Executive Summary

In high-voltage detection, impedance matching, and high-energy discharge circuits, flat (SIP) high-voltage thick film resistors are critical because of their voltage withstand and compact footprint. For many years, KOA Corporation’s RK92 series has been the de facto standard. As Japanese suppliers adjust capacity, the RK92 line has reached end of life (EOL), leaving legacy equipment hard to repair and new designs without a clear path to qualification.

Drawing on deep experience in high-voltage materials, HVC developed the HVRGXP series to close that gap. Unlike generic lookalikes, HVC uses non-inductive serpentine printing and a 96% high-purity alumina substrate, achieving pin-to-pin compatibility with KOA RK92 while improving high-frequency pulse behavior and long-term stability.

1. Core Technology: From “General Purpose” to Expert Grade

The KOA RK92 is a capable general-purpose part, but generic design can limit modern HV systems (e.g. high-frequency X-ray sets, precision HV supplies). HVRGXP advances on three axes:

1.1 True Non-Inductive Design

Under nanosecond-scale HV pulses, parasitic inductance in ordinary thick-film parts distorts waveforms.

• HVC technical strengths: HVRGXP uses a serpentine non-inductive print pattern; mutual cancellation of current paths holds parasitic inductance to roughly microhenry levels.
• Application benefits: Suited to high-frequency switch-mode supplies and pulse-modulation circuits, staying resistive at RF and avoiding inductive artifacts.

1.2 Specific Energy and Surge Withstand

HV rails see fast transients; ordinary films can fail on overload.

• HVC technical strengths: High-grade ruthenium oxide ink on a 96% Al₂O₃ substrate yields strong heat spreading and film adhesion.
• Performance gain: Pulse energy handling is improved versus same-size alternatives, reducing open-circuit risk under ESD or lightning-induced surges.

1.3 Very Low Voltage Coefficient (VCR)

HV resistors drift slightly with applied voltage (VCR).

• HVC technical strengths: Particle microstructure is tuned so VCR is typically < 5 ppm/V, supporting HV dividers and precision sense networks with stable readings from 100 V to 10 kV.

2. Precise Benchmarking: KOA RK92 and HVC HVRGXP

HVRGXP maintains full compatibility with KOA RK92 on body size (SIP), lead pitch, and power ratings—supporting straightforward replacement evaluation in engineering.

2.1 Practical replacement table for common models

Table values reflect published ratings. HVRGXP spans typical KOA lengths (9.6 mm, 26 mm, 30 mm, etc.):

Note: Numeric suffixes such as 7.26 or 5.10 denote mechanical size families so mounting stays aligned with the original part.

3. Why choose HVC as your EOL replacement partner?

Addressing RK92 discontinuation is not only about a part that merely “works”; it is about long-term availability and room to improve.

3.1 Mitigating shortage and grey-market risk

RK92 is in late life; new factory orders are gone and broker stock is expensive, aged, and sometimes harder to solder.

• HVC solution: HVRGXP is on a long-life product plan. Standard lead time is typically 4–6 weeks, with a roadmap aimed at predictable availability.

3.2 Custom non-standard resistance

KOA focused on standard E24 spreads; many specials are already unobtainable.

• HVC solution: In-house thick-film printing and laser trimming support arbitrary resistance values (e.g. 123 MΩ, 4.56 GΩ) with practical MOQs for repair and new design.

3.3 Insulation and Coating Quality

HVC transfers HV insulation process knowledge into the resistor line.

• HVC solution: High-grade epoxy conformal encapsulation limits voids and pinholes, supporting humid or altitude-stressed installations without surface flashover.

4. Conclusion: Turn EOL into an Upgrade

RK92 discontinuation is a constraint, but also a moment to harden the supply chain. With HVC HVRGXP you gain not only the same footprint but also:

• Stable supply, easing last-time-buy anxiety
• Tighter tolerance options (e.g. F = ±1% and beyond)
• Custom resistance without being limited to legacy tables
• Stronger pulse performance from an optimized thick-film stack

5. HVC Ordering Code Structure

HVR-[Series]-[Size]-[Resistance]-[Tolerance]-[TCR]-[Voltage]

Example: RK92-11HD1006F → HVR-GXP7.26-10M-F-200-2K

6. KOA RK92 series replacement cross-reference table

The table below lists common examples; contact HVC for complete part numbers, datasheets, quotations, and samples.

Note: More models are available; contact HVC for a full cross-reference list.

KOA RK92 series EOL part number reference (excerpt)

Typical RK92 part numbers are listed below (about 100 for planning reference); please verify against your company BOM.

In the face of discontinuation, HVC is a reliable second source and long-term path.

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Copyright notice: © 2026 HVC Capacitor. All rights reserved. Reproduction or commercial use is prohibited without permission. KOA and RK92 are trademarks of their respective owners; this document is for technical compatibility and replacement selection only.
Disclaimer: Technical parameters are for reference only; confirm against the latest datasheet and your purchase order.