Technical upgrade & supply security · HVRGXP expert-grade answer to KOA RK92 EOL

Executive Summary

In the fields of new energy, industrial high-voltage power supplies, medical imaging (CT/X-Ray), and smart grids, SIP (Single In-line Package) high-voltage thick film resistors serve as a critical line of defense for ensuring system safety. For a long time, Japan's KOA RK92 series defined the industrial standard in this domain. However, with Japanese manufacturers adjusting their production capacity strategies, the RK92 series has entered its End-of-Life (EOL) phase, posing a severe supply chain disruption risk to global high-end equipment manufacturers relying on this model.

HVC Company, leveraging its profound expertise in high-voltage thick film technology, has launched the HVRGXP series, specifically designed to fill this market gap. Unlike ordinary imitations on the market, HVC employs unique non-inductive serpentine printing technology and a 96% high-purity alumina substrate. This not only achieves Pin-to-Pin compatibility with KOA RK92 in terms of dimensions and leads but also delivers an "expert-grade" performance leap in high-frequency pulse response, long-term stability, and customization flexibility, making it an ideal solution for the RK92 EOL crisis.

At-a-glance benchmark: KOA RK92 vs HVC HVRGXP

Electrical specification comparison (datasheet-level)

The table below aligns with the same head-to-head layout used on HVC’s RK92 replacement product pages, summarizing key electrical limits engineers validate first during re-qualification.

1. Introduction: The "Gray Rhino" of High-Voltage Component Supply Chains

With the rapid advancement of power electronics technology, the demand for high-voltage components in modern industrial systems is evolving towards higher voltage, stronger pulse capability, and more stable supply.

1.1 Technical Background: The Critical Role of High-Voltage Resistors

High-voltage thick film resistors perform core tasks in circuits such as voltage division sampling, high-energy discharge, and surge suppression. Engineers' pain points focus on: * Voltage Withstand Limit: How to achieve higher creepage distance and voltage ratings within a limited volume? * Pulse Impact: How to ensure the film layer does not experience instantaneous thermal breakdown under lightning strikes or switching surges? * Supply Chain Resilience: When the original manufacturer (e.g., KOA) announces EOL, is there a reliable alternative?

1.2 Current Situation: The Impact of KOA RK92 EOL

The KOA RK92 series was once the benchmark in this field, but as it approaches the end of its lifecycle, lead times have extended to over 30 weeks and new orders are no longer accepted. For medical and industrial control equipment with lifecycles exceeding 10 years, finding a product that offers both Pin-to-Pin replacement and long-term stable supply has become an urgent priority.

Lifecycle snapshot (public roadmap–style risks)

Use this as a procurement checklist; always confirm the latest factory notice for your exact RK92 sub-type.

2. In-depth Technical Analysis: Evolution from "General" to "Expert-Grade"

The HVC HVRGXP series is not a simple reverse-engineered imitation but a profound upgrade based on material science and structural design.

2.1 Core Design: Non-Inductive Serpentine Printing

Most ordinary high-voltage resistors use simple line printing, resulting in larger parasitic inductance. * HVC Expert-Grade Process: The HVRGXP series adopts computer-optimized non-inductive serpentine printed circuits. By precisely calculating the mutual inductance cancellation of current paths, parasitic inductance is reduced to the microhenry (µH) level. * Application Value: In high-frequency switching power supplies and pulse modulation circuits, it maintains pure resistive characteristics, prevents waveform oscillation, and protects subsequent precision components.

2.2 Material Innovation: 96% Alumina Substrate and Ruthenium-based Paste

• Substrate Upgrade: All series come standard with a 96% high-purity alumina (Al₂O₃) substrate, which has a thermal conductivity 30% higher than ordinary 85% alumina substrates. This means lower hot spot temperatures for the resistor under high-voltage loads and less long-term drift.
• Film Formulation: Utilizes high-grade ruthenium oxide paste, combined with a special glass-phase sintering process, resulting in an extremely low Voltage Coefficient of Resistance (VCR) (< 5 ppm/V), ensuring sampling linearity across the full range from low to high voltage.

