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N4700 vs Y5T Dielectric Ceramic Material for High-Voltage Capacitors

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Key Takeaway: Choosing the right dielectric material — N4700 or Y5T — directly determines the reliability, lifespan, and cost of high-voltage ceramic capacitors. This guide explains the critical differences in insulation resistance, dissipation factor, temperature stability, and real-world application suitability, helping engineers make informed material selection decisions.

Why Dielectric Material Matters in High-Voltage Ceramic Capacitors

High-voltage ceramic disc capacitors are critical components in X-ray power supplies, CO2 laser systems, Marx pulse generators, medical imaging equipment, and industrial non-destructive testing (NDT) systems. The dielectric material inside these capacitors governs every aspect of performance — from voltage withstand capability and frequency response to long-term thermal stability and failure rate.

Among the many ceramic dielectric classifications, N4700 (DL type) and Y5T (D type) represent two widely adopted choices in the high-voltage capacitor market. While both serve high-voltage applications, their electrical characteristics, temperature behavior, and cost structures differ significantly — and choosing the wrong material can lead to premature capacitor failure, excessive heating, or system-level reliability issues.

This article provides a comprehensive, side-by-side technical comparison of N4700 and Y5T dielectric materials, covering insulation resistance, dissipation factor, temperature coefficient, frequency response, and real-world application scenarios — with data-backed recommendations for electronic engineers and procurement professionals.

N4700 vs Y5T: Complete Technical Comparison Table

The following table presents a direct comparison of all critical parameters between N4700 and Y5T dielectric materials, alongside Y5U and Y5V for reference:

Parameter	N4700 (DL)	Y5T (D)	Y5U (E)	Y5V (F)
IEC Classification	Class 1 (DL)	Class 2 (D)	Class 2 (E)	Class 2 (F)
Operating Temperature Range	-25°C to +85°C (extended: -40°C to +105°C)	-25°C to +85°C	-25°C to +85°C	-25°C to +85°C
Insulation Resistance (min)	≥200,000 MΩ	≥100,000 MΩ	≥10,000 MΩ	≥10,000 MΩ
Dissipation Factor (max)	≤0.2%	≤1.0%	≤2.0%	≤2.0%
Capacitance Temperature Coefficient	±28% (-40~+105°C: ±33%)	+22% / -33%	+22% / -56%	+22% / -80%
Rated Voltage Range	1 kV – 50 kV	1 kV – 40 kV	1 kV – 30 kV	1 kV – 30 kV
Max Frequency Suitability	≥100 kHz	≤50 kHz	Low frequency only	Low frequency only
Pulse Discharge Capability	Excellent	Limited	Poor	Poor
Strontium Titanate Content	High (proprietary formula)	Moderate	Low	Low
Relative Cost	Highest	Moderate	Low	Lowest

N4700 (DL Type): Premium Dielectric for Demanding Applications

Electrical Performance Advantages

N4700 (also designated as DL type under Chinese national standards) is a Class 2 ceramic dielectric material specifically engineered for high-voltage, high-frequency, and pulse applications. Its key electrical characteristics include:

Insulation Resistance ≥200,000 MΩ — This is 2× that of Y5T and 20× that of Y5U/Y5V. Higher insulation resistance directly translates to lower leakage current and greater overcurrent capability, which is critical in high-voltage power supply circuits where even microamps of leakage can cause thermal runaway.
Dissipation Factor ≤0.2% — Five times lower than Y5T (1%) and ten times lower than Y5U/Y5V (2%). The dissipation factor (tan δ) determines how much energy is lost as heat during each charge-discharge cycle. At high frequencies, a high dissipation factor causes rapid temperature rise, leading to capacitance drift and eventual dielectric breakdown.
Frequency Response up to 100 kHz+ — N4700 maintains stable capacitance and low loss at frequencies well above 100 kHz, making it suitable for switching-mode power supplies (SMPS), high-frequency ballasts, and pulsed power systems.
Excellent Pulse Discharge Capability — The low dissipation factor and high insulation resistance enable N4700 capacitors to handle fast charge-discharge cycles without excessive internal heating — a critical requirement in Marx generators, laser excitation circuits, and medical X-ray pulse systems.

