| ??? 01/18/06 02:20 Read: times |
#107674 - What has God to do with this?? Responding to: ???'s previous message |
Joseph said:
It is extremely rare that anyone actually needs to physically split a ground plane into digital and analog parts. Sorry, but you are wrong! If you have a 16bit ADC, one LSB is 76µV at 5V full range. How do you handle this with hundreds of millivolts of digital noise on the ground, what you get, if you don't split the ground into a digital and analog section?? Joseph said:
But if you really are that unlucky soul who has so offended God that He has punished you and you really do need to split your ground plane, then there is one peril that you must either understand or rely on dumb luck to avoid. Never, make that NEVER, let a trace cross the split. What has this to do with Suresh's soul, God and punishment?? Of course you can cross the gap, but use a low pass filter when traversing it. The key issue of a proper mixed signal layout is to prevent the digital ground return currents from flowing across analog ground. How do you realize this? Kai |
