Kemet-Yageo Corp
Webinar Date: June 24, 2025
Key Takeaways
- Understanding ESR and Ripple Current Limitations: Gain a comprehensive overview of how these factors influence capacitor performance.
- Evaluating Capacitor Behavior: Discover how ripple current capability varies with frequency, temperature, and capacitor technology, along with insights on thermal resistance.
- Technology Comparison: Analyze the performance of different capacitor technologies, including Ceramic, Aluminum Electrolytic, Film, and Tantalum, in demanding real-world scenarios.
- Real-World Applications: Learn through practical examples like DC-Link and resonant circuits to apply your understanding immediately.
- Simulation Tools: See how advanced simulation tools like YAGEO’s Y-SIM can help you identify optimal capacitor solutions and streamline your design process.
Frequently Asked Questions
What is a good method for cooling down Capacitors?
- You can aways do external cooling of the PCB or consider to not place the Capacitor next to other “hot” components like Inductors or Diodes. Please also allow passive cooling. Heatsinks can be used or a technology that does not heat up so much.
How can I increase the limited lifetime of Aluminum Capacitors?
- Very simple: reduce the ambient temperature and the maximum voltage. For sure, you cannot reduce the application voltage, therefore chose a capacitor with a higher voltage range.
What are the future trends of Capacitors?
- Higher voltage – driven also by the demand from EV applications, but also higher temperature range and – if technically possible – downsizing. Within the Aluminum technology, the Hybrid or Solid Polymer Technology is increasing.
What are you doing for space reduction of capacitors?
- We are developing our own Film material, which is thinner, but also, we are optimizing the constructions and cases such as our rectangular aluminum capacitors.
What about creepage distance using ceramic caps in a 2000V application?
- For a 2000V application, ceramic capacitors must meet minimum creepage distances typically ≥5 mm for uncoated parts on a PCB
Please define what ripple current is.
- Ripple current is the AC component of current flowing through a capacitor, typically caused by switching or periodic charging/discharging. It generates heat due to the capacitor’s ESR (Equivalent Series Resistance) and is a key factor in determining the capacitor’s lifetime and performance.
Can I combine capacitor technologies in parallel to meet capacitance/ripple current demands?
- Yes, this will work to combine the technologies.
Can you exceed a capacitor’s rated ripple current for a limited time, as long as the case temperature does not exceed a specific value?
- No, you should not exceed the rated ripple current, even if the case temperature stays within limits. Ripple current rating is based on internal heating, not just external temperature.
I usually prefer to add caps in parallel, rather than 1 or 2 larger caps. Is it correct to assume the total ESR is also reduced and possibly frequency dependent?
- Using multiple capacitors in parallel lowers the total ESR because their resistances combine like parallel resistors. Different capacitor values also help improve the overall frequency response, since each has its own self-resonant frequency determined by its inductance. Parallel capacitors add redundancy as well—if one fails, the remaining capacitors can continue to function, reducing the impact of a single-component failure.
We came across a Tantalum capacitor burning on the board. What do you think can be the cause?
- MNO2Tantalum capacitors can burn or fail catastrophically if they are overstressed — the most common cause is Voltage Overstress. They have a derating guide on the datasheet. I would recommend looking into Polymer Tantalum capacitors.
Are there still Ecological and Conflict sourcing issues with Tantalum?
- No, we source our tantalum conflict free.
Are there acoustic properties that vary depending on the capacitor type?
- Yes, ceramic capacitors, especially Class II types (like X7R/X5R), are known for acoustic noise, while film and electrolytic capacitors are generally quiet
Can we replace X5R with X7R and which situation I can do that?
- Yes, you can usually replace X5R with X7R, as X7R has better temperature stability. But it’s not always a drop-in check your specific application and the datasheets.
Why calculate based on ambient temperature rather than maximum temperature?
- The ambient temperature is calculated because the component’s self-heating is added to the ambient temperature.
Is it true that Tantalum capacitors are sometimes prone to catching fire. Should they be avoided?
- That is only for the old technology MNo2 new polymer tantalum capacitors do not have that problem.
For interrupting high power direct currents, capacitors are used parallel with the switch contacts in order to divert excess voltage from the contacts at the instant the contacts separate. Are specific capacitors used for this application?
- Yes, specific capacitors are used they’re called snubber capacitors, typically film or ceramic capacitors (class 1) with high pulse handling and low inductance.
Do you have any tips for verifying temperature rise in the final application (thermocouples, etc.)?
- Verifying temperature in capacitors and the real operation of this condition is the key part of ensuring the reliability.
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