Dsm2039

To follow up, I supplied 5V limited at 100mA to the power input of the PCB and used the thermal camera. What I noticed was the FPGA itself was the only major hotspot that appeared on the board. When I disconnected the power supply, I removed C408-C411 underneath the BGA and still found that there was a still short across VCC1V0 and the other rails (these capacitors the small ceramic capacitors that are used to decouple the FPGA core 1V0 voltage rail - so, worth a try to remove them as they were within the hotspot). At this point the FPGA seems to be the culprit for the shorted rails. I won't be looking to debug this any further. I am going to order a new board and ensure that there is more mechanical stability (standoffs) for the FMC mezzanine connector as I will still be connecting and disconnecting from this connector often so that I can modify the circuitry attached to the FMC connector for testing purposes.

Thank you both asmi and zygot for your replies. Okay - it would make sense that this isn't ESD then as I am usually quite careful with grounding myself. I agree that this could be due to mechanical stress on the FMC connector area of the board. It would flex a bit when a daughtercard for the FMC connector is continuously inserted and removed. There are additional through holes near that connector that I could place standoffs into that would stop the board from flexing. I will use a thermal camera to see if there are any hot spots appearing by the components nearest to the FMC connector.

I've been using my ZedBoard for about a month and yesterday after I got back from lunch I returned to my work, switched on the ZedBoard, and noticed that the Power LED no longer turned on. I am normally very safe by using an ESD strap with 1Mohm to earth ground, however, in this instance I am only 90% sure that I indeed grounded myself before switching SW8 ON. We've had another zedboard with the same symptom a month before I started work on this project. We needed to buy a new one, and now it is in this state again since I've started work on it. We are using to board to test and develop an Analog Front end for the Analog Devices AD4630, using the AD4630-EVAL card. Here's what I've investigated so far: The VCC3V3, VCC1V8, and VCC1V0 rails are shorted. VU12V0, VADJ, VCC5V0, DDR_1V5, MVDD, PLVDD, DVDD, AVDD are all okay. (I could tell that MVDD, PLVDD, DVDD and AVDD were okay by removing the FB to isolate them). Also, I know that this is not due to the supplies IC27 and IC28 as I removed the output inductor to isolate the supply from the respective VCC rail and the short remained even though the supply was removed out of circuit. I am running out of things to investigate at the moment. Based on this I am leaning towards this being ESD damage to the FPGA, often I am plugging and unplugging in the FMC connector in the lab as we are working with development boards on this connector. Although, as stated prior I have experience with other FPGA development boards and Microcontrollers and haven't had an issue with ESD in the past. I've had my Intel Cyclone FPGA for nearly 8 years in and out of my backpack and I've never had an issue with ESD while being a lot less careful than I've been with the ZedBoard. Any help or feedback that other users have experienced the same would be greatly appreciated! Dan