CCS / CC430F5137: balun for 433MHz

Valery Beloglazov

Part Number: CC430F5137

Tool/software: Code Composer Studio

Dear gurus!

I can not understand why the balun for 433 MHz in the filter circuit L5, L6, L7, C28, C29 (CC430F5137 datasheet page 86 figure 27 and table 48) lost almost 5 dBm?
What am I doing wrong?

Thanks!

Valery

over 6 years ago

0 TER over 6 years ago

TI__Guru**** 317180 points

You write that you loose 5 dBm. Compared to what? What do you measure, how do you measure it and what do you expect to measure?

0 Valery Beloglazov over 6 years ago in reply to TER

Prodigy 175 points

I connect the CC430F5137 to the SmartRF and set the output power to 0dBm.
On the output of the balun (with filter) ~ -6dBm.
I measure before the filter ~ -1dBm.
P.S. power meter (NRP-Z23 by Rohde & Schwarz)

0 TER over 6 years ago in reply to Valery Beloglazov

TI__Guru**** 317180 points

- The datasheet I find on the web does not have the page references you are are referring to. In www.ti.com/.../cc430f5137.pdf I find this on page 111.
- You should have measured close to 0 dBm out from the filter. Do you measure on a SMA connector?
- I assume that when you measure the output from the balun that you have disconnected the filter.
- Is this your own custom board?

0 Valery Beloglazov over 6 years ago in reply to TER

Prodigy 175 points

I measure it like this

0 TER over 6 years ago in reply to Valery Beloglazov

TI__Guru**** 317180 points

Do you have a picture how you have connected when you measure 0 dBm and -6 dBm?

I can do a quick schematic (need pdf) and layout (need gerber files) to see if I see something there that could explain poor performance. Send the files in a friend request if you don't want the files open on the forum.

0 TER over 6 years ago in reply to TER

TI__Guru**** 317180 points

Any feedback on this?

0 Valery Beloglazov over 6 years ago in reply to TER

Prodigy 175 points

excuse me.
I'm on a business trip.
I will return to the question in a week.

0 TER over 6 years ago in reply to Valery Beloglazov

TI__Guru**** 317180 points

Any update?

0 Valery Beloglazov over 6 years ago in reply to TER

Prodigy 175 points

Thank you for your consultation!
Found a mistake in the topology of the board! The engineer redid it.
But now at the output of the balun the power is ~ -8 dBm with a pattable = 0xC0

That is how it should be?

0 TER over 6 years ago in reply to Valery Beloglazov

TI__Guru**** 317180 points

It sounds like you still have a hardware issue.

I can do a quick schematic (need pdf) and layout (need gerber files) to see if I see something there that could explain poor performance. Send the files in a friend request if you don't want the files open on the forum.

0 TER over 6 years ago in reply to TER

TI__Guru**** 317180 points

I'm closing this since I haven't heard back from you.

0 Valery Beloglazov over 6 years ago in reply to TER

Prodigy 175 points

Thanks for the help.
I was immediately transferred to another project.
As soon as I finish, I will return to this issue.

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CCS / CC430F5137: balun for 433MHz