14 Replies Latest reply on Oct 23, 2015 6:57 AM by userc_40862

    Burning up PSOC5s - Troubleshooting Question

    userc_40862

      Hello,

         

       

         

      Questions: 

         

      - What could cause the PSOC5 to heat up and cause the 3.3v bus to modulate a square wave?

         

      - Should I power the PSOC5 from whatever voltage Vdda has running to it?

         

       

         

      Background:

         

      I'm working on a custom board that uses a PSOC5 68 pin package. The design has the PSOC5 running of 3.3V, Vdda at 5v and most of the other Vddio pins are set to 3,3v. If I power the PSOC5 from the miniprog, it shows up in psoc creator and there is no smoke. If I then plug my benchtop power supply in and then reconnect the miniprog, the psoc doesn't shows up. If I then disconnect the benchtop supply and hook up the miniprog like in the first case, the psoc never shows up. When I solder up just the power supply part of my circuit, the signal looks good with no ripple. The rise time is about 0.055V/us. 

         

      To continue with the oddness, if I power a complete board (power circuit + psoc5) from the bench, there is a square wave on my 3.3v lines and the psoc5 gets to hot to touch. 

         

      I'm running out of boards to solder up so I thought I'd get a few opinion on this before burning more chips up.