Here would be my first 2 suggestions in changes to your circuit: #1: I would definitely place the ground from my logic circuits straight to the main power ground, instead of routing it though the 5V buck module. The buck converter is also a switching power supply and this could very well be coupling noise through the rest of your circuit, especially if it is the only ground path for the logic.
#2: If #1 does not fully alleviate the problem, I would try placing an electrolytic cap of between 100-470uF on the 5 volt rail close to the logic circuits. This could help decouple the logic from any noise entering through the 5V rail. Finally, if the above two do not solve the problem, I would use a linear regulator after the 5V module to provide a clean 5 volts to your logic circuits. It looks like the 5V module has a trim pot on it, so I would increase the voltage to 6 or 7, and then use a 5 volt LDO (low dropout regulator) to provide the final 5 volts. This certainly will alleviate a large amount of noise on this line that you might not even be able to observe on your scope, unless you zoom in quite a bit on the vertical (voltage) scale (so that you're looking at hundreds or even tens of millivolts per division). -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+unsubscr...@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/43021f26-824e-4f27-98b2-9af6da3f5e9d%40googlegroups.com.
