When it comes to selecting a 10 Microfarad capacitor, it's essential to consider factors beyond price alone. Capacitor chemistries play a significant role in determining their behaviour. In this article, we compare two capacitor types: the MLCC capacitor by Taiyo Yuden and the polymeric tantalum capacitor by KYOCERA AVX. 

Gould DSO450: internals commonly known not only for battery leakage, but also for dead-short tantalum capacitors

Housing Differences:

One noticeable distinction between the two capacitors is their housing. The MLCC capacitor comes in a case size of 0805, while the AVX capacitor is in a smaller 0603 case size. This size difference can result in minor space savings when multiple capacitors are used on the bill of materials.    

Voltage Considerations:

Ideally, capacitor capacitance should remain constant regardless of the applied voltage, with breakdown occurring only when the maximum permitted voltage is exceeded. To analyse this behaviour, we employ the Bode 100, an impedance analyser specifically designed for capacitance and inductance measurements. By following the measurement process outlined in the YouTube video provided (https://www.youtube.com/watch?v=P-CjJVL1mrI), we can observe the resulting diagrams.  

The MLCC capacitor’s capacitance decreases as the applied voltage increases

The tantalum capacitor does not show this behaviour.

An interesting observation arises with MLCC capacitors, especially those with small cases. It is crucial to be mindful of their voltage limits. When the applied voltage approaches or exceeds half of the maximum, reliability issues may arise.  

Frequency Dependency:

The increasing prevalence of switch-mode power supplies presents new challenges for capacitors. Real capacitors possess various parasitic elements that become problematic as frequencies rise. To further compare the frequency dependency of these capacitors, we instruct the Bode 100 software to display all lines collectively, as shown in the figure.  

The frequency is increasing from the left to the right set hand side

Conclusion

The comparison between the Taiyo Yuden JMK212AB7106KGHT and the KYOCERA AVX F380J106MMAAH2 highlights the complexities involved in selecting passive components like capacitors in today's high-intensity electrical engineering environment. While the KYOCERA AVX capacitor offers more stable capacitance properties, it comes at a higher price and has a lower limit frequency. It is essential to weigh these factors carefully when making capacitor choices for specific applications.