Forum Discussion
Altera_Forum
Honored Contributor
11 years agoNo solder paste was applied on Thermal Pad for AGND. What would this do?
We use the EP5382QI-T in our microprocessor board. In recent assembly lots of the printed circuit board we found that an aperture was missing in the solder paste stencil for the AGND Thermal Pad. ...
Altera_Forum
Honored Contributor
11 years agoAlex, how about at start/boot up of our processor. This device produces 1.8 VDC that is used by our Graphics processor and our Flash memory chips. We have a significant number of "no Communication" failures that we struggle to troubleshoot since we cannot communicate over our JTAG and have no access to the BGA pins for probing testing.
We have also seen our display "flicker" at hot which implies a problem with the graphics circuitry, but has been tough to track down root cause failure. We of course are fixing the stencil to apply paste for the next batch of boards, but we have hundreds to try and troubleshoot. Any more thoughts would be appreciated. Julian --- Quote Start --- To quote the datasheet: Note the use of the word 'must'. However, it doesn't discuss whether the device relies on this as an electrical connection to the PCB. It goes onto say 'This provides the path for heat dissipation from the converter'. I would suggest that, providing the device isn't getting hot, it'll continue to regulate well. As it heats up it's performance will suffer and there is a risk of the part failing. Hence, the need to remove any heat generated by the device from it. Worst case it may fail in a way that takes the rest of the circuit with it... You could bond a heatsink to the top of the package. This would help dissipate any heat generated by it. Regards, Alex --- Quote End ---