Series-parallel capacitor configurations target LLC resonant circuits

TDK Corporation expanded its CN series of low-resistance soft-termination MLCCs. This product achieves 22 nF capacitance in the 3225 case size (3.2 x 2.5 x 2.5 mm) and C0G characteristics at 1000 V. Mass production of the product series began in September 2025. The capacitors of the CN series are products that are equivalent to regular products in terms of their terminal resistance due to the optimization of their resin electrode structure.

There has been an increase in the use of multiple resonance capacitors placed in series-parallel circuits for resonance applications such as LLC resonant circuits and wireless charging. As applications become more powerful, they require more resonance capacitance, which increases the demand for high-voltage, large-volume capacitors. To improve reliability in these applications, components with resin electrodes prevent placement cracks resulting from external stress. However, the increased resistance value of resin electrodes has been an issue.

TDK developed the CN series with optimized resin electrode structures, resulting in lower resistance values. In addition to the low losses and capacitance stability over temperature and voltage variations of C0G products, these resin electrode structures achieve both high reliability against external stress and reduced loss, making them suitable for use as resonator and snubber capacitors.

The optimization of product and process designs has made it possible to manufacture these products, which helps increase reliability and application to high-voltage circuits and enhances the reliability of the applications. TDK will continue to expand its product line to meet the needs of its customers.

The capacitors target resonance circuits and snubber circuits. The unique terminal structure realizes soft termination MLCC, whose low resistance equals that of standard terminal products. C0G characteristics provide low loss and capacitance stability during temperature or voltage changes. Higher reliability of applications, reduced component count, and miniaturization are achieved with resin electrodes, high voltages, and large volume.