- Mon Nov 07, 2016 5:02 pm
#57795
Life is full of tradeoffs. I like to use a linear regulator for it's lower noise but it is not as efficient as a switcher. So in my ESP8266 designs I tend to use a switching regulator to obtain 5 volts and then I use a 3.3 volt linear regulator.
Routing of traces and wiring makes a different. In noise susceptibility and also in radiated noise. I include different values of capacitors to handle the instantaneous current requirements. A larger value for lower frequency and smaller capacitors to handle the higher frequency demands. Larger capacitors will have a lower self resonant frequency and are useless for very high frequencies. I lean towards surface mount components as they have lower self inductance. For higher frequencies I tend to use multiple 0.1uF capacitors. Sometimes I will also add 10nF in parallel as well. Of course I try and put this as close as I can to the Vcc and gnd connections of the module. I try and not use through hole connections to the opposite side of the board but it doesn't always work out that way.
In series with all this I like to use an inductor to reduce the effect of transients coming through the power supply. I don't do this as often as I should.
Using a ground plane when I can but I tend to stay away from multilayer boards because of the additional cost. So I try and do what I can with two layers. Compromises are just a part of life, and circuit design.
Having done what I can for the power I also take equal care on the signal lines, in and out. Noise immunity is just as important there.
Of course manufacturability is important.
