PC-board designers can get a helping hand from the IPC-7351 Land Pattern Calculator being offered at no charge by PCB Libraries Inc. The LP Calculator is a scaled-down version of the LP Wizard. It calculates CAD library parts that comply with the latest revision of IPC-7351. The calculator generates results that perfectly match the LP Viewer library documentation. The tool relies on the data underlying IPC-7351, which includes fabrication, assembly, and component tolerance-based mathematical algorithms.
The calculator freeware supports a dozen component families, including: ball grid array, ceramic flat pack, ceramic quad flat pack, leadless chip carrier, metal electrode face, molded body, plastic leaded chip carrier, quad flat pack, small-outline IC, small-outline J-lead, small-outline transistor, and transistor outline.
IPC-7351, Generic Requirements for Surface-Mount Design and Land Pattern Standard, relies on dynamic calculations that represent a change in the way land patterns are defined, developed, and categorized. It is published by IPC, a worldwide trade association and standards-development organization. To get a free copy of the calculator, go to www.PCBLibraries.com.