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CC430F5137: Many of CC430 microcontrollers are partially damaged

Part Number: CC430F5137

Hello,

We have a full turn-key production line to our products in China. One of the main components in the product is CC-430 microcontroller. Our product is using in US and EU markets and CC-430 configured accordingly. For EU market we are using band 433MHz with Channel=5 (Tx frequency is 434MHz), for US market we are using band 915MHz with Channel=0 (Tx frequency is 915MHz).
In our last production batch, we got very low yield, about 70% in US products only. Almost all bad units are failed on RSSi (transmit) test. Our production partners sent us few failed units to analyze and figure out the problem.
We analyzed these units and found very strange behavior:
1) All units that were configured to band 915MHz with Channel=0 (Tx frequency is 915MHz), transmitted on different frequency, some units transmitted on ≈927MHz, some on ≈924MHz and some on ≈914MHz.
2) We re-programed these units to EU configuration, band 433MHz with Channel=5 (Tx frequency is 434MHz) and transmitted frequency was correct, 434MHz.
Its looks that some of the microcontrollers are partially damaged, that means low band is works ok and high band is damaged. I attached a picture of one of bad units with relevant marking data of CC-430.
Please note, this product exist more than 10 years and this is the first time that see a problem like this.
Please advise how we can check what happened with these components.

Thanks,

Alex Katsovich

  • - Has something happend on the production line between the batches? ESD damage, wrong BOM etc?

    - How does the spectrum look like for the samples that give wrong frequency on the 915 MHz band? Could you post how it looks like for the examples you listed above?

  • There is no known issues with BOM or ESD.

    I tested again bad units vs good one. Bad units transmit few frequencies, one of them looks ok.

    Attached a spectrum of 2 bad units and 1 good.

    Bad unit 1.rarBad unit 2.rarGood unit.rar

    Thanks

    Alex

  • I assume you uses max hold for these plots?

    The plots looks a bit different from what I expected. With a damage I would have expected that the energy was distributed over a large frequency area, here it could look like 3 CWs. If you look at the output power vs time, how does it look like?

    Does the chip change frequency after a time unit?

    How does it look like if you re-flash the "bad" parts with FW which just set up the chip to send a CW at a given frequency? Does it look differently depend3nt on the frequency you set the chip to send a CW on?

  • Hi TER,

    I use a max hold plot because our product in normal condition transmit a data once in 10 seconds.

    I tried to use FW that transmit a data in specific CW always (each second) without any condition, got same resultץ

    I'm afraid that we got a bad/damaged or fake batch of the microcontrollers, because same board with same chip and 433MHz band configuration works correct. 

    I don't know how to verify if a batch is damaged or fake. Does TI has any batch productions logs or reports?

    Thanks,

    Alex

     

  • I have to check if this is a valid batch next week.

  • The CC430 you have picture of comes from a TI batch.

    Based on the spectrum plots you have included in this thread I don't see what could be damaged in the CC430 since it looks like it produce a valid CW, it just change frequency in the observation period. 

    - Have you verified that the FW image you have for this batch is the same as for the previous batches

    - Are you able to test the failing boards with SmartRF Studio?   

  • I verified that is the same FW that we used in all production batches since Feb-2016.  Regarding the SmartRF Studio I am not able to test with.  

    I replaced the CC-430 in one of the bad units and the problem resolved. I have a bad chip and can ship it's to TI for investigation.

  • Did you do a full A-B-A swap? Meaning first the chip from PCB A (which fail production test) and use this on PCB B (which pass production test) and then take the chip from PCB and use this on PCB A? 

    CC430 is a chip that we have few returns on meaning that I don't know if we have kits in the office on which I can test  a failing unit on. On the boards that fails, do you have a debug connector of some kind?  

  • I didn't swap A-B-A format. I only replaced the CC430 in 12 bad units and in all units the problem resolved.

    Last question, can you check a date code according the providing a batch number in the picture?

  • Assembly of the device on the picture was done in June, 2020.