Tolerances and Design Requirements

1. Inner Layer Clearances
   We require a minimum of 0.010” inner layer clearance.
   
   
2. Copper to Edge of Printed Circuit Board
   Minimum of 0.010” (outer layers) and 0.014” for inner layers (0.020” preferred for inner layers). For scoring, minimum of .015 for outer layers and .020 for inner layers.
   
   
3. Pad Size/Annular Ring
   Pad size should be at least + 0.010” over finished hole size for vias and + 0.014” over finished hole size for component holes. This means the annular ring (radius of the pad) should be at least .005” for vias and a minimum of 0.007” for component holes.
   
   
4. Hole Size
   +/- 0.005”  Standard Spec
   +/- 0.005” Custom Spec default
   +/- 0.003” Custom Spec upon request 1 oz and 2 oz finished copper weight only
   Minimum finished hole size; 0.010”. Call your salesperson if you required a finished hole size less than 0.010”.
   
   
5. Printed Circuit Board Thickness
   Overall may vary +/- 10% (Minimum +/- 0.005”)
   Minimum finished thickness for 2-layer: 0.005” (Call if you need a thickness of less than 0.005”)
   Minimum finished thickness for 4-layers: 0.020”
   Minimum finished thickness for 6-layers: 0.031”
   Minimum finished thickness for 8-layers: 0.047”
   Minimum finished thickness for 10-layers: 0.062”
   
   
6. Inner Layer Thickness
   Tolerances do not apply to the inner layers of Standard Spec Orders.
   
   
7. Rout (Circuit Board Outline)
   +/- 0.010” (+/- 0.005” available for Custom Spec Orders upon request
   Note: We rout to your circuit board size using the center of the board outline on your mask layer.
   
   
8. Copper Trace Width/Spacing
   This is the minimum air gap between any two adjacent copper features. Trace width is the minimum width of a copper feature, usually traces.
   For trace width/spacing, we require a minimum of 0.005” for 1 oz. finished copper weight on outer layers. Premiums are added for trace/space specs less than 0.008”
   For 1 oz. finished copper weight (inner layers), minimum trace width/space is 0.005”
   For 2 oz. finished copper weight (inner & outer), minimum trace width/space is 0.007”
   For 3 oz. finished copper weight (inner & outer), minimum trace width/space is 0.010”
   For 4 oz. f inished copper weight (inner & outer), minimum trace width/space is 0.012
   
   
9. Conductor width, thickness and spacing
   When not specified by the customer, the minimum conductor width shall be 80% of  the pattern supplied by the procurement documentation.  Both internal and external conductor conductor  thickness  tolerance  vary with the weight of the copper foil used for fabrication and  must    meet or exceed values established by IPC-6012.  Conductor  spacing may be reduced by a maximum of 30% (IPC Class2) unless otherwise stated in the documentation.
   
   
10. Soldermask Swell
    This is the expansion of mask relief over pad area. Our minimum is 0.005” over pad dimension or 0.0025” each side. PCB Unlimited will modify files to meet the minimum dimension.
    
    
11. Slot Width
    Minimum 0.031” in width. For smaller width, call your salesperson for pricing and turntime.
    
    
12. Tab Rout Spacing
    Please allow 0.100” spacing between your individual pcbs for tab rout spacing. When scoring there should be no spacing between the circuit boards.
    
    
13. Silkscreen (Legend)
    0.005” minimum line width.

Deciding whether you need to order your printed circuit boards as a Standard Spec or as a Custom Spec boards is simply a matter of looking at the specs. Standard Spec circuit boards are built to the same standards as Custom Spec orders but with a more limited spec range. Standard Spec and Custom Spec orders are inspected to IPC Class II Standards.

Quantity doesn’t matter. We will make as few as one pcb as either a Standard Spec or Custom Spec order. No order is too small for us!

Quality is the same. All Standard Spec and Custom orders go through the same rigorous fabrication and quality check process.

Turnaround time is the same. We can produce your Custom Spec order just as quickly as our Standard Specs orders even creating them in one day if needed.

Standard Specs include:
 • All holes plated through (PTH) for all hole sizes in the drill program
 • Non-plated slots and cutouts (plated available on Custom Spec orders)
 • Green soldermask
 • FR4 (regular)
 • White legend (silkscreen)
 • 1 oz. Cu. Inner layers/Up to 2 oz. Cu. Wt. on outer layers
 • Overall thickness .031” .062”, .093”, or .125”
 • Trace/Space to 5/5 mils
 • Gold fingers
 • Lead-Free HAL Solder plating finish
 • Rout Tolerance +/- 0.010”
 • Hole Tolerance +/- 0.005”
 • Fiducials and/or Tooling Holes

Custom Specs include:
• Plated or Non-plated holes (if no specifications provided holes will be plated)
• Non-plated or plated slots/edges and cutout's
• Various laminates including high temp (tg) FR4
• Full range of finished printed circuit board thicknesses
• Different soldermask colors (default green)
• Different silkscreen (legend) colors (default white)
• Trace/Space down to 4/4 mils
• UL Markings (Also 94V-O upon request)
• Lead-Free logo markings on printed circuit boards (upon request)
• Controlled Dielectric and/or Controlled Impedance
• Inner layer Cu. Wt. ½ oz. – 3 oz.
• Countersinks/Counterbores
• Fiducials and/or Tooling Holes (no additional charge if requested)
• Hole Tolerance +/- 0.003” (if requested)
• Electrolytic Hard Gold plating finish (total board or gold fingers only) and other plating finishes to include  ENIG,  Soft  Bondable Gold, Nickel, Immersion Silver, and OSP. Also HAL available in both leaded and lead-free solder finishes.

NOTE:
1. We never charge Tooling NRE on Standard Spec orders. In addition, when you re-order your Standard Spec with no changes and go to Custom Spec we waive the tooling charge again.
2. You pay Electrical Test charges only once. If you pay as a Standard Spec you don’t pay again… even for a fixture when going to Custom Spec.