There is so much controversial material about splitting Analog and Digital ground planes on the internet and universities. It is nice to see that Texas Instruments is confirming my findings about the issues created by splitting/cutting the planes.
Don’t separate the analog ground and digital ground unless your are using an isolated ADC. The Altium designer consultant Zach Peterson has made many videos talking about it.
How about the power supply connection? If for some reason, only one power connector can be used to provide both analog and digital power (For example, a USB powered audio DAC), with a LDO or ferrite bead to isolate between them. Assume the connector is located at the digital side, then the analog return current will flow in the digital ground. Is there any solution to this? Maybe add a isolation transformer like SN6505 to eliminate the return path?
In theory is quite simple and straight forward tehnique. In reality, when there are ICs which dissipate power, and also communication lines, the tehnique gets complicated. Not to mention that shape and size of the PCB is cutomer dictated..
Separated ground planes make for a radiative antenna. Best to never break a ground plane. If you do, make sure your system doesn’t generate power feeding into the parasitic antenna and that the antenna can’t receive power that causes problems. The latter is beyond the capability of most engineers, so don’t do it.
There is so much controversial material about splitting Analog and Digital ground planes on the internet and universities.
It is nice to see that Texas Instruments is confirming my findings about the issues created by splitting/cutting the planes.
Don’t separate the analog ground and digital ground unless your are using an isolated ADC. The Altium designer consultant Zach Peterson has made many videos talking about it.
How about the power supply connection? If for some reason, only one power connector can be used to provide both analog and digital power (For example, a USB powered audio DAC), with a LDO or ferrite bead to isolate between them. Assume the connector is located at the digital side, then the analog return current will flow in the digital ground. Is there any solution to this? Maybe add a isolation transformer like SN6505 to eliminate the return path?
In theory is quite simple and straight forward tehnique.
In reality, when there are ICs which dissipate power, and also communication lines, the tehnique gets complicated. Not to mention that shape and size of the PCB is cutomer dictated..
Why are small caps placed closer
the smaller the mlcc cap, the betterthe high freq noise absorbtion.
Separated ground planes make for a radiative antenna. Best to never break a ground plane. If you do, make sure your system doesn’t generate power feeding into the parasitic antenna and that the antenna can’t receive power that causes problems. The latter is beyond the capability of most engineers, so don’t do it.
maybe clear your throat?