presently i am working on mixed signal design ,i want to know wich
component is recommended for shorting analog and digital grounds
1)inductor
2)zero ohm resistor
3) diode (schottky)
Shorting grounds? You mean where to connect the grounds?
This depends on your current paths. Normally I would expect grounds to
be connected at the power supply. Just connected, no diode, normally
no inductor too. The inductor is sometimes used to prevent emc into
the analog parts. But you have to be careful as it may even make
things worse. The analog and digital part are like 2 independend
systems, the are connected at the ground.
It ususally is important that digital currents do not flow through the
analog ground (and the other way around). That current would lead to
fluctuations of the ground, and when you do not have a balanced system
you use the ground as reference.
Take care at the point where you do the AD conversion. Use a convertor
with balanced inputs and connect the '-' input to the analog ground,
NOT the digital ground. When the convertor has only one input and uses
the GND itself as 0-reference, then this will be the point where the 2
grounds connect. Make sure nu digital currents flow through it.
It is not possible to give better info without seeing the schematics
or setup first. Or without knowing what you want to do: preventing
disturbances caused by digital currents into the analog part, or
preventing spikes etc coming from cables from the analog part into the
digital part.
Regards,
Pieter Hoeben
