The Amphenol RF 902-9040 is a surface-mount coaxial switch jack with a 4.30 mm plug diameter interface, designed for applications that need to reroute an RF signal path when the mating plug is inserted. The internal switch disconnects the normally-closed port when the plug engages, eliminating the need for an external relay or mechanical actuator in the signal chain.
Why the Internal Switch Matters for Your RF Path
The internal switch is the feature that sets this jack apart from a standard SMA or MCX receptacle. When unmated, the switch connects the center contact to an internal termination (typically 50 Ohm); mating the plug opens that path and connects the plug directly to the board trace. This is useful in test equipment, antenna diversity switching, or any circuit where the unused port must remain terminated to avoid an open stub reflection. The 0.2 dB insertion loss includes the switch contact resistance, which is low enough that it does not materially affect link budget at sub-6 GHz frequencies.
SMT Termination and Board Layout Considerations
Both the shield ring and the center contact terminate with solder to the PCB surface, allowing a single reflow pass in a standard SMT line. The gold body finish is solderable with no additional surface prep.
No official second-source cross-reference is on record; the internal switch feature is unique to this part number within the Amphenol RF coaxial switch family.