| ??? 03/13/07 19:28 Read: times |
#134904 - As sure as one can be... Responding to: ???'s previous message |
From a Murata's application note:
What you see, is the effect of only ONE signal not running over a solid ground plane. Take note, that a rather slowly 74HC04 is driving the line. Do you still think that omitting the solid ground plane is a good idea? Richard said:
I've seen student-built boards that had no ground plane or power plane and were not too neatly hand-wired, yet worked quite solidly, often for long periods at a time without any hitches. So what? Only because they were lucky does not mean, what they did was right. Richard, from time to time we had members here who reported on strange behaviour of their projects. When we asked how their boards look like, they stated, that they have a breadboard design... Some had even 74FTTL on their breadboards! Hallelujah.. It's a matter of fact, that omitting the solid ground plane causes lots of ringing and ground bounce and heavily erodes the noise margins. Also, even the smallest digital boards will not meet the CE standards (radiation), when omitting the solid ground plane. So, it's not at all a good idea when you come here and tell the people, that a solid ground plane can easily be omitted! Are you sure, that your problems are not the consequence of using wire wrapping? Kai |
