PCB Libraries Forum : IPC Class

Author: Tom H
Subject: 2176
Posted: 23 Jun 2017 at 1:19pm

Library Expert produces library parts for all 3 IPC Classes. The fabrication class code is mostly defined by through-hole pad stacks and not SMD pad stacks and Library Expert supports every standard SMD component family and they are good for all 3 IPC Classes. Other than the standard DIP, SIP and Header, most connector land patterns are created using the mfr. recommended pattern in Library Expert Pro.

IPC Class 1 - General Electronic Products – Includes limited life products suitable for applications where the requirement is function of the completed product.

IPC Class 2 - Dedicated Service Electronic Products – Includes products where continued performance and extended life is required, and for which uninterrupted service is desired but not critical.

IPC Class 3 - High Reliability Electronic Products – Includes products where continued high performance or performance-on-demand is critical, product downtime cannot be tolerated, and the product must function when required.

IPC-7351 3-Tier Density library system:

Density Level A: Maximum (Most) Land Protrusion – For low-density product applications, the ‘maximum’ land pattern condition has been developed to accommodate wave or flow solder of leadless chip devices and leaded gull-wing devices. The geometry furnished for these devices, as well as inward and ‘‘J’’-formed lead contact device families, may provide a wider process window for reflow solder processes as well.

Density Level B: Median (Nominal) Land Protrusion – Products with a moderate level of component density may consider adapting the ‘median’ land pattern geometry. The median land patterns furnished for all device families will provide a robust solder attachment condition for reflow solder processes and should provide a condition suitable for wave or reflow soldering of leadless chip and leaded gull-wing type devices.

Density Level C: Minimum (Least) Land Protrusion – High component density typical of portable and hand-held product applications may consider the ‘minimum’ land pattern geometry variation. Selection of the minimum land pattern geometry may not be suitable for all product use categories.

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