If I'm designing a two-sided PCB, I understand that using a "copper pour" in empty PCB areas can help reduce/prevent noise. What is the best way to do this? Specifically:
- should I do a copper pour on both the top and bottom sides of the PCB, or just on one side?
- if I do a copper pour on both sides of the PCB, should they both be used as "ground planes" or should just one be used as the "ground plane" and the other used for V+? won't the latter create a lot of capacitance?
- should I do a copper pour on both the top and bottom sides of the PCB, or just on one side?
- if I do a copper pour on both sides of the PCB, should they both be used as "ground planes" or should just one be used as the "ground plane" and the other used for V+? won't the latter create a lot of capacitance?
there are a lot of compromises -- on the low noise preamp I just made (for replacing the circuitry in my HP465A) -- using the SSM2019 -- I defined the star ground system as NET 1, the ground planes as NET 0. All of the signal and power grounds are on NET 1 returning to the star. I then poured NET 0 on the top, placed a grid of vias at 200 mil intervals (where allowable) and poured copper for NET 0 on the bottom. The vias connect top to bottom and I over-ride the DRC to connect NET 0 and NET 1 at the star. Using a grid of vias is mentioned by Analog Devices (where I can't remember 🙂
I was actually forced into this by Ultiboard 7 since it was balky when pouring the ground planes in and of themselves.
Of course, this presupposes that you are transferring a schematic from your sim software to your pcb software. With Ultiboard you can redefine a net, I suppose it's the same in Eagle.
If you find working with groundplanes difficult, you can always use 3M adhesive backed copper foil -- this helped me out a lot with a noisy ADC environment. The 3M foil is solderable, quite easily.
I was actually forced into this by Ultiboard 7 since it was balky when pouring the ground planes in and of themselves.
Of course, this presupposes that you are transferring a schematic from your sim software to your pcb software. With Ultiboard you can redefine a net, I suppose it's the same in Eagle.
If you find working with groundplanes difficult, you can always use 3M adhesive backed copper foil -- this helped me out a lot with a noisy ADC environment. The 3M foil is solderable, quite easily.
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