??? 11/07/04 18:38 Read: times |
#80615 - RE: Reducing the loop seems no way to el Responding to: ???'s previous message |
Prahlad said:
2. The only thing one can do is reduce the area of this loop by putting the two connectors close to the star ground point. And thus minimising the area of AGND affected due to noisy ground currents from DGND. You have put the power connectors closer to the ground star point. But look, even with this improve, digital return currents can still flow across analog ground plane and erode analog ground: ![]() So, it's necessary to keep the distance between power connectors and ground star point as short as possible. By the way, there's a nice methode to even further reduce the last portion of digital ground return current flowing across the ground star point: Common mode filtering! All you have to do is to feed the cables to power connectors through individual soft ferrite chokes. Keep in mind, that for common mode filtering both lines (+5V line and its according ground return line!) must be feed through the same soft ferrite. Kai |