Standards of Printed Circuit Boards

Printed circuit boards (PCBs) are the backbone of modern electronic devices, providing a platform for mounting and interconnecting components. The following are some general standards for designing and manufacturing PCBs:

 

Standard board thickness: The most common PCB thickness is 1.6mm (0.063 inches). Other thicknesses are available as well, including 0.8mm (0.032 inches), 1mm (0.04 inches), and 2mm (0.08 inches).

 

Copper weight: The amount of copper on a PCB is measured in ounces per square foot (oz/ft²). The most common weights for inner layers are 1 oz/ft² and 2 oz/ft², while outer layers can range from 1 oz/ft² to 6 oz/ft².

 

Minimum trace width and spacing: These values determine the minimum size of the copper traces that can be used, as well as the minimum distance between them. The exact values depend on the manufacturing process, but typical minimums are 6 mils for trace width and 8 mils for spacing.

 

Drill sizes: The minimum and maximum drill sizes that can be used depend on the type of hole and the manufacturing process. For example, the minimum finished hole size for a two-layer board with a plated-through hole process is typically 0.25mm (0.01 inches).

 

Solder mask and silkscreen: Solder mask is a layer of polymer that covers the copper traces and pads to protect them from solder during assembly. Silkscreen is a layer of ink that is printed onto the board to label components and provide other information. These layers should be designed with sufficient clearance to prevent overlap or misalignment.

 

Board edge clearance: The edges of the board should have sufficient clearance to avoid shorts between copper features and the edge of the board. The minimum clearance depends on the manufacturing process, but typical values are around 0.1 inch.

 

Mounting holes: Holes can be added to PCBs to allow for mounting of the board in an enclosure or to attach components. These holes should be positioned and sized appropriately based on the intended application.

 

Overall, following these standards can help ensure that a PCB is manufacturable, reliable, and compatible with other components in the system.