While many factors affect the design of printed circuit boards (PCB), the Institute for Interconnecting and Packaging Electronic Circuits has created specific guidelines that include such components as connectors. Connectors are defined as devices that have been designed to provide specified electrical or mechanical interface between the PCB and interconnection wiring or between printed circuit board assemblies. Functions of the connectors and methods of attaching the connectors to the board are major considerations in design.
Mounting Connectors
Since PC boards can be manufactured through automated processes in a single step, or mixed processes with multiple steps, rules are vital to allow necessary operations. In the single step process, clearance is required for attachment and inspection of leads to the connectors.
In mixed processes, connector placement must be done in such a manner that clearance is allowed for other steps. Automated placement of connectors must be considered in terms of stress to the board. Whenever possible, connectors should be isolated enough on the board that subsequent operations don't place unnecessary strain on soldered joints.
Connector Designs
The type of connector, mounting and means of providing contact with the leads is determined by the application. In cases where the connector is subject to extreme vibration, the board should be attached to the connector rather than relying upon contact friction. Fastening hardware must be specified in assembly drawings.
The specific hardware used must be detailed as well as the torque used during assembly. Where necessary, through-holes will be plated with such materials as gold to maximize conductivity. Where connectors are mounted in full contact with the board, clearance will be provided so that no plated hole is blocked by a connector.
Edge-board Connectors
Damage to the tang of edge-board connectors is minimized by the design of the mating parts. In some cases, the mating parts are designed where connections are made or broken before other connections, so as to put events in the correct order. Edge-board connector adapters can be used in place of male contacts to avoid problems associated with board warping or varying thickness on the board.
Efficiency
With the increasing use of computer-aided design techniques, simulations and design can be performed in a virtual environment. In this environment, design rules may be specified by the software. Design rules for connectors on printed circuit boards (PCB) can be based upon a number of factors such as operating efficiency.
Even when a parameter such as efficiency is chosen, a balance must be established between such things as overall efficiency and efficiency at a given time. Design rules for such software can be based upon the primary function of the software such as design or simulation.
Modeling and Simulation
Signal quality for connectors can be modeled by using Maxwall 3D software. After the connector model is created, the connectors can be embedded in a SpecctraQuest DML program to determine their operation in the board. The design rules specified by the software and the results of the simulation serve as further guidelines for design. The accuracy of the simulation is dependent upon the correct information provided during the simulation.
