I have a very densely packed layout. It is 6 layers. And I had to run a couple of short traces on the ground plane.
The real question is most of my resistors and caps are 0402. And the reference designators are
1 mm Wide
1 mm Height
0.15 line thickness.
How small can I go and still be readable if made by a standard PCB manufacturing process. I do not want to pay more for special care.
I just discovered vias have options for Annular Rings.(I have not been paying attention)
The choices are
All Copper Layers (The default)
Start, end and connected layers
Connected layers only.
Because this is a power board I have ground planes, and a lot of Filled Zones with 2 oz copper on the top and bottom layers.
Why would you not want to have all vias be Connected Layers only?
It looks like plated through hole pads have the same options. Why would you not want all PTH pads Start, End and connected?
This example shows annular rings on five layers (All Copper Layers), but only two are connected. Do you want the annular rings on all five layers (as shown), or only on the layers connected (Connected layers only (1 & 4)) or on three layers (Start, end and connected (1 & 4 & 5)).
We recently received a board from PCBWay, W/H/T 0.18/0.18/0.14 mm. Dozens of reference designators, all legible. If I remember correctly, JLPCB is similar, and I have tried even 0.17 (several years ago) which resulted in some less readable characters, but still acceptable. My experience is that they don’t care about those values when they make the board – text can either be read or not, and they seem to assume it’s not critical and just make the silkscreen as you have defined it.
JMK, I know what it means. I am asking for practical purposes is there an advantage to having annualar on every layer versus only layers that have connections? Is the plating on the inside of the hole affected by having an inner annular ring on every layer versus not having an annular ring on every layer.
It makes the ground plane have more copper for the vias that are not connected. And I like that.
If there is no advantage why not make the default connected layers only for vias?
It depends on how much real estate is available on an unconnected layer. The annular ring and its associated clearance take up unnecessary space on an unconnected layer.
It also depends on the effectiveness of heat distribution when vias are used for that purpose.
Sometimes you want annular rings on unconnected layers, sometimes you don’t.
