Rubycon Corporation Snap-in Capacitors

Snap-in capacitors are primarily used in high-power applications requiring large capacitance values and high ripple current capability. Common applications include switching power supply input and output filtering, motor drive DC bus capacitors, solar inverter DC link capacitors, welding equipment, and industrial power systems. The snap-in terminals provide secure mechanical mounting to the PCB and can handle higher currents than radial lead capacitors. These capacitors are typically used in applications above 100W where high capacitance (1000uF and above) is required. The large case sizes provide better thermal performance and longer lifetime compared to smaller radial lead capacitors.

Use snap-in capacitors for high-power applications requiring capacitance above 1000uF and high ripple current.

USF and USG are both snap-in capacitor series with similar electrical characteristics but different lifetime ratings. USF series is rated for 5,000 to 8,000 hours at 105C depending on size, making it suitable for general-purpose industrial applications. USG series offers extended lifetime of 8,000 to 12,000 hours at 105C, providing higher reliability for critical applications. USG uses enhanced electrolyte formulation and improved sealing technology. Both series are available in similar capacitance and voltage ranges. USG typically has slightly larger case sizes for equivalent ratings due to the enhanced construction. For cost-sensitive applications with standard reliability requirements, USF is recommended. For applications requiring maximum uptime and extended service life, USG is the better choice.

Choose USF for standard industrial applications; select USG for extended lifetime requirements.

Snap-in capacitors mount to PCBs using snap-in terminals that lock into plated through-holes. The PCB must have holes sized appropriately for the terminal diameter - typically 1.0mm to 1.5mm depending on capacitor size. The snap-in feature provides mechanical retention before soldering. For assembly, the capacitor is pressed into the PCB until the terminals snap into place. Wave soldering is the recommended method for snap-in capacitors. Hand soldering is possible but requires care to ensure proper heat distribution. The large mass of snap-in capacitors requires longer preheating and soldering times compared to radial lead capacitors. Always follow Rubycon's recommended soldering profile to avoid thermal damage.

Ensure proper PCB hole sizing and use wave soldering for reliable snap-in capacitor assembly.

Snap-in capacitors can handle significantly higher ripple currents than radial lead capacitors due to their larger size and improved thermal performance. Ripple current ratings range from 2A to over 20A rms depending on capacitance, voltage rating, and case size. For example, a 10,000uF 400V capacitor in 35x50mm size might have 8-10A ripple current rating at 105C. The large aluminum can provides excellent heat dissipation. At lower ambient temperatures, ripple current capability increases - approximately 1.4x at 85C and 2x at 65C. For very high ripple current applications, consider using multiple capacitors in parallel or selecting larger case sizes with higher ratings.

Select larger case sizes or parallel configurations for very high ripple current applications.

Yes, snap-in capacitors are commonly used for DC bus applications in motor drives, inverters, and power supplies. The high capacitance values and voltage ratings make them ideal for DC link filtering and energy storage. For DC bus applications, select capacitors with adequate voltage margin (typically 20-30% derating) and ripple current capability for the expected AC ripple. Consider the RMS ripple current from the inverter switching and ensure the capacitor rating is sufficient. Multiple capacitors in parallel are often used to achieve required capacitance and distribute ripple current. Rubycon's USF and USG series are well-suited for DC bus applications with their high reliability and long lifetime ratings.

Select USF or USG series with adequate voltage and ripple current ratings for DC bus applications.