New Industry Products

TDK Releases a Series of High CV Aluminum Electrolytic Capacitors

November 11, 2020 by Gary Elinoff

The EPCOS B43647 series features snap-in terminals to facilitate easy PCB mounting

Members of the B43647 series of capacitors are all designed to operate at 450 volts. Capacitances from 120 to 1000 µF are available, with case sizes (diameter and length) ranging from 22 by 25 mm to 35 by 55 mm.


Snap-in terminals ease the task of mounting members of the B43647 series.
Snap-in terminals ease the task of mounting members of the B43647 series. Image courtesy of TDK 


What is an Aluminum Electrolytic Capacitor?

These components are composed of two aluminum foils separated by a paper soaked in electrolyte. The anode aluminum foil is coated with an oxide layer via a process called anodization. The other aluminum foil acts as the cathode.


Modified image used courtesy of Science Direct
Modified image used courtesy of Science Direct


The high capacitances of these devices are made possible in part by the close proximity between the anode and cathode. Additionally, the spiralization of the anode-electrolyte-cathode sheets allows the unit to fit a great deal of capacitor surface area into the relatively small physical volume of the capacitor.


Capacitance and Physical Size Availability

TDK offers a wide range of Snap-in Capacitors, the B43647 series along the B43548 series being the two newest families.

The diagram below, taken from a B43647 Data Sheet, outlines some of the choices TDK offers within this series.


Image courtesy of TDK
Image courtesy of TDK


As illustrated above, there are three separate size configurations available for a 450 volt, 270µF capacitor. In millimeters, with the first number being diameter and the second number being length: 

  • 22 by 45

  • 25 by 35

  • 30 by 25

The trade-off made between length and diameter make it more likely to find a size that can be accommodated within a given design. The company indicates, on the datasheet, that: “Other voltage and capacitance ratings are also available upon request.”



TDK quotes a ripple current capability of up to 7.22 A (100 Hz, 60 °C). 

The company quotes a useful life of 2,000 hours or better. Obviously, this presupposes a myriad of conditions, which are spelled out in detail in the datasheet.

Surge voltage toleration is specced at 1.1 times the VR of 450 volts.

Self-inductance (ESL) is ~ 20 nH

Equivalent series resistance (ESR), varying with temperature and frequency, are low.


ESR vs temperature and Frequency.
ESR vs temperature and Frequency. Image courtesy of TDK Data Sheet


Physical Details

  • Units come in an aluminum case, insulated with PET sleeves with no insulation sheet at the case bottom.
  • Snap-in solder pins for stouter mounting to the PCB.
  • Minus pole clearly marked
  • Minus pole is not insulated from the case
  • A safety vent at the base provides overload protection.

Terminal options include the standard version with two lengths, either 6.3 or 4.5 mm. A 4.5 mm, three-terminal version is available to ensure correct board insertion.



These robust, highly reliable capacitors stand up to fast charging and discharging cycles, suiting them for deployment in demanding servo drive applications. Other suitable applications include:

  • Frequency converters 
  • Medical devices 
  • Power Supplies
  • Photovoltaic Inverters
  • UPS Systems

Members of the B43647 series are not, however, generally targeted at automotive applications


Regulatory Approvals

The Capacitors pass the needle flame test according to IEC 60695-11-5 for all flame exposure times up to 120 sec.

The units are RoHS-compatible 

Complies with IEC 60384-4