Batch of Dead STMs received?

[MoralkaraLynn]

(Referencing forum post: STM32WL + ST-Link = Target no device found (Custom Board))

My team recently ordered a set of STM32WLE5CCU6 from Digikey for a LoRa Radio project of ours. We got the PCBs manufactured from a local vendor and began assembling our first set of boards.

Assembled four boards in total (please refer to the linked forum post for more details), none of the four boards responded to the ST-Link or the Bootloader UART.

To eliminate the possibility of our boards being faulty, we replaced a working STM32WL on a working board with one of the newly purchased ones, the board did not respond (same issue)

We remembered that we had ordered a few STMs a couple months back. So, we picked it up from our spare inventory and assembled board #5, all things worked as expected and we were able to test the functionality of our circuit.

We believe that such an issue is highly unlikely unless we have received STMs from a dead batch / production cycle.

Any insight into this would be greatly appreciated!

Thanks,

MoralkaraLynn

[Tesla DeLorean]

Push in harder at the distro, they have the primary FAE and support role

Open an Online Support Request 

https://www.st.com/content/st_com/en/support/support-home.html

[Andrew Neil]

---

@MoralkaraLynn wrote:

My team recently ordered a set of STM32WLE5CCU6 from Digikey

---

So have you contacted Digikey about this?

[Tesla DeLorean]

I'm supposing that occurred, product should be traceable, although the OP might have gotten partial tray/spools so might not have the original bar codes, labels, vacuum packages etc.

Can the PCBA do some X-Ray analysis, perhaps look for pop-corning if moisture levels weren't controlled/maintained? ESD?

Parts should have some production marking which should/could be shared with ST via the OLS system. Perhaps pictures, etc. to confirm context, orientation, general build qualitiy, etc

[MoralkaraLynn]

---

@Andrew Neil wrote:

---

So have you contacted Digikey about this?

---

My team is working on it, hopefully we have some data from them soon...

[MoralkaraLynn]

---

@Tesla DeLorean wrote:

I'm supposing that occurred, product should be traceable, although the OP might have gotten partial tray/spools so might not have the original bar codes, labels, vacuum packages etc.

---

Will raise a support ticket with STM after getting some details from Digikey

Can the PCBA do some X-Ray analysis, perhaps look for pop-corning if moisture levels weren't controlled/maintained? ESD?

---

Our PCBA is in-house and we are not equipped with X-Ray machines, so that is not doable

Could you please explain the "pop-corning" which I should look for?

ESD, well, we work on ESD mats, components are kept in ESD covers. So, that shouldn't be the case. Also, four in a row over a span of multiple days doesn't seem like an ESD issue to us.

---

Parts should have some production marking which should/could be shared with ST via the OLS system. Perhaps pictures, etc. to confirm context, orientation, general build qualitiy, etc

---

Where could one find these production markings?

I will click and attach some images of the STMs which have been soldered shortly

[Tesla DeLorean]

>>Could you please explain the "pop-corning" which I should look for?

Cracks, stress, deformation, delamination of the package.

I don't recall the MSL of these parts, but basically the issue would be mositure flashing to steam in the soldering phases, causing explosive damage to the part.

[MM..1]

Your schematics dont have UART1 on right pins for system bootloader. Read AN2606 

Your UART2 is on right pins then connect BOOT0 HIGH and some 3V3 UART bridge to PA2 PA3