| Electronics > Projects, Designs, and Technical Stuff |
| ATmega2560 board overheating any idea's |
| << < (5/5) |
| maginnovision:
Might be the flash, I really couldn't get them to do anything. The project needed most of the IO in the 100 pin package and I went for larger flash models(1280 and 2560) because I needed to store a few 8kB images. Using external SRAM with XMEM interface was 20 IO then I needed another 50 or so IO for interfacing with everything else. 24MHz seemed pretty good. 0 Errors over 192 hour test period with sram, cpld interface, sd card, and display. Now I want to build an overclock test board and order a bunch of different chips to see what I could do. |
| RoGeorge:
It's the AMS1117 regulators. If the PCB is not properly designed, or they use the wrong type or values for the 1117's capacitors, it will self-oscilate and heat itself badly. |
| HendriXML:
To my understanding it (AMS1117) didn't get power on the input, so that means it can do crazy stuff when an output from another source is applied? One thing I asked myself is how they "merge" different sources in this design, when external power would be applied at the input and USB as well. In one of the sources there would actually be a little over voltage situation. (Reversing current) Or is this a design flaw, of which the heating up is a result? In that case removing the 5 regulator -if not needed- would be preferable. |
| maginnovision:
Most of my small 5V linear regulators have about 1.2K \$\Omega\$ output to ground. One I happen to have nearby burned about .5W with 5V on the output and nothing applied to input. |
| HendriXML:
--- Quote from: maginnovision on September 28, 2019, 05:49:36 pm ---Most of my small 5V linear regulators have about 1.2K \$\Omega\$ output to ground. One I happen to have nearby burned about .5W with 5V on the output and nothing applied to input. --- End quote --- So it's safe to say they are not designed to operate in that way. Depending on the power source it can draw a little or a lot (in my case). If external power is needed, then not using usb and thus programming via ICSP would be an option. |
| Navigation |
| Message Index |
| Previous page |