Temperature Stability

N4700 exhibits a capacitance temperature coefficient of approximately ±28% over the -25°C to +85°C range, and ±33% when extended to -40°C to +105°C. While this is a Class 2 material (not as stable as Class 1 NP0/C0G types), it provides significantly better thermal stability than Y5T (+22%/-33%), Y5U (+22%/-56%), and Y5V (+22%/-80%). This means capacitance remains more predictable across the operating temperature range, reducing the risk of circuit detuning or resonance shift in sensitive applications.

Y5T (D Type): Cost-Effective Solution for Standard Applications

Performance Profile

Y5T (D type) is a mid-range ceramic dielectric that offers a practical balance between cost and performance. It is widely used in applications where the extreme frequency or pulse performance of N4700 is not required, but where Y5U/Y5V materials would be inadequate:

Insulation Resistance ≥100,000 MΩ — Half of N4700 but still 10× better than Y5U/Y5V. Sufficient for most standard high-voltage DC power supply applications.
Dissipation Factor ≤1.0% — Five times higher than N4700, which limits Y5T to lower-frequency applications (typically below 50 kHz). Above this frequency, the dielectric loss generates enough heat to cause capacitance drift and potential thermal failure.
Operating Frequency ≤50 kHz — Y5T is well-suited for DC high-voltage power supplies, LED driver circuits, automotive electronics (air conditioning controllers, infotainment systems), and general-purpose filtering applications where frequencies remain moderate.
Maximum Capacitance up to 3,300 pF — Y5T offers higher dielectric constant than N4700, allowing larger capacitance values in a given package size. For example, the 15 kV 3,300 pF Y5T disc capacitor is one of the most popular configurations for cost-sensitive high-voltage generator designs.

Limitations to Consider

Y5T should not be used in:

Pulse discharge circuits — The higher dissipation factor causes excessive heating during rapid charge-discharge cycles, leading to accelerated degradation.
High-frequency applications (>50 kHz) — Capacitance attenuation and loss increase dramatically above the rated frequency range.
Continuous high-temperature operation — While rated for -25°C to +85°C, Y5T should not be operated near the upper temperature limit for extended periods without derating.
Mission-critical medical or military systems — Where reliability requirements demand the superior insulation and loss characteristics of N4700.

Application Guide: Which Material Should You Choose?

Application Scenario	Recommended Material	Reason
Medical X-ray / CT power supplies	N4700	High reliability, low loss, pulse capability required
CO2 laser excitation circuits	N4700	Fast pulse discharge, high-frequency operation
Marx generators / pulsed power	N4700	Requires low DF for rapid charge-discharge cycles
Industrial NDT / flaw detection	N4700	Stable performance, high-voltage withstand up to 50 kV
Security screening equipment	N4700	Continuous operation demands low thermal drift
Military / aerospace systems	N4700	Maximum reliability, extended temperature range
Cost-effective HV generators (<50 kHz)	Y5T	Good balance of performance and cost
LED driver circuits	Y5T	Moderate frequency, cost-sensitive application
Automotive electronics	Y5T	Sufficient for AC controllers, infotainment filtering
South Asian market cost-optimized designs	Y5T	Replaces inferior Y5U/Y5V with significantly better performance

Why You Should Avoid Y5U and Y5V for High-Voltage Applications

Some manufacturers offer capacitors using Y5V or Y5U materials because of their extremely low raw material cost. However, the performance trade-offs are severe:

Insulation Resistance only 10,000 MΩ — 20× lower than N4700. This means 20× higher leakage current, which generates internal heat and accelerates aging.
Dissipation Factor of 2% — 10× higher than N4700. At even moderate frequencies, this causes rapid temperature rise and capacitance instability.
Temperature Coefficient up to -80% (Y5V) — Capacitance can drop by 80% at the temperature extremes, essentially rendering the capacitor non-functional in harsh environments.
Real-world failure case: A customer reported that 35 kV Y5V capacitors (2,200-2,500 pF, 16-25 mm diameter) from a low-cost supplier began failing within one month of operation in a high-voltage generator. After switching to N4700 material capacitors, the system achieved stable long-term operation.

