Not sure it's about saving pennies, as I've had the same question=20 (quandry?) based on PCB space available. Not a definitive answer, but=20 I've learned that it all depends. In general the closer to the PIC's=20 power pins the better. At all power pins are better. I've found a=20 28-pin PIC driving a handful of 7-seg displays at ~20mA per pin works=20 nicely with a single 0.1uf cap approx 0.1" away from the pins. Another=20 app with a PIC only switching on/off a bi-color LED (changing maybe=20 minutes apart), works fine with a 0.1uf at the power-supply. Also=20 consider what analog circuitry you'll have and how the digital noise=20 will affect that. Some years ago there was a really nice tutorial on this, with=20 oscilloscope diagrams showing the noise at various points on the power=20 rails. It was enlightening to see just how much noise digital I/O's can=20 generate on the power rail. I'll see if I can find it. Cheers, -Neil. On 8/31/2012 9:31 PM, Dave wrote: > How lucky do you feel? This is not a simple question. Study the data sh= eet and app notes. Why so you seek to save nickels. > > Chetan Bhargava wrote: > >> As far as I understand, decoupling capacitors should be in closed >> proximity of power pins of a microcontroller. What is the usual and >> practical distance that they are put at? >> >> Although all the power pins need one cap, I have seen designs with >> single cap only around 3mm away from a PIC18F6520 non-power pin. Would >> that be stable given that PIC18F6520 has 4 sets of power pins? >> >> Thanks, >> >> Chetan Bhargava >> http://microz.blogspot.com >> --=20 >> http://www.piclist.com PIC/SX FAQ & list archive >> View/change your membership options at >> http://mailman.mit.edu/mailman/listinfo/piclist --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .