The VIA connection in the SC-55 connects the resistor element to the solder pad through a via filled with silver paste. The solder pad then provides the electrical connection to the printed circuit board (PCB).

The electrical connection consists of three elements:

1. Conductive paste: located on the top layer, it is in direct contact with the resistor paste.

2. Silver paste: fills a pre-drilled hole in the component.

3. Solder pad: connects the silver-filled via to the printed circuit board (PCB).

The via must be precisely dimensioned and properly filled. Voids should be avoided. Proper execution is essential for the electrical function of the resistor element.

With the PCB via connection, the internal resistor terminals are routed through the filled via to the solderable pads. The solder pad then provides the electrical connection to the printed circuit board (PCB).

With over-the-edge, the conductive surfaces extend to the edge of the component. The connection uses external contacts that are routed around the edge. As a result, the connection design depends more strongly on the precision and quality of the component edge.

The defined connection geometry can have a positive impact on the solder joint, electrical contact, reliability, as well as manufacturing and inspection.

• Mechanical robustness and solder joint:
  The pads support controlled solder distribution underneath the component. This can promote more uniform solder fillets and reduce unwanted solder accumulation at sharp or irregular component edges. With over-the-edge connections, the ceramic breaking process can result in irregularities along the edges. A VIA-based pad geometry reduces the solder joint’s dependence on these edge geometries and can therefore help reduce the risk of solder voids or weak solder joints. Thermal cycling and vibration are relevant stresses, for example in traction drives, inverters, and industrial motors.
   
• Electrical Contact:
  The defined pad design of the PCB via connection can support lower and more predictable contact resistance and reduce parasitic variations between PCBs and manufacturing setups. Particularly in high-current applications, the VIA connection can also contribute to stable current-path integrity.
   
• Flexible placement and configurations:
  The PCB via connection can be positioned at the edge or at multiple locations within the component. Multiple vias enable additional connection configurations, for example with NTCs, diodes, or voltage dividers.
   
• Additional performance feature: high pulse energy load capability:
  An optimized layout design and high-quality thick-film printing ensure excellent pulse load capability. For further details, please refer to the SC-55 datasheet.

The connection is designed to provide more consistent electrical, mechanical, and thermal contact between the resistor and the printed circuit board. This can contribute to more consistent product performance.

Manufacturing and inspection: The connections are compatible with SMD processes and are particularly well suited for modern, automated series production. Clearly defined pads can facilitate optical inspection and solder-joint inspection. Fewer soldering irregularities can help reduce rework and yield losses during reflow soldering.

Have questions about the PCB via connection in the SC-55? Get in touch with us.