lead pitch

**Lead pitch** is the **center-to-center spacing between adjacent package leads or terminals** - it determines PCB footprint density, assembly capability, and inspection complexity. **What Is Lead pitch?** - **Definition**: Pitch is measured between corresponding points of neighboring leads. - **Design Influence**: Smaller pitch enables higher I/O density but tightens manufacturing margins. - **Assembly Coupling**: Stencil design, paste volume, and placement accuracy depend on pitch. - **Inspection Sensitivity**: Fine pitch increases risk of solder bridging and hidden defects. **Why Lead pitch Matters** - **Miniaturization**: Pitch reduction supports compact board and product form factors. - **Yield Tradeoff**: Fine pitch raises sensitivity to coplanarity and alignment variation. - **Cost Impact**: Tighter pitch may require higher-precision assembly equipment. - **Reliability**: Insufficient pitch margin increases chance of electrical shorts. - **Qualification**: Pitch changes often require new footprint and process validation. **How It Is Used in Practice** - **Footprint Co-Design**: Align pad geometry and solder-mask strategy with target pitch. - **Capability Checks**: Validate placement and print capability before pitch reduction release. - **Defect Monitoring**: Track bridge and open defects by pitch class to guide process tuning. Lead pitch is **a key geometry parameter balancing density and manufacturability** - lead pitch decisions should be driven by total process capability, not only I/O density targets.