B
Bill
- Jan 1, 1970
- 0
Hi,
I need to design a 4-layer PCB for an analog circuitry that measures
EEG (10 uV to 1000 uV peak to peak, 0.5 Hz to 50 Hz).
My supplies are:
+5 V (for analog)
+3.3 V (for digital)
0 V (for analog and digital)
-5 V (for analog)
I know about (and have experience with) star topologies, to minimize
contamination from one section to others. That doesn't worry me.
I'm concerned about SHIELDING. I don't have much experience working
with uV signals, so I need to pay attention to what supplies/signals I
place on each layer.
I'm also not concerned about the +3.3 V supply, since it doesn't need
to power any IC close to the analog input.
I'm concerned mainly about +5 V, 0 V and -5 V. Where would you place
them, in the 4-layer PCB?
I was thinking of something like this:
Layer1 : 0 V plane + soldering pads for SMD parts.
Layer2 : +5 V and -5 V planes, sharing the total surface.
Layer3 : Signal tracks.
Layer4 : 0 V plane.
What do you think?
Thank you very much.
Bill
I need to design a 4-layer PCB for an analog circuitry that measures
EEG (10 uV to 1000 uV peak to peak, 0.5 Hz to 50 Hz).
My supplies are:
+5 V (for analog)
+3.3 V (for digital)
0 V (for analog and digital)
-5 V (for analog)
I know about (and have experience with) star topologies, to minimize
contamination from one section to others. That doesn't worry me.
I'm concerned about SHIELDING. I don't have much experience working
with uV signals, so I need to pay attention to what supplies/signals I
place on each layer.
I'm also not concerned about the +3.3 V supply, since it doesn't need
to power any IC close to the analog input.
I'm concerned mainly about +5 V, 0 V and -5 V. Where would you place
them, in the 4-layer PCB?
I was thinking of something like this:
Layer1 : 0 V plane + soldering pads for SMD parts.
Layer2 : +5 V and -5 V planes, sharing the total surface.
Layer3 : Signal tracks.
Layer4 : 0 V plane.
What do you think?
Thank you very much.
Bill