noise filtering caps in the power rails

Discussion in 'General Electronics Chat' started by gehan_s, Feb 5, 2013.

  1. gehan_s

    Thread Starter Member

    Sep 17, 2012
    hi all,

    I am routing this PCB in which I need to rout a couple of 6n137 digital opto isolators. Since they will be switching at about 1MHz I have added these 100nF ceramic disc caps in between each IC on the power rail. My question is, is it really necessary and what kind of caps, values are better for this purpose?

    It would also be helpful if you can give me some general tips on PCB routing.

    I have added a screen shot of the part I am talking about.

    Thanks in advance.
    Last edited: Feb 5, 2013
  2. #12


    Nov 30, 2010
    You seem to be doing it right. Every digital switching chip needs a power supply cap because of the nanohenrys in the copper traces. Keep up the good work and read on the upper area of the Chat page, "Decoupling or Bypass Capacitors, Why".