A manufacturer’s perspective on determining parts layout.

A land pattern refers to the footprint or layout of surface-mount components on a printed circuit board (PCB). It includes the arrangement of pads, or lands, to which component leads or terminals will be soldered. An accurate land pattern is crucial for ensuring reliable solder joints, proper alignment of components and optimal electrical performance of the circuit. Most electronic component manufacturers provide detailed specifications and guidelines for creating land patterns specific to each component, which should be followed closely during PCB design.

Conventional wisdom regarding via count is wrong. Here’s the proof.

Conventional wisdom has suggested:

The cross-sectional area of a via should have at least the same cross-sectional area as the conductor or be larger than the conductor coming into it. If the via has less cross-sectional area than the conductor, then multiple vias can be used to maintain the same cross-sectional area as the conductor. (IPC-2152, page 26, Note 1)

In other words, if the conducting cross-sectional area of the trace (width * thickness) is n times greater than the conducting cross-sectional area of the via, then we need n vias. Almost the entire industry believed this, including those of us at UltraCAD, until Johannes Adam and I began publishing our research results (Note 2).