• (Peak Succession & Technical Superiority: Defining the Engineering Replacement Standard for Murata's Discontinued HV Ceramic Capacitors)

1. Executive Summary

Over the past three decades, Japan's Murata (Murata Manufacturing Co., Ltd.) DHS series (bolt-type/doorknob-type) and DHR series (radial lead-type) high-voltage ceramic capacitors have defined the passive component standards for global high-end medical imaging (CT/X-Ray), industrial non-destructive testing (NDT), and precision high-voltage power supply industries, thanks to their excellent voltage withstand margin, low dielectric loss, and high-frequency stability. However, with Murata's announcement in 2018 to discontinue its entire high-voltage ceramic capacitor product line (covering 2kV to 50kV), the global supply chain faced an unprecedented "supply disruption" crisis.

For equipment manufacturers, finding a replacement that achieves Pin-to-Pin compatibility in electrical performance, mechanical dimensions, safety certifications, and long-term reliability became an urgent priority for engineering and procurement departments. HVC Capacitor, with over two decades of deep expertise in high-voltage passive components, quickly filled this market vacuum. HVC not only provided physical replacement solutions for Murata's discontinued models but also achieved technical superiority in voltage withstand ratings (extended to 100kV) and high-frequency loss control, utilizing its independently developed N4700 (Class I) ceramic dielectric technology. This white paper will deeply analyze how HVC assists global high-end manufacturing enterprises in rebuilding a secure, diversified, and high-performance supply chain system.

1. Benchmarking Background: Focusing on the "Succession to the Throne" in High-Voltage Field

2.1 Technical Logic Behind Murata's Discontinuation

Murata's discontinuation was not due to technological obsolescence, but rather an extreme focus based on its global business strategy—concentrating resources on high-growth, standardized electric vehicle (EV) and 5G communication MLCC (Multilayer Ceramic Capacitor) markets.

In contrast, high-voltage plug-in ceramic capacitors (DHS/DHR series) belong to a typical market characterized by "high technical barriers, multiple varieties, and small to medium batch sizes." These products require special Strontium Titanate base materials, complex vacuum epoxy encapsulation processes, and stringent high-voltage partial discharge tests. Murata's exit left a significant technical and market vacuum.

2.2 HVC's Strategic Positioning

HVC Capacitor's core strategy is very clear: We do not compete with Murata in the MLCC market; instead, we precisely take over and upgrade the high-voltage plug-in/bolt capacitor segment that they actively abandoned.

HVC's goal is to provide the sole qualified successor and upgrader for the following two "legacy" series:

1. DHS Series (Doorknob Type): Cylindrical bolt structure, voltage withstand 20kV-50kV, a core component for CT machine oil tanks and high-power lasers.
2. DHR Series (Radial Lead Type): Disc-shaped lead structure, voltage withstand 3kV-15kV, a standard component for industrial static electricity, negative ion, and flaw detection equipment.

1. Technical Deep Dive

To demonstrate the feasibility and superiority of the "replacement," we will meticulously break down HVC's mass production technology against Murata's original datasheet specifications.

3.1 Dielectric Material: The Ultimate Contest of N4700

The soul of Murata's high-voltage capacitors lies in its ceramic dielectric, code-named "ZM" (i.e., the industry-standard N4700 Class I dielectric). This is the foundation for high-frequency, high-voltage applications.

• Murata (Original "ZM" Dielectric):

• Dissipation Factor (DF): Nominal le 0.2%.

• Temperature Characteristics: Capacitance change rate is approximately pm 30% within the -20℃~+85℃ range (actual performance is excellent).

• Limitations: Under extremely high-frequency pulses, Murata's standard products have relatively conservative self-heating control.

• HVC (Upgraded N4700 Dielectric):

• Dissipation Factor (DF): le 0.1% sim 0.2%.

• Technical Analysis: HVC uses an improved strontium titanate formula, resulting in a lower Equivalent Series Resistance (ESR) for capacitors in high-frequency voltage multiplier circuits (20kHz-100kHz). This means that under the same ripple current, HVC capacitors exhibit lower self-heating.

• Engineering Value: This is crucial for CT machine capacitors enclosed in oil-filled tanks, as the tank's heat dissipation capacity is limited, and lower heat generation directly translates to a longer overall machine lifespan.

• Temperature Stability: HVC's N4700 is a temperature-compensating ceramic, with capacitance change rate controlled within pm 5% across the entire temperature range, significantly outperforming Murata's nominal Y5T/Z5U class specifications, ensuring the precision of high-voltage output.

3.2 Voltage Rating: A Leap from 50kV to 100kV

Murata's product line design primarily served medical and industrial standards prior to 2010, while HVC has expanded its technology to meet future ultra-high voltage demands.

• Murata (Before Discontinuation):

• Voltage Ceiling: Typically capped at 40kV - 50kV (e.g., DHS4E4G series).

• Limitations: For ultra-high voltage applications of 60kV-100kV (e.g., particle accelerators, Marx generators, smart grid damping), Murata lacked standard product support. Customers often had to connect multiple capacitors in series, leading to bulky designs and reduced reliability.

• HVC (Current Technology):

• Voltage Ceiling: Mass production capability extends to 100kV.

