Engineering Ultra-Low ESR in Surface Mount Capacitors

The relentless pursuit of higher power density and efficiency in modern electronic systems has driven the need for capacitors with increasingly lower equivalent series resistance (ESR). Achieving sub-10mΩ performance in surface mount capacitors presents significant engineering challenges that require innovative materials science, advanced manufacturing techniques, and careful application considerations. Nippon Chemi-Con's conductive polymer aluminum solid capacitor technology, exemplified in their PXF, PXJ, and PXS series, represents a breakthrough in ultra-low ESR performance.

Technical Fundamentals of Ultra-Low ESR Design
Conductive Polymer Electrolyte Technology

The foundation of sub-10mΩ performance lies in Nippon Chemi-Con's NPCAP™ (Nippon Chemi-Con Conductive Polymer Aluminum Solid Capacitor) technology. Unlike traditional aluminum electrolytic capacitors that utilize liquid electrolyte, these capacitors employ highly conductive polymer materials as the electrolyte medium.

The PXF series demonstrates remarkable ESR performance with values as low as 9mΩ at 20°C (100kHz-300kHz measurement frequency). Specifically, the 330µF/6.3V variant in F80 case size achieves 9mΩ while delivering 4,200mA rated ripple current at 105°C. This performance represents a significant advancement over conventional aluminum electrolytic technologies.

ESR Performance Comparison: Sub-10mΩ Achievements

PXF Series
PXJ Series
Sub-10mΩ Threshold

Figure 1: ESR Performance Comparison Chart- showing ESR values across different series and capacitance values. The illustration shows sub-10mΩ achievements across PXF and PXJ series with specific capacitance/voltage combinations.

Frequency-Dependent Impedance Characteristics

Ultra-low ESR capacitors exhibit complex frequency-dependent behavior that must be understood for optimal application design. The impedance characteristics follow the relationship:

Z(f) = √(ESR² + (XL - XC)²)

Where XL represents inductive reactance and XC represents capacitive reactance. At the self-resonant frequency, XL = XC, and impedance equals ESR.

The PXJ series, positioned as an "upgrade" from traditional designs, achieves ESR values ranging from 7mΩ to 28mΩ across its capacitance range. The 820µF/2.5V variant in F80 case size demonstrates exceptional 7mΩ performance, enabling high-frequency switching applications previously impossible with conventional technologies.

Impedance vs Frequency Characteristics

Key Insight: Ultra-low ESR capacitors maintain consistent impedance at high frequencies—critical for switching PSUs.
Technical Note: At the self-resonant frequency, XL = XC and Z ≈ ESR.

Figure 2: Impedance vs Frequency Characteristics- showing how impedance varies across the frequency spectrum for different capacitor values. It demonstrates impedance behavior across frequency spectrum for different ESR values.

Thermal Considerations and Performance Stability

Achieving consistent sub-10mΩ performance across temperature requires careful thermal management. The temperature coefficient of ESR in conductive polymer capacitors follows a different profile compared to liquid electrolyte designs.

The low temperature characteristics specification indicates impedance ratios of:

• Z(-25°C)/Z(+20°C) ≤ 1.15

• Z(-55°C)/Z(+20°C) ≤ 1.25 (at 100kHz)

This exceptional temperature stability ensures ESR performance remains predictable across the operating temperature range of -55°C to +105°C.

ESR Temperature Coefficient Analysis

Low Temperature Performance
Z(-25°C)/Z(+20°C) ≤ 1.15
Maximum 15% impedance increase at -25°C
Extended Low Temperature
Z(-55°C)/Z(+20°C) ≤ 1.25
Maximum 25% impedance increase at -55°C
Operating Temperature Range: -55°C to +105°C | Measurement Condition: 100kHz at specified temperatures

Figure 3: ESR Temperature Coefficient Analysis- demonstrating ESR variation across temperature range. The graph displays temperature stability per catalog specs: Z(-25°C)/Z(+20°C) ≤ 1.15 and Z(-55°C)/Z(+20°C) ≤ 1.25.

Series-Specific Performance Analysis
PXF Series: Lower ESR Architecture

The PXF series targets applications requiring ultra-low ESR with capacitance values from 120µF to 680µF and voltage ratings from 2V to 10V. The series achieves sub-10mΩ performance in multiple configurations:

  • 330µF/2.5V (F80): 10mΩ
  • 390µF/2.5V (F80): 10mΩ
  • 470µF/2.5V (F80): 9mΩ
  • 560µF/2.5V (F80): 9mΩ
  • 330µF/6.3V (F80): 9mΩ
  • 390µF/6.3V (F80): 9mΩ

The endurance specification of 15,000 hours at 105°C (3,000 hours for E40 and F46 case sizes) ensures long-term reliability in demanding applications.

