Power Dissipation

Resistor Power P = I^2*R = V^2/R = I*V

Thick Film Chip Resistor Power Dissipation

Footprint Power Rating
0201 0.050W
0402 0.063W
0603 0.100W
0805 0.125W
1206 0.250W
1206 Wide 0.500W
1812 0.500W
1812 Wide 1.000W
2010 1.000W

PCB Layout Considerations

Dimenions described below are in mils (1 mil = 0.001 inch)

  1. Smallest via depends on finished material thickness. PCB Manufacturer would like to see the hole aspect ratio at less than 5:1
    a. Meaning on a .062 thick board with a .062 via would be a 1:1 ratio
    b. a .031 hole would be 2:1 ratio and so forth
    c. Ideally they do not like to drill smaller than .013 on a .062 with a pad size of at least .026

  2. Minimum trace width will vary depending starting base copper weight.
    a. On a 1.0 oz base copper they can do 8/8 .
    b. On a 0.5 oz base copper they can do 5/5 .
    c. that is trace/trace pad/trace pad/pad

  3. Try to minimize number of drills, although many board houses have no penalty for number of drill sizes.

  4. Mistakes are endless. The single biggest mistake really is just not calling out or identifying what you would really like i.e copper weights, color of mask, stackup on multi layers, panel requirements etc...