STM32L152VDT6 extreme current draw on power-up

[Bolan69]

I have a design in which I am using an STM32L152VDT6 processor. The first prototype boards arrived, and one of the first things I noticed was that there was a resistance of 120 ohms between VCC and GND. I knew something had to be wrong at that point. After a lot of board checks, I concluded that the connections and parts were fine. I attempted to power up, and the current limit was triggered on my external supply, whcih was set to 3.3V. After ohming out a part that had not been placed on a board, I noticed that the following were pins were shorted:9,48,68,86, and 28. Also, pins 29,49,and 69 were shorted. The reason why there is a resistance of 120 ohms between VCC and GND is that there is 120 ohms between pins 28 (VDD3) and 10 (VSS5). At that point, we placed teh part onj a breakout baord and simply connected VDD1-6, VREF (toVDD), VDDA(to VDD), and VLCD (to VDD) and VREF-(VSS), VSS1-6, and VSSA. We tied BOOT0 low and nrst low. We again tried to power the part, with the same result. The power draw was over-range. At this point, I am at a loss as to what I might be doing wrong. We bought these parts through a broker, so I do not know if the parts could be corrupt. But I want to make sure I am not doing something wrong before I go down that road. Any help or advice would be appreciated.

[Tesla DeLorean]

Are you sure you've got the part correctly orientated?

[Bolan69]

Hi,

thank you for your reply. We are orienting the chip with Pin 1 at the dimple on the top of the chip and are counting pins counter-clockwise. We are using this pinout:

[Tesla DeLorean]

Ok, but a systemic problem with STM32 parts is that they are packaged at multiple locations with a lot of different equipment. The ejector pin marks on many of the parts are frequently broader than the Pin 1 dimple. There's a thread with photos.

High currents, and an inability to connect with SWD/JTAG would be specific big red flags.

Can you connect to the part on the board via the debugger?

Can you measure the voltage level seen on the NRST pin?

[Tesla DeLorean]

https://community.st.com/s/question/0D50X00009Xka68SAB/stm32f401-64pin-pin1-marking-orientation

https://community.st.com/s/question/0D50X00009XkePfSAJ/stm32f745-first-pin-location

I can dig for more, but this should clear up what my concerns are here.

[Bolan69]

Hi, Tesla,

Thanks for your reply. I am including pictures of the chip on the board. A recent development may be of interest. I could not get more of the STM32L152VDT6 parts, but we did manage to secure a couple STM32L152V8T6 parts. I ohmed these parts out and found that the shorts we saw on the VDT parts were not there. Power and ground were separated by 1Mohm or more. We bought in a test board breakout fixture with a ZIF socket and wired the board up with power/gnd/jtag. We were able to power the Z8T6 parts (new ones from Arrow) part (4mA current draw) and were able to talk to the part via STLINK2. We then dropped the ZDT part in the fixture and saw the same extreme current draw we did before. Can you think of anything that might be different between the two parts? I have to think the core is the same, but I may be wrong about that. Unless there is an anomaly that I do not currently understand, it makes me think the ZDT parts are either counterfeit or they are all damaged in the same way. That said, I am including pictures of the ZDT part on our board.

Again, thank you for your help.

Mark

[Tesla DeLorean]

Pin out for the 100-pin L152 look to be consistent.

Likely counterfeit

@Peter BENSCH​ can you push this up the chain, thanks.

[Peter BENSCH]

Well, if the STM32L152VDT6 had been bought from a reliable source, one could pursue this further. If, however, because of the still extreme worldwide demand, the goods were bought from a broker who in turn got them from highly dubious sources, only the broker can be held liable.

If necessary, look for someone who x-rays the broker parts, as it can often be seen that another die or, as already seen, nothing at all, as can be found here or there, for example.

Good luck!

Regards

/Peter

[Bolan69]

Hi, Tesla, Peter,

Yes. We managed to secure a STM32V8T6 part and have confirmed that the parts from the broker are bogus. Thank you for the links as I was going to inquire about Xrays. I really appreciate your responses!

Thank you

Mark