Functional Test Fixtures Owned by the Factory or the Buyer
Buyer-owned test fixtures require explicit PO line items, complete source files, and calibrated limit audits to prevent factory lock-in.
Target Pad Pitch
Geometric Spacing
Design dimensions specify the distance between the centers of two adjacent solder pads on a printed circuit board. The target pad pitch determines the type of component that can be mounted and the precision required from the pick-and-place machinery. As this distance decreases, the risk of solder bridging between the pads increases.
It governs the layout of the circuit board and applies to the design and stencil printing stages.
Tolerance Constraint
The manufacturing process must be highly controlled when working with a very fine spacing. For a target pad pitch of 0.5 millimeters or less, the factory must use high-resolution stencils and specialized solder paste with smaller particles. If the placement machine is even slightly out of alignment, the component leads will not sit correctly on the pads.
This can lead to open circuits or weak solder joints that fail during testing. The engineering team chooses the pitch based on the size of the microchip and the density of the surrounding traces. Wider spacing is preferred for high-power circuits to prevent electrical arcing between the pads.
Placement Capability
The chosen dimension directly affects the cost and difficulty of the assembly. A consistent target pad pitch allows the manufacturer to use standard tooling and inspection programs. This geometry defines the physical limits of the circuit board design.