PXJ Series: Enhanced Performance Platform

The PXJ series represents an evolutionary advancement, extending voltage ratings to 25V while maintaining ultra-low ESR performance. Key sub-10mΩ achievements include:

• 820µF/2.5V (F80): 7mΩ with 5,000mA ripple current

• 1,000µF/2.5V (F80): 7mΩ with 5,000mA ripple current

• 560µF/6.3V (F80): 8mΩ with 5,000mA ripple current

• 270µF/6.3V (F80): 8mΩ with 5,800mA ripple current

Capacitance vs ESR Performance Matrix

E61 (5×5.8mm)
Compact design
ESR: 22–45mΩ
F61 (6.3×5.8mm)
Balanced performance
ESR: 10–28mΩ
F80 (6.3×7.7mm)
Extended capacity
ESR: 7–24mΩ
H70 (8×6.7mm)
High capacity
ESR: 14–45mΩ
Performance Insight: F80 case size offers the best ESR-to-capacitance ratio for sub-10mΩ targets across PXF & PXJ.

Figure 4: Capacitance vs ESR Performance Matrix- comparing performance across different series and case sizes. The scatter plot showing ESR vs capacitance relationships with case size information.

PXS Series: Long-Life Ultra-Low ESR

The PXS series prioritizes extended operational life with 20,000 hours endurance at 105°C while maintaining competitive ESR performance. While not achieving sub-10mΩ values, the series provides ESR values from 22mΩ to 37mΩ with exceptional reliability characteristics.

The series utilizes the leakage current formula I = 0.2CV, where I represents maximum leakage current (µA), C is nominal capacitance (µF), and V is rated voltage (Vdc).

Design Optimization Strategies
PCB Layout Considerations

Achieving the full benefit of sub-10mΩ ESR requires meticulous PCB design. Parasitic inductance in PCB traces can significantly impact high-frequency performance. The recommended solder land dimensions provided in the catalog ensure optimal electrical and thermal connections:

For F80 case size (6.3mm × 7.7mm):

• Solder land dimensions: a=1.9mm, b=3.5mm, c=1.6mm

• Via placement restrictions apply beneath capacitor body

• Copper trace routing must avoid seal side proximity

PCB Layout Optimization Guidelines for Ultra-Low ESR Capacitors

Case Size Dimensions (D×L) Solder Land (a×b×c) Terminal Spacing (W) Pitch (P)
F616.3 × 5.8mm1.9 × 3.5 × 1.6mm0.5–0.8mm1.9mm
F806.3 × 7.7mm1.9 × 3.5 × 1.6mm0.5–0.8mm1.9mm
H708.0 × 6.7mm3.1 × 4.2 × 2.2mm0.7–1.1mm3.1mm
HC08.0 × 12.0mm3.1 × 4.2 × 2.2mm0.7–1.1mm3.1mm
✓ OPTIMAL LAYOUT
PXF F80
1–2mm clearance
Via placement OK
Wide traces

Best Practices

  • Maintain 1–2mm clearance from capacitor seal side
  • Use wide traces to minimize inductance
  • Place vias away from capacitor body
  • Follow recommended solder land dimensions
  • Avoid traces beneath capacitor
  • Use proper thermal relief for ground connections
✗ PROBLEMATIC LAYOUT
PXF F80
Too close to seal
Via under capacitor
Narrow traces
Small solder pads

Issues to Avoid

  • Traces too close to seal side
  • Narrow traces increasing inductance
  • Vias placed beneath capacitor body
  • Undersized solder land dimensions
  • Poor thermal management
  • Inadequate ground plane connections

Critical Design Considerations for Sub-10mΩ Performance

Parasitic Inductance Minimization: Every nH matters at high frequency. Use wide, short traces and solid ground returns.

Thermal Management: Ultra-low ESR allows high ripple; make sure copper pours and thermal vias handle the heat.

Manufacturing Tolerances: Follow solder-land specs for robust electrical/mechanical joints through reflow.

Figure 5: PCB Layout Optimization Guidelines- showing recommended solder land patterns and trace routing. The visual comparison of optimal vs problematic layouts with exact solder land dimensions from catalog.

Ripple Current and Thermal Management

Ultra-low ESR enables exceptional ripple current handling, but thermal management becomes critical. The relationship between ripple current and internal temperature rise follows:

ΔT = (Irms/Irated)² × ΔTrated

Where ΔTrated represents the temperature rise at rated ripple current. The PXF series demonstrates ripple current capabilities exceeding 4,000mA in multiple configurations, enabling high-power applications.

Thermal Rise vs Ripple Current Analysis

ΔT = (Ix/Io)² × ΔTo
Where: ΔT = Temperature Rise, Ix = Operating Current, Io = Rated Current, ΔTo = Rated Temperature Rise
Series Capacitance/Voltage Case Size ESR (mΩ) Rated Ripple Current (mA) Power Dissipation (mW)
PXJ820µF/2.5VF8075,000175
PXJ1000µF/2.5VF8075,000175
PXJ270µF/6.3VF8085,800269
PXF330µF/6.3VF8094,200159
PXF470µF/2.5VF8094,200159
PXS390µF/6.3VH70223,220228

Ultra-Low ESR Advantage

Sub-10mΩ ESR reduces power dissipation, enabling higher ripple with minimal thermal rise.