2.3 Protection Upgrade: Vacuum Epoxy Encapsulation

• Insulation Assurance: Unlike simple dipping processes, HVC employs high-density epoxy resin vacuum encapsulation (Conformal Coating), eliminating air bubbles and pinholes. The product has passed rigorous Double 85 tests (85℃/85%RH), effectively preventing surface flashover even in outdoor high-humidity or high-altitude environments.

2.4 HVRGXP naming vs. mechanical family (quick decoder)

HVC model suffixes map to ceramic body length (mm-class) so that pin spacing and creepage track the original KOA outline you are replacing.

Cross-reference quick guide (representative examples)

Same style as the “quick guide” tables on the RK92 replacement hub pages—use for desk checks before the full Pin-to-Pin list in §3.

3. Practical Comparison: KOA RK92 vs HVC HVRGXP Precise Replacement Table

To ensure a seamless transition, HVC engineers have compiled the following Pin-to-Pin replacement list for key models. The HVC HVRGXP series fully covers KOA's different size specifications, including 9.6mm (small), 26mm (medium), and 30mm (large).

> Note: The suffixes in HVC models (e.g., 7.26, 5.10) represent the physical dimensions of the substrate, ensuring that the mounting hole spacing is exactly the same as the original KOA product.

Extended RK92 → HVC matrix (same block as Style 5 FAQ & product hub)

Seven-column lookup: power, resistance, tolerance, TCR, body outline, and HVC family code—pulled from the same KOA RK92 cross-reference used in our Style 5 English FAQ and aligned with the product article KOA RK92 replacement (2). Rows here extend beyond the narrative Pin-to-Pin list above.

Note: HVRGXP codes denote the substrate / mechanical family for pin-to-pin fit. Verify against your BOM and the latest datasheet.

4. Why Choose HVC? Strategic Value Beyond "Replacement"

When facing the EOL of KOA RK92, choosing HVC is not just about solving an immediate problem; it's a strategic upgrade for your supply chain.

4.1 Addressing the Customization Pain Point of "Non-Standard Resistance Values"

Before EOL, KOA focused on standard E24 resistance values, and many non-standard values were already out of stock. * HVC Solution: Relying on its own thick film printing production lines and laser trimming technology, HVC can produce resistors of any resistance value (e.g., 123MΩ or 4.56GΩ) for you, with extremely low Minimum Order Quantity (MOQ), flexibly meeting the maintenance needs of older equipment and new R&D requirements.

4.2 Addressing the Fundamental Pain Point of "EOL and Supply Disruption"

• HVC Solution: The HVRGXP series is an HVC Long-term Availability product. We commit to long-term stable supply, with standard lead times of only 4-6 weeks (expedited orders can be requested for 2 weeks), completely eliminating EOL anxiety.

4.3 Supply & program comparison (typical commercial envelope)

5. Conclusion: From Reactive to Proactive, Rebuilding Supply Chain Security

The EOL of KOA RK92 is a certainty. Continuing to search for accumulated inventory is not only costly but also carries quality risks such as lead oxidation and poor solderability.

By choosing the HVC HVRGXP series, you gain more than just a resistor of the same size; you secure a long-term stable supply commitment and expert-level technical support.

In the face of the EOL crisis, HVC is your most reliable "Plan B" and "Ultimate Solution."

Initiate Replacement Verification Now

Please send us your specific KOA RK92 model, and HVC's senior engineers will provide you with a Pin-to-Pin comparison solution and free samples within 24 hours.

• Global Sales & Technical Inquiry: sales@hv-caps.com
• HVC High Voltage Resistor Product Center: https://www.hv-caps.com/products/High-Voltage-resistor-Flat-Style.html

Copyright © 2026 HVC Company. KOA and RK92 mentioned herein are registered trademarks of their respective holders, and this document is for technical compatibility and alternative selection purposes only.