Q: Page 92. What is the definition of "routing class" of PCBs ?


The definition of the "Routing Class" of PCBs is described in the French standard NF C 93-713. The Routing Class characterizes the density of interconnection (and the tolerances for part placing). The following summary may be used:



Design values 1 2 3 4 5 6
Minimal Width of routed tracks (mm) 0,80 0,50 0,31 0,21 0,15 0,12
Minimal spacing between both tracks or pads (mm) 0,68 0,50 0,31 0,21 0,15 0,12



For a multi-layer PCB, the "Routing Class" is given by the layer with the highest density.

In a same layer, the routed area with the highest density defines the "Routing Class" of the layer.

For a complete definition of routing classes, refer to NF C 93-713.