Thermal Design Margin

Use 50–70% derating of max ripple current for long-term reliability.

Lifetime Impact

~10°C lower operating temperature ≈ 2× lifetime (Arrhenius relation).

Frequency Considerations

Apply ripple current multipliers vs actual switching frequency; 100kHz is baseline.

Critical Insight: PXJ achieves ~175 mW at 5 A ripple with 7 mΩ ESR—~60% improvement vs conventional aluminum electrolytics.

Figure 6: Thermal Rise vs Ripple Current Analysis- showing temperature rise characteristics under various loading conditions. The chart exhibits thermal performance curves and power dissipation calculations for different ESR values.

Application Engineering Considerations
High-Frequency Switching Power Supplies

Sub-10mΩ ESR capacitors excel in high-frequency switching applications where traditional capacitors introduce excessive losses. The frequency multiplier table indicates performance optimization across the spectrum:

• 120Hz: 0.05 multiplier

• 1kHz: 0.30 multiplier

• 10kHz: 0.55 multiplier

• 50kHz: 0.70 multiplier

• 100kHz-500kHz: 1.00 multiplier (rated condition)

Voltage Regulation and Transient Response

Ultra-low ESR directly improves voltage regulation and transient response in power management applications. The impedance reduction enables faster response to load changes and reduces voltage ripple in switching regulators.

Surge Voltage Handling

The surge voltage specifications demonstrate robust overvoltage capability:

• 2.5V rated: 2.9V surge capability

• 6.3V rated: 7.2V surge capability

• 10V rated: 12V surge capability

• 16V rated: 18V surge capability

Reliability and Qualification Standards
Endurance Testing Protocols

The endurance specifications define performance expectations under accelerated aging conditions. At 105°C with rated voltage applied for the specified duration:

• Capacitance change: ≤±20% of initial value

• ESR: ≤150% of initial specified value

• Leakage current: ≤initial specified value

Environmental Stress Testing

Bias humidity testing at 85°C, 85% RH validates performance under harsh environmental conditions. The specifications require:

• Capacitance change: ≤±30% of initial value

• ESR: ≤200% of initial specified value

Future Considerations and Technology Roadmap

The progression from PXF to PXJ series demonstrates continuous advancement in conductive polymer technology. The voltage range extension from 10V to 25V while maintaining sub-10mΩ performance indicates ongoing materials science improvements.

The integration of vibration-resistant terminal structures (Terminal Code: G) for automotive applications shows the technology's expansion into demanding environments requiring 30G vibration resistance.

Conclusion

Achieving sub-10mΩ ESR performance in surface mount capacitors requires the convergence of advanced materials science, precision manufacturing, and application-specific design optimization. Nippon Chemi-Con's PXF and PXJ series demonstrate that conductive polymer technology can deliver unprecedented performance levels while maintaining the reliability and cost-effectiveness required for volume production.

The technology enables new possibilities in high-efficiency power conversion, ultra-fast transient response systems, and compact high-power designs previously constrained by ESR limitations. As power density requirements continue to increase, ultra-low ESR capacitor technology will play an increasingly critical role in next-generation electronic system design.

Leveraging SAGA Components and Nippon Chemi-Con

Navigating the complexities of ultra-low ESR capacitor selection, thermal management, and high-frequency design requires expertise. At SAGA Components, our team of application engineers, backed by strong relationships with partners like Nippon Chemi-Con, provides crucial support. We help you:

• Translate system requirements into optimal capacitor specifications and ESR targets.

• Compare Nippon Chemi-Con conductive polymer solutions against alternatives, highlighting performance and reliability benefits.

• Provide samples for prototyping and validation of critical switching applications.

• Manage logistics and supply chain requirements for volume production across Nordic markets.

Our deep technical expertise in conductive polymer technology, thermal management, and high-frequency circuit design enables us to assist at every stage of your design process—from initial concept through production. By partnering with SAGA Components and leveraging Nippon Chemi-Con's comprehensive NPCAP™ portfolio, you can develop robust, efficient, and cost-effective solutions for even the most demanding power management applications.

Contact SAGA Components:

📧 Email: contact@sagacomponents.com

📞 Phone: +46 (0) 8 564 708 00

🌐 Web: https://www.sagacomponents.com

Download Resources:

• NPCAP™ Technical Selection Guide: https://www.chemi-con.co.jp/en/download/

• Lifetime Calculation Software Tool: https://www.chemi-con.co.jp/en/tool/lifetime/detail.html

• Full product catalog download: https://www.chemi-con.co.jp/en/download/

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