TDK’s new B25696H film capacitors bring 30 nH ESL and 200,000-hour lifetime to SiC power converter designs

TDK has released the B25696H series of MKP DC high-frequency film capacitors, a DC-link platform built around the low-parasitic requirements of SiC switching topologies. Capacitance spans 47 µF to 1280 µF across a voltage range of 900 V to 2000 V—covering the high-voltage DC bus architectures increasingly used in energy storage, industrial drives and HVDC power distribution.

The headline specs are a self-inductance as low as 30 nH and ESR down to 0.8 mΩ at 10 kHz, with ESR stability maintained through 100 kHz. Those figures come from an internal busbar configuration that distributes current evenly across the capacitor windings—parasitic inductance in a DC-link cap is largely determined by current path geometry, and the busbar design attacks that directly rather than relying on the dielectric stack alone. Ripple current capability reaches 91 A at +60 °C ambient and 10 kHz, which supports high-power-density converter stages without thermal runaway at the component level.

The B25696H uses metallized polypropylene (MKP) dielectric in an aluminum case with a resin top, available in 85 mm and 100 mm diameter cylinders. Terminals are M6 screw female with an M12 threaded mounting bolt. Operating temperature runs -40 °C to +85 °C at the hotspot. Rated lifetime is 100,000 hours at +75 °C hotspot and full rated voltage—extendable to 200,000 hours with voltage and temperature derating, which matters for ESS and grid-tied installations where cap replacement is an outage event.

For data center operators moving toward HVDC distribution and SiC-based bus converters, the 900 V–2000 V range and low-ESL design map directly onto the DC bus stages in high-voltage rack power architectures. SiC converters in that application switch at 50–200 kHz; at those frequencies a 30 nH ESL generates meaningful voltage transients if the DC-link cap can’t absorb them fast enough. TDK’s stated applications include energy storage systems, solid-state transformers, renewable energy inverters, traction drives and industrial motor drives.

TDK also provides a free CapThermal online tool for simulating thermal behavior and estimating component lifetime under application-specific conditions.