As power modules become smaller and more powerful, the components inside must work harder. For output filtering capacitors, this means handling higher ripple currents than ever before. If a capacitor cannot handle this well, it heats up — and heat is the number one enemy of electrolytic capacitors.
When ripple current passes through a capacitor, its internal resistance (ESR) turns part of that energy into heat. The hotter the capacitor runs, the faster its electrolyte evaporates, and the shorter its life becomes. Choosing a capacitor with low ESR and high ripple current capability is therefore one of the most effective ways to improve power module reliability.
UF Capacitors’ TFS series is designed specifically for this purpose — miniature size, extra low impedance, long life, and excellent ripple current handling. This article explains why it matters and where to use it.
2. Why Ripple Current Shortens Capacitor Life
It helps to understand one simple rule that every power supply engineer knows: the 10°C rule. For aluminum electrolytic capacitors, every time the internal core temperature rises by 10°C, the expected lifetime is cut in half. Conversely, if you can keep the capacitor 10°C cooler, its life doubles.
Ripple current causes internal heating because of ESR. The more ripple current or the higher the ESR, the more heat is generated. Therefore, to extend life, you have two practical choices:
○ Lower the ESR — less heat generated for the same ripple current.
○ Use a capacitor rated for higher ripple current — it is designed to handle the heat without failing early.
The TFS series delivers on both fronts.
3. Key Strengths of the UF TFS Series
TFS series offers several clear advantages for engineers working on power conversion:
3.1 Extra Low Impedance (Low ESR)
TFS achieves “extra low impedance” through a high-conductivity electrolyte and optimized internal construction. Lower ESR directly means lower power loss and less self-heating at the same ripple current level — a straightforward benefit for any high-frequency switching application.
3.2 High Ripple Current Ratings
In the same case size, TFS capacitors typically support significantly higher ripple currents than standard SMD aluminum electrolytic capacitors.
These values give engineers real confidence when designing for higher power density.
3.3 Long Life at High Temperature
TFS series is rated for up to 5000 hours at 105°C (with some smaller case sizes rated at 2000 hours). This long-life specification provides a solid foundation for industrial and communication equipment that must operate reliably for years.
3.4 Wide Temperature Range and Low-Temperature Stability
Operating temperature range: -55°C to +105°C. Even at -40°C, the impedance increase is kept within a predictable limit (impedance ratio ≤3). This makes TFS suitable for outdoor, automotive, and cold-environment applications.
3.5 Frequency Coefficient for Easy Derating
Switching power supplies operate at frequencies from tens of kHz to several hundred kHz. The TFS datasheet provides a simple frequency coefficient table (e.g., 0.85 for 100–2200µF at 1kHz and above). Designers can easily adjust the ripple current rating to their actual switching frequency without complex calculations.
4. TFS vs. Standard SMD Aluminum Electrolytic Capacitors
|
Feature |
TFS Series |
Standard SMD Cap |
|
ESR / Impedance |
Extra low |
Moderate |
|
Rated ripple current (same case) |
Higher |
Lower |
|
Endurance at 105°C |
Up to 5000h |
Typically 1000–2000h |
|
Temperature range |
-55°C ~ +105°C |
Usually -40°C ~ +105°C |
|
Best suited for |
DC-DC, POL modules, industrial power, communications |
General consumer, non-critical filtering |
TFS is a direct cross-reference to Panasonic’s FT series, offering a reliable and cost-effective alternative.
5. Recommended Applications
The TFS series is well suited for:
DC-DC converters and POL (Point-of-Load) modules – where space is tight and ripple currents are high.
Industrial control boards and PLCs – requiring wide temperature range and long operational life.
Base station and communication power supplies – demanding high reliability under continuous operation.
LED driver output filtering – long life at elevated temperatures.
Automotive electronics – meeting AEC-Q200-equivalent grade requirements (where applicable).
6. Conclusion: A Simple Way to Improve Power Module Reliability
You do not need complex calculations to appreciate what the TFS series brings. By combining extra low ESR, high ripple current ratings, long life at 105°C, and a wide temperature range, UF Capacitors has created a practical, reliable SMD aluminum electrolytic capacitor for demanding power applications.
Whether you are designing a POL module, an industrial power supply, or a communication system, the TFS series helps keep your capacitor cooler and your product running longer.
Visit UF website for full datasheets: https://www.ufcapacitors.com/
Request samples for your current project: karin@ufcapacitors.com