STSAFE-A110 is bricked during initial programming.

[TimJ]

Hello to the ST engineers or anyone familiar with problems when programming the STSAFE devices:

We are seeing about 10% of our STSAFE-A110 devices permanently fail during initial programming. Per the guidance in Section 5.2 of the data sheet (linked below), in our design we are connecting RESET to VCC, we have a 100nF ceramic cap from VCC to GND, and we also have a 4.7uF tantalum cap from VCC to GND. Any suggestions on what may be causing this permanent failure? How critical is S_VCC specified in Table 4? If the Vcc pin is above 0.3V at power-on (see 5.2.2), could this explain the behavior? Could using a 4.7uF cap instead of 10uF on VCC cause permanent failures? Thank you for any help you can offer.

https://www.st.com/resource/en/datasheet/stsafe-a110.pdf

 

[edvogel56]

I am experiencing a similar issue.  We also have RESET tied to Vcc and the 100nF Cap Vcc to GND and have tried a variety of different "add on" caps to see if we could address the ~10% brick rate.  I sent emails to several people from this chips group including schematics and oscilloscope captures of the power up and down during programming.  Also requested a reference design.  

I will post here if I find out anything.

Good luck!

 

[edvogel56]

Something to look at - Vcc Turn on time by my HW powering the STSAFE IC to 2.2VDC needs to be 44 uSec. It isn't, mine is closer to 100uSec. Review Table 4 on page 26 of DS13039 Rev 1 for more information.