PLC010935BP: Doesn't work except at 5MHz.

Hunsup Jang

Part Number: PLC010935BP
Other Parts Discussed in Thread: THS6222

Tool/software:

Hi,

I bought three boards for this experiment.

I put the two boards into transmitting and receiving mode respectively and directly connected their output terminals with wires.The results of the experiment are that all of them do not communicate except for 5MHz. For other frequencies that do not work, the carrier frequency remains in the D=1 section. Therefore, all are displayed as 0 during decoding, and communication does not occur.

In my opinion, I think that the filter works as a feedback line at lower frequencies. Therefore, I think that this circuit should have a function to stop the driver IC when receiving so that it works properly.

Is this a design flaw or am I misunderstanding something?

(Oscilloscope waveforms can also be sent upon request.)

10 months ago

0 Alec Saebeler 10 months ago

TI__Mastermind 22754 points

Hello Hunsup,

Let me test this out on the lab bench. Thank you for bringing this to my attention. Once I confirm what I am seeing, I may have some debugging steps or questions for you.

Best,

Alec

0 Hunsup Jang 10 months ago in reply to Alec Saebeler

Prodigy 10 points

Hello Alec,

Thanks for your attention.
I solved this problem.
It seems that the THS6222 bias settings need to be changed when transmitting and receiving.
TX : Bias1, Bias2 -> L
RX : Bias1, Bias2 -> H

Best,

Hunsup

0 Alec Saebeler 10 months ago in reply to Hunsup Jang

TI__Mastermind 22754 points

Hello Hunsup,

Yes, you will need to control the BIAS-1 and BIAS-2 pins via the microcontroller or other settings.

Putting the THS6222 into shutdown mode places the output pins into high-impedance.

Best,

Alec

0 Hunsup Jang 10 months ago in reply to Alec Saebeler

Prodigy 10 points

Hello Alec,

I believe there is an error in Table 2-3 in document TIDUF48A. Would you please check it?

Best,

Hunsup

0 Alec Saebeler 10 months ago in reply to Hunsup Jang

TI__Mastermind 22754 points

Hello Hunsup,

I will take a look at table 2-3. Are you referring to the logic levels for each bias mode being incorrect with respect to the datasheet of THS6222?

Best,

Alec

0 Hunsup Jang 10 months ago in reply to Alec Saebeler

Prodigy 10 points

Hello Alec,

Yes, It does.

Best,

Hunsup

0 Alec Saebeler 10 months ago in reply to Hunsup Jang

TI__Mastermind 22754 points

Hello Hunsup,

The datasheet is accurate, the TIDA design guide has the error.

I will see what our process is for fixing this style of document.

If you want this to be tracked and have you receive email updates, you can use the 'Submit Document Feedback' button on the bottom left of the page with table 2-3. You can submit feedback asking for the table to be corrected, and use the tables you sent in your previous reply.

Best,

Alec

+1 Hunsup Jang 10 months ago in reply to Alec Saebeler

Prodigy 10 points

Hello Alec,

Sorry, I can't find the 'Submit Document Feedback' button. It looks like this on my screen.

I wish I could finish it, but I can't. Can you do it for me?

Thanks.

Best.

Hunsup

0 Alec Saebeler 10 months ago in reply to Hunsup Jang

TI__Mastermind 22754 points

Hello Hunsup,

The link will be blue text “Submit Document Feedback” in the bottom left corner of the design guide document (for the page with table 2-3).

To submit feedback you need to open the TIDUF48A document, find the page with table 2-3, and click on the blue link in the bottom left of the page.

This will help us track the change and provide a fix to you.

Best,

Alec

0 Hunsup Jang 10 months ago in reply to Alec Saebeler

Prodigy 10 points

Hello Alec,

Sorry, I misunderstood.

I did it through the documentation link as you said.

Thanks.

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PLC010935BP: Doesn't work except at 5MHz.