Flexible ribbon probe for peripheral leads of an electronic part's package

Abstract

In-situ probing of closely spaced signals of SMT components uses a ribbon of flexible printed circuit material. Upon a first distal end of the ribbon are permanently soldered pins to be soldered to component leads carrying the desired signals. The ribbon may be bent to lie against a surface parallel to the plane of the PCB, where a small amount of adhesive or tape may secure it. That parallel surface may be an empty region of the PCB, may be the top of a component having peripheral leads that are being probed or the top of a nearby component, or (for signals emerging from beneath a BGA without peripheral leads) the parallel surface may be the top of the BGA part itself while the probe tips are soldered to the pins of a nearby SMT device, such as an R-Pack. A stiffener may be permanently carried by the ribbon proximate a location where it contacts the parallel surface. A second distal end couples the signal traces to small coaxial cables leading to the test equipment in use. Working components within the ribbon probe may be disposed thereon proximate the location protected by the stiffener. The ribbon material may be permanently bent to conform to the parallel surface, or it may be externally bent by an attached curved stiffener or by a curved rigid sleeve through which the ribbon passes. As an alternative, the probe tips themselves may be bent in lieu of a bend in the ribbon material.