----- Original Message ----- From: "David VanHorn" To: Sent: Tuesday, December 18, 2001 4:58 AM Subject: Re: [EE]: Aluminum caps vs. Tantalum snip > It is also important that the PCB layout supports bypassing. > Layouts that have the cap from VCC on one chip to GND on another chip are > fatally broken. > > I generally use a few zero ohm resistors to steer grounds, a few 1-10 ohm > resistors, a few 0.1 and/or 0.01uF caps, and that's about it. > snip On this subject, why, on a four layer board (or 6 or 8 or 16), do the power planes usually go in the centre and the signal layers on the outside. Isn't it more logical to put plane on the outside to catch EMI/RFI? Why have power planes at all. If you used them as signal layers you would have almost an extra 2 layers. -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu