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Method for a stacked beam contact design for an LGA socket

IP.com Disclosure Number: IPCOM000146346D
Publication Date: 2007-Feb-12
Document File: 3 page(s) / 330K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method a stacked beam contact design for a land-grid array (LGA) socket. Benefits include improved performance and improved reliability.

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Method for a stacked beam contact design for an LGA socket

Disclosed is a method a stacked beam contact design for a land-grid array (LGA) socket. Benefits include improved performance and improved reliability.

Background

      LGA sockets require that each contact must maintain a relatively high contact force to operate reliably. To achieve the high force within a small space constraint (40x40x30 milli-inches) the contact spring must be very stiff and usually carry high bending stress.

Description

      The disclosed method is a stacked beam LGA surface-mountable contact design. The contact is stamped metal inserted into a plastic grid array (see Figure 1). A solder-ball pad extends from the bottom of the contact. The rolled spring is arranged in a pattern. The lower contact leaf is nested inside the top leaf.

      At installation, the LGA package mates and applies a downward force at point A (see Figure 2). The typical force would first deflect the segment of the beam A-B until it hits the lower beam at point C. Part of the load is then transmitted into beam CD, which causes it to deflect. The deflection on beam CD begins at corner D until the other end, point E, hits the base.

      The initial spring rate is low. As the beams are pushing on top of each other, the spring rate becomes higher and higher. This design fea...