the filter of part C?

Best Regards,

Takashi

over 4 years ago

0 TER over 4 years ago

TI__Guru**** 317180 points

Could you please give some context to the questions?

It is not clear why they want to move the SAW filter, if they want to use the chip with an external LNA, PA or similar etc.

0 Takashi Hosokawa over 4 years ago in reply to TER

Expert 1455 points

Hi TER-san,

Thank you for your quick response.
I will check with the customer so please wait.

Best Regards,
Takashi

0 Takashi Hosokawa over 4 years ago in reply to Takashi Hosokawa

Expert 1455 points

Hi TER-san,

Customer is verifying the waveform with a spectrum analyzer from the SMA connector on the CC1200EMK.

However, because there was no margin for near spurious, I was asked about inserting a SAW filter.

"CC1125EM-CAT1-868RD" is introduced for the use of the SAW Filter, but the customer thinks that it is better to have the SAW filter in the part A in the circuit diagram.

Will the spurious be improved by placing a SAW filter at point A and an LNA at point B?

Best Regards,

Takashi

0 TER over 4 years ago in reply to Takashi Hosokawa

TI__Guru**** 317180 points

"However, because there was no margin for near spurious, I was asked about inserting a SAW filter.": Which frequencies do they have spurious on?

If they want to remove spurious in TX they have to place the SAW filter in the 'A' position.

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CC120XEM-868-930-RD: About arrangement of Saw Filter and LNA