TDK releases 125 V axial aluminum electrolytic capacitors for DC-link banks

TDK has added 125 V-rated components to its B43693/B43793 axial-lead and soldering star aluminum electrolytic capacitor series, and upgraded the 63 V range of its existing B41687/B41787 series. The parts are intended for DC-link capacitor banks in systems running from 48 V up to 120 V: small xEVs, micromobility platforms, forklifts, electric boats and humanoid robots.

The B43693/B43793 series spans 125 V to 250 V, handles ripple currents up to 21.6 A and operates at temperatures up to +140° C. Capacitance runs from 56 µF to 650 µF in can sizes from 16 x 25 mm to 21 x 49 mm (diameter x length), and both series are rated for a useful life of 2,500 h at ambient temperatures up to +125° C. TDK says the 125 V variant is generally used for 96 V system designs that are constrained on space, exposed to high thermal stress and subject to dynamic load conditions requiring stable energy buffering.

The upgraded B41687/B41787 series covers 25 V to 63 V and shares the same axial-lead and soldering star construction, which standardizes design across voltage classes. Those parts operate at up to +150° C and offer capacitance from 510 µF to 4,800 µF.

Supporting a higher DC-link voltage in a single component removes the need to connect capacitors in series, which TDK says can simplify capacitor-bank design and improve system robustness and efficiency. Series-connected electrolytics normally need voltage-balancing resistors across each capacitor to keep the string’s voltage evenly divided.

TDK characterizes all four series by low equivalent series resistance (ESR) and high ripple current capability, which it says reduces power losses and improves thermal efficiency in the DC-link stage of an inverter.

Vibration resistance is rated at up to 20 g as standard, and up to 60 g is available on request. The axial-lead and soldering star terminals allow horizontal or vertical mounting on PCBs and busbars.

Mounting the 125 V parts of the B43693/B43793 series to a heat sink more than doubles their rated ripple current, which TDK says lets designers use fewer capacitors per bank and cut assembly costs. The specified ripple current of an 18 x 30 mm component rises from 5.2 A at +105° C ambient to 11.1 A when the aluminum case is held at +105° C by a heat sink.

Source: TDK