Frequently Asked Questions

Q1: Can Y5T capacitors be used as a direct replacement for Y5U or Y5V?

Yes. Y5T is a drop-in replacement that offers significantly better insulation resistance (10× vs Y5U/Y5V) and lower dissipation factor (1% vs 2%). Customers who switch from Y5U/Y5V to Y5T consistently report lower dissipation factor values and improved system reliability. However, note that Y5T has a slightly lower maximum capacitance than Y5V — consult with HVC engineering for specific capacitance requirements.

Q2: What is the maximum frequency at which Y5T capacitors can operate reliably?

Y5T capacitors should be limited to applications below 50 kHz. Above this frequency, the dissipation factor causes excessive dielectric heating, leading to capacitance drift and potential thermal failure. For applications requiring frequencies above 100 kHz, N4700 material is strongly recommended.

Q3: Why is N4700 material more expensive than Y5T?

N4700 contains a higher proportion of strontium titanate and uses proprietary formulas that are often patent-protected. The manufacturing process requires tighter quality control to achieve the superior insulation resistance (200,000 MΩ) and lower dissipation factor (0.2%). For high-end applications in medical, military, and aerospace sectors, the performance premium justifies the cost. For cost-sensitive applications below 50 kHz, Y5T provides an excellent balance.

Q4: Can N4700 capacitors handle continuous pulse discharge operations?

Yes. N4700 is specifically designed for pulse applications. Its extremely low dissipation factor (0.2%) means minimal energy is lost as heat during each charge-discharge cycle, and its high insulation resistance (200,000 MΩ) ensures low leakage current. This makes N4700 the preferred choice for Marx generators, laser excitation circuits, medical X-ray pulse power supplies, and similar high-demand applications.

Q5: What voltage range do HVC's N4700 and Y5T capacitors cover?

HVC offers high-voltage ceramic disc capacitors in both N4700 and Y5T materials covering a voltage range from 1 kV to 50 kV. Capacitance values range from 10 pF to 10,000 pF. Custom specifications are available upon request. Contact the HVC sales engineering team for specific part numbers and datasheets.

Y5T Material: Technical Quick Reference for Design Engineers

For engineers evaluating Y5T material for their high-voltage capacitor designs, the following specifications provide a quick reference:

Specification	Value
Operating Voltage Range	100 V – 40 kV DC
Operating Temperature Range	-30°C to +85°C
Frequency Range	1 kHz – 10 kHz (max recommended: 50 kHz)
Maximum Capacitance	Up to 3,300 pF
Polarization	Non-polar
Plate Resistance	>10,000 MΩ
Insulation Resistance (at 500 VDC)	≥100,000 MΩ
Dissipation Factor (tan δ)	≤0.5% (typical: ≤1%)
Capacitance Tolerance	±10%, ±20%, +80/-20%
Dielectric Strength (Test Voltage)	200% of rated voltage

HVC Recommendation

For high-voltage generator manufacturers and procurement engineers:

Choose N4700 when your application involves frequencies above 50 kHz, pulse discharge, continuous high-voltage operation, or mission-critical reliability requirements (medical, military, aerospace).
Choose Y5T for cost-optimized designs operating below 50 kHz, where moderate performance is sufficient and budget constraints are a primary consideration.
Avoid Y5U/Y5V for any high-voltage application — the long-term cost of field failures far outweighs the initial material savings.