Surface-mount Coaxial Connectors
In today’s fast-paced environment of high density electronic equipment, surface-mount connectors are becoming an important part of the integration process. Most RF components are assembled onto surface-mount PCBs or into hybrid modules. The RF connector interface has been one of the more difficult areas to reduce in size without compromising the accuracy of the 50 ohm interface to the PCB. In addition, high frequency surface-mount coaxial connectors with a high quality snap-on interface are being demanded by wireless equipment manufacturers.
The SCX series surface-mount coaxial connectors satisfy these needs by providing an ultraminiature RF surface-mount connector for board-to-board applications and for use with RG-178 and other small-diameter cables. The new connectors feature a quick connect/disconnect interface with detent locking and a low profile surface-mount construction for tight PCB spacing. The mating cable connectors are available in a right-angle configuration to further facilitate tight packaging situations.
The SCX series connectors are easy to mount and maintain good board retention to withstand excessive mating and shear forces without the need for plated-through hole mounting. The connectors feature 0.025" standoffs to allow cleaning and solder inspection, and the beryllium copper spring lock assembly ensures a highly reliable and durable snap-on interface that permits 1000 mate/unmate cycles. The engagement/disengagement force required for quick disconnect is 1 lb (min). This snap-on interface facilitates blind-mate board-to-board applications. In addition, the air dielectric interface provides good RF performance. The SWR of a mated connector pair is £ 1.15 (typ) to 10 GHz. Figure 1 shows a return loss measurement to 20 GHz for an SCX series mated pair with an SMA adapter on each side. 
This SCX connector series is an improvement over the ultraminiature M series connectors, which have a 0.125" (max) diameter. The new connector series also features the 0.125" diameter but shortens the overall mating length of a connector pair dramatically. Thus, the smallest-diameter RF connector now offers the shortest overall mating length to provide the utmost savings in space utilization without compromising rugged mechanical performance and low SWR. This connector is suitable for low profile board-to-board stacking arrangements where overall mated component height is important. A 0.375" mating length significantly increases the mounting possibilities. Connector configurations include end launch and compliant pin versions, as well as a shortened right-angle version for tight right-angle bends.
Other features include a captive center conductor, integrated strain relief and crimp outer-braid terminations. The SCX series connectors are available in tape-and-reel packaging for automatic pick-and-place assembly. The connectors are designed for cellular, radio communications and avionics applications and are suitable for any application that requires a compact, low profile surface-mount RF interconnection. Additional information can be obtained from the company’s Web site at http://www.sabritec.com.
Sabritec, Irvine, CA (714) 250-1244