IV
CAPABILITIES AND LIMITATIONS
OP VIDEO GAME
INTERCONNECTION SYSTEMS
ROBERT L. SHAY, JR.
Manager, Industrial Sales Division
AMP Incorporated
Harrisburg, Pennsylvania
Introduction
This program is being tenured in an effort to offer some innovative ideas and methods of interconnecting printed circuitry, chips and hard wiring. The objective is not just to afford economics for lower installed costs factors but to proceed from here with extensions of the basic precepts and apply them to the resolvement of specific applications.
Prior to product presentation, consideration must be given to one important factor that is a major decision for any interconnection and that is plating.
Can we and/or should we use un-noble or noble plating and what are the limiting factors for the application involved?
Gold Vs. Tin on Connector Contacts
An electroplater made the observation recently that after all the high-powered design engineering that goes into an electric connector, followed by precision stamping and forming, and high speed assembly and application tooling, the ultimate success or failure of the product still depends on those last few microns of material which he puts on the surface of the parts. And someone else characterized an electric connector as two platings held together by supporting structures of base metals. While these descriptions are somewhat facetious, it is difficult to overestimate the important of the surface of electric connectors. The surface materials, its hardness, ductility, elasticity,–its electrical conductivity, oxidation rate, work function and catalytic activity,–its adhesion, cohesion, melting point, boiling point, vapor pressure,–and its porosity, density, galvanic potential and temperature coefficient–these are all important considerations for electric contacts in principle, theory, and actual practice. Without belaboring the point, it is simply observed that each of the properties mentioned above has been the subject of detailed investigation at one time or another, relative to specific problems in the application and performance of electric contacts.
The reason for the interest in surface properties is, of course, that these surfaces must form a contact interface that will provide for uninhibited flow of electric current across the junction. In modern electronic equipment this simple-sounding function cannot be regarded casually as a trivial matter. In more and more cases we are finding that the overall reliability of electronic systems is governed by the reliability of its interconnections rather than its active solid state components.
High reliability often bears a high price tag. With electric connectors, the price is significantly affected by the choice of whether or not to use gold on the contact surfaces, and how much must be used. The skyrocketing price of gold has caused many people to take a hard look at the necessity of using this very costly metal on connector hardware.
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