Dotstar (APA102) LED strips decoupling capacitor on PCB
If you have ONLY the 2 planes, the inductances will be &lt;&lt; 1nanoHenry anywhere on the PCB, and one bypass cap would suffice. However, as soon as you start chopping up the planes (and I hope you only chop up the VDD plane, you'll need bypass caps by each strip because of the long thin VDD power distribution traces. Traces in air (no underlying plane) are about 1nanoHenry/millimeter (25nH/inch); traces over planes are about 5x lower, at 200 picoHenry (0.2nanoHenry)/millimeter. (thanks to peufeu for that number). You cannot use a leaded capacitor, if you chose to use only 1 bypass capacitor.