Motorola Corporation

Motorola Solutions, Inc.

Michael J Watkins

Thomas J Swirbel

Scott G Potter

Jeffrey A Underwood

Method and apparatus for spatially optimizing the arrangement of surface mount pads on a ball grid array package. An array containing T surface mount pads with a diameter less than or equal to 0.4 millimeter is arranged in an array of rows and columns less than or equal to 0.5 millimeters center-to-center. The array of pads is subdivided into N groups of pads respectively numbered G(for X from 1 to N), each group containing Ppads (for X from 1 to N). Each pad in each group is located so as to maximize the number of empty spaces Sthat are adjacent to each pad, where S=(G&#x2212;1). The number of fanout possibilities for each group (P*S) is calculated, and then the total number of fanout possibilities, FP, is calculated using the function &#x3a3;(P*S). The resulting spatially optimized pattern has a quality score, FP/T, that is equal to or greater than 2.

Method and apparatus for spatially optimizing surface mount pads on a ball grid array package

An electronic assembly has a double-sided leadless component (10) and one or more printed circuit boards (30, 32). The component has a plurality of electrical terminations or pads (18) on both opposing major surfaces. Each of the printed circuit boards has a printed circuit pattern that has a plurality of pads (34, 36) that correspond to the electrical terminations on both sides of the double-sided leadless component. The electrical terminals on one side of the component are attached to the pads on the first substrate and the electrical terminals on the other side of the leadless component are attached to the pads on the second substrate. The printed circuit boards are joined together to form a multilayered circuit board (44) so that the double-sided leadless component is buried or recessed inside. The component is attached to the pads of the printed circuit board using solder.

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Sunrise, FL, United States of America

Michael J Watkins