• Technical Breakthrough: HVC employs a unique Internal Series Construction. This involves forming multiple internally series-connected capacitor units within a single ceramic cylinder through a special electrode stacking process. This structure significantly disperses the electric field stress on a single dielectric layer.

• Advantages: HVC can provide a higher voltage withstand safety factor (e.g., 60kV or 80kV) than Murata within the same 60mm diameter volume, without the need for external series connection.

3.3 Mechanical Structure: Pin-to-Pin Precision Replication

The biggest obstacle to replacement is often mechanical dimensions. Even a 1mm deviation in capacitor size can lead to creepage or installation interference inside a high-voltage oil tank. HVC invested heavily in developing molds that are completely identical to Murata's.

• Bolt-Type (Doorknob):

• Diameter Matching: HVC perfectly replicated Murata's 20mm, 30mm, 38mm, 45mm, 60mm standard diameters.

• Terminal Matching: Murata offered both metric (M4/M5/M6) and imperial (UNF 10-32) thread standards. HVC provides a full range of corresponding options, meaning maintenance engineers can directly screw on HVC capacitors without needing to replace the high-voltage oil tank's copper busbars or structural components.

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• Radial Lead Type (Radial):

• Lead Pitch: Strictly matches Murata's 7.5mm, 9.5mm, 10mm, 12.5mm standard.

• Encapsulation Material: Uses the same blue or black epoxy resin powder encapsulation, complying with UL94V-0 flame retardant standard, and possessing excellent moisture resistance.

3.4 PD & Reliability

Under high voltage, Partial Discharge (PD) is the culprit behind ceramic capacitor failure. Tiny internal air bubbles ionize under high voltage, gradually eroding the ceramic dielectric, ultimately leading to breakdown.

• Murata: As an industry benchmark, its PD control is exceptionally good.
• HVC:

• Process Benchmarking: HVC introduced X-Ray fluoroscopy inspection and ultrasonic scanning at the same level as Murata, ensuring no voids or delaminations inside the ceramic body.

• Measured Data: In AC partial discharge tests at 1.5 times the rated voltage, HVC's N4700 capacitors' PD level is controlled to < 5pC (picocoulombs). This indicator fully meets the stringent requirements for medical-grade CT, ensuring no hidden damage under high-voltage loads.

1. Cross Reference for Typical Models

The following comparison is entirely based on Murata DHS/DHR discontinued datasheets and HVC measured specifications, covering three core scenarios: medical, industrial, and scientific research.

4.1 Bolt-Type (DHS Series) — Core Components for CT/X-Ray Machines

These capacitors are used in 80kV-140kV high-voltage generator voltage multiplier circuits, with extremely high requirements for size and thread precision.

4.2 Radial Lead Type (DHR Series) — Industrial High-Voltage Modules

These capacitors are used in handheld devices or compact high-voltage sources, sensitive to lead pitch and encapsulation insulation.

1. Quality Control & Market Validation

5.1 Rigorous Testing Procedures

To ensure reliability after replacing Murata, HVC implements QA procedures that are even more rigorous than industry standards:

• 100% Partial Discharge Test: Ensures every N4700 capacitor has no hidden defects under high voltage.
• Pulse Endurance Test: Simulates X-ray machine arcing conditions, enduring 100,000 charge-discharge cycles with capacitance decay < 3%.
• Double 85 Test (85℃/85%RH): Verifies the insulation performance of epoxy encapsulation in extreme humid and hot environments.

5.2 Endorsement from Top Global Customers

HVC's replacement solutions have been validated and mass-produced by numerous Fortune 500 companies worldwide:

• Medical Imaging: HVC has become a qualified supplier of core components for high-voltage generators in CT and X-ray machine projects for GE Healthcare, Philips, Siemens Healthineers, and leading domestic medical imaging enterprises.
• Industrial Non-Destructive Testing: Japanese companies such as Nikon (Industrial CT) and Shimadzu have also begun integrating HVC products into their supply chains to address the risks posed by Murata's discontinuation.
• Cutting-Edge Scientific Research: ABB's smart grid equipment and various university physics laboratories (e.g., Marx generators) extensively use HVC's 100kV ultra-high voltage capacitors.

1. Conclusion: HVC is the Legitimate Heir to Murata's High-Voltage "Legacy"

Murata did not discontinue the DHS/DHR series due to technological obsolescence, but rather due to a strategic transformation (focusing on MLCCs). The technical void left by this decision can only be filled by HVC Capacitor, which specializes in high-voltage ceramic capacitors.

• If you need MLCCs: Please continue to choose Murata; they remain the king in the low-voltage field.
• If you need DHS/DHR high-voltage plug-in/bolt capacitors: HVC is not just a replacement but also a technological upgrader. With N4700 dielectric, 100kV capability, and Pin-to-Pin compatibility, we have proven that where Murata exited, HVC has established a new industry standard.

1. Contact & Technical Support

• *Reject "magic modifications," choose "original-grade replacement."** HVC's engineering team is ready to provide precise cross-referencing services and free sample testing for Murata's discontinued models.

• Technical Support & Sales Email: sales@hv-caps.com">sales@hv-caps.com
• Official Website: www.hv-caps.com

Most Inquiry Alternative Items

For Murata End-of-Life (EOL) items, inquiry for HVC's Part Number and datasheet/quotation/sample:

DHR Series Cross Reference

DHS Series Cross Reference