Surface mount RC devices

Abstract

Both discrete and array RC components are described using cofireable resistive material as part of internal electrodes of the device. The devices include a sintered body of multilayer ceramic material in which multiple first and second electrode layers are stacked. Each of the first layers comprises at least one resistive electrode pattern extending across the sintered body between respective pairs of terminations. The second layers comprise an electrode pattern extending transverse to the resistive electrode pattern, such as between end terminations. In some embodiments, opposing side electrodes serve as input and output terminals of a respective feedthrough filter. In a feedthrough arrangement, the third terminal may be provided by one or both of the end terminals. The invention also describes an improved termination structure including a layer made from a metal oxide material.

What is claimed is:  
     
         1 . An array device having a predetermined number of RC circuits in a singular package, said device comprising: 
 a device body defined by a plurality of first ceramic layers and a plurality of second ceramic layers arranged to form a stack;    each of said first ceramic layers having thereon a plurality of side-by-side first electrode plates, said first electrode plates being at least partially formed of a cofirable resistor material;    each of said second ceramic layers having a second electrode plate extending in a direction transverse to said first electrode plates, a predetermined number of said first ceramic layers being respectively adjacent to a corresponding said second ceramic layer such that said first electrode plates will oppose said second electrode plate to form two plates of a capacitor of a respective RC circuit; and    said device body having a plurality of terminations on side surfaces thereof, respective of said first electrode plates corresponding to one of said RC circuits being electrically connected to at least one of said terminations and said second electrode plates being electrically connected to at least another of said terminations.    
     
     
         2 . An array device as set forth in  claim 1 , further comprising: 
 a plurality of third ceramic layers arranged in said stack with said first ceramic layers and said second ceramic layers, said third ceramic layers having thereon a plurality of side-by-side third electrode plates at least partially formed of a cofirable resistor material;    a predetermined number of said third ceramic layers being respectively adjacent to a corresponding one of said second ceramic layers such that said third electrode plates will oppose said second electrode plates to form two plates of a capacitor of a respective RC circuit; and    respective of said third electrode plates corresponding to one of said RC circuits being connected to a corresponding one of said terminations.    
     
     
         3 . An array device as set forth in  claim 2 , wherein said first ceramic layers are alternately stacked with said second ceramic layers in a top portion of said device body and said third ceramic layers are alternated with said second ceramic layers in a bottom portion of said device body.  
     
     
         4 . An array device as set forth in  claim 3 , wherein each of said first electrode plates is electrically connected only to a respective one of said terminations.  
     
     
         5 . An array device as set forth in  claim 4 , comprising a total of four of said side-by-side first electrode plates on each of said first ceramic layers and a total of four of said side-by-side third electrode plates on each of said third ceramic layers.  
     
     
         6 . An array device as set forth in  claim 4 , wherein said cofirable resistor material comprises ruthenium oxide.  
     
     
         7 . An array device as set forth in  claim 2 , wherein each of said first electrode plates is electrically connected between first and second terminations, said first and second terminations being located on opposite sides of said device body.  
     
     
         8 . An array device as set forth in  claim 2 , wherein each of said second electrode plates extend between third and fourth terminations located at respective opposite ends of said device body.  
     
     
         9 . An array device as set forth in  claim 2 , wherein said second electrode plates are formed of a substantially nonresistive conductive material.  
     
     
         10 . An array device as set forth in  claim 9 , wherein said substantially nonresistive conductive material is selected from a group consisting of Ag, Ag/Pd, Cu, Ni, Pt, Au and Pd.  
     
     
         11 . An array device as set forth in  claim 2 , wherein said cofirable resistor material comprises ruthenium oxide.  
     
     
         12 . An array device as set forth in  claim 2 , further comprising at least one blank ceramic layer located in said stack such that said device will be provided with predetermined resistance and capacitance values.  
     
     
         13 . An array device as set forth in  claim 2 , wherein two of said second electrode plates occupy respective topmost and bottommost positions in said stack to enhance electrical shielding of an interior thereof.  
     
     
         14 . A composite RC device, said device comprising: 
 a device body defined by a plurality of first ceramic layers and a plurality of second ceramic layers arranged to form a stack;    each of said first ceramic layers having thereon at least one first electrode plate;    each of said second ceramic layers having a second electrode plate, a predetermined number of said first ceramic layers being respectively adjacent to a corresponding said second ceramic layer such that said first electrode plate will oppose said second electrode plate to form two plates of a capacitor;    said first electrode plates or said second electrode plates being at least partially formed of a cofirable resistor material; and    said device body having a pair of terminations electrically connected to said first electrode plate on each of said first ceramic layers, and further having at least one termination electrically connected to said second electrode plate on each of said second ceramic layers to provide a predetermined electrical function;    wherein two of said second electrode plates occupy respective topmost and bottommost positions in said stack to enhance electrical shielding of an interior thereof.