STM32f302RCT6 Y revision package marking problem

Posted on September 04, 2014 at 14:44

Dear Forumers!

I've just started to solder in the pcb components into my pcb. I have a MCU as in the title mentioned, and I've faced a problem about the chip placement. In the official drawing the package only contains one marking circle, but in the reality the plastic chip package has two orientation marks:

A smaller and deeper left from the ST logo and a bigger and less deeper one above the ST logo.

First I've assumed that the first marking marks the no. 1 pin, but after soldering it and applying the voltage on it, the chip started to eject smoke and now acts as a short cut on the pcb. I have a remnant chip remained and I'd like to know which marks signes the first pin of the controller?

I have no battery option so Vbat is floating, and VDDA comes the same time as the VDD. I think this cannot cause this fatal error.

Any idea?

Thanks in advance!