The NVD10UCD470 is a high-performance Metal Oxide Varistor (MOV) disc type designed by KOA Speer Electronics for superior circuit protection. Engineered to safeguard sensitive electronics, it excels at suppressing transient voltages and managing high surge currents with its excellent V-I characteristics that remain consistent across both polarities.
Despite its robust performance and flame-retardant construction, it is critical for engineers and procurement teams to note that this series has reached its End of Life (EOL) status. The last official date to purchase this component was December 25, 2020, making it essential for users to evaluate existing inventories or identify modern alternatives for future maintenance and design needs
Physical Design and Construction
The NVD10UCD470 is engineered with a focus on durability and safety, adhering to strict industrial standards for construction. Its physical architecture is designed to provide maximum protection within a compact footprint.
Dimensions and Footprint
The NVD10 series features a disc-type construction with a maximum diameter of 12.0 mm. This 10mm nominal size allows for high energy absorption while maintaining a space-efficient profile on printed circuit boards (PCBs). The lead spacing is standardized at 7.5 mm, which facilitates easy integration into most power circuit layouts.
| Feature | Specification |
|---|
| Component Type | Metal Oxide Varistor (MOV) Disc |
| Disc Diameter (D max.) | 12.0 mm |
| Body Thickness (t max.) | Varies by voltage (approx. 4.3mm to 14.4mm) |
| Lead Spacing (F) | 7.5 mm (+/- 1.0 mm) |
| Lead Wire Diameter (d) | 0.8 mm |
Safety Coating and Material Standards
Safety is a paramount consideration in the construction of the NVD series. The device is encased in a flame retardant coating that meets the UL94V0 standard. This rating ensures that the coating is self-extinguishing and will not contribute to the spread of fire in the event of a catastrophic electrical failure or extreme overheating.
Lead-Free and Environmental Compliance
KOA Speer has designed this component to align with global environmental regulations. The NVD10UCD470 features lead-free terminations and is fully compliant with EU RoHS requirements. This compliance ensures that the product is free from hazardous substances like lead, mercury, and cadmium, making it suitable for modern, eco-friendly manufacturing processes.
Decoding the Technical Specifications
To effectively implement the NVD10UCD470 in a circuit protection strategy, one must analyze its data-driven performance metrics. These specifications define the boundary between normal operation and the protective state.
Voltage Ratings and Thresholds
The voltage ratings determine when the varistor transitions from a high-resistance insulator to a low-resistance conductor to shunt excess energy.
Varistor Voltage: The nominal rating is 470V, measured at a current of 1mA. The actual manufacturing tolerance allows for a range between 437V and 517V.
Maximum Allowable Voltage: This is the maximum continuous voltage the device can withstand without triggering. For the NVD10UCD470, the limits are 300V AC (rms) and 385V DC.
Surge Handling and Energy Dissipation
Surge ratings define the "muscle" of the varistor—its ability to absorb and dissipate massive electrical hits without being destroyed.
Peak Current: The device is rated to handle a maximum peak current of 2500 Amps for two pulses (8/20 microseconds).
Energy Absorption: It is capable of absorbing up to 30.0 Joules of energy during a 2ms pulse, providing significant thermal headroom for transient events.
Clamping Performance
The clamping voltage is perhaps the most critical metric for protecting downstream components, as it represents the maximum voltage that will be "let through" to the rest of your circuit during a surge.
Specification Summary Table
| Parameter | Value |
|---|
| Varistor Voltage (at 1mA) | 470V (437V to 517V) |
| Max Allowable AC Voltage | 300V rms |
| Max Allowable DC Voltage | 385V |
| Max Peak Current (2 pulses) | 2500A |
| Max Energy (2ms) | 30.0 Joules |
| Max Clamping Voltage (at 25A) | 775V |
Advanced Features and Performance Characteristics
Beyond the raw numbers, the NVD10UCD470 incorporates specific design features that ensure long term stability and versatility in demanding environments.
Bidirectional Protection for AC Applications
One of the standout functional features of the NVD10UCD470 is its symmetrical protection capability. The Voltage Current characteristics are identical in both positive and negative polarities. This bidirectional nature makes it an ideal component for AC power line applications, as it provides consistent clamping performance regardless of the direction of the transient surge.=
Rigorous Reliability Testing
To guarantee performance in industrial and outdoor settings, the NVD series undergoes extensive environmental stress testing. These tests ensure that the varistor can withstand prolonged exposure to heat, moisture, and electrical stress without significant degradation.
High Temperature Life with Bias The component is tested for 1000 hours at 85 degrees Celsius while under maximum allowable circuit voltage bias. This ensures the device maintains its protective properties even after years of operation in hot enclosures.
High Temperature and High Humidity Life The NVD10UCD470 is subjected to 80 degrees Celsius and 95 percent relative humidity for 1000 hours. This test confirms the integrity of the flame retardant coating and its ability to prevent moisture induced failure.
Resistance to Solder Heat During the manufacturing process, the device can withstand 260 degrees Celsius for 10 seconds, ensuring that the internal metal oxide structure is not damaged during PCB assembly.
Solderability Standards To ensure high quality PCB manufacturing, the terminations are required to achieve a minimum of 95 percent solder coverage. This minimizes the risk of cold solder joints or connectivity issues in the field.
Performance Reliability Summary Table
| Test Parameter | Condition | Requirement |
|---|
| High Temperature Life | 85C, 1000 Hours, DC or AC Bias | Change within 10 percent |
| Humidity Resistance | 80C, 95 percent RH, 1000 Hours | Change within 5 percent |
| Low Temperature Storage | Negative 40C, 1000 Hours | Change within 5 percent |
| Solderability | 230C to 250C (Pb free) | 95 percent coverage |
Application and Circuit Design Insights
Integrating the NVD10UCD470 into a system requires an understanding of both safety certifications and practical implementation strategies to ensure maximum reliability.
Compliance with Industry Standards
Safety is a core requirement for components handling high-voltage transients. The NVD10UCD470 is officially recognized under the UL1449 standard (File Number E328032). This certification ensures that the varistor meets rigorous safety criteria for Surge Protective Devices, providing peace of mind for engineers designing products for global markets.
Typical Usage: The 470V Sweet Spot
In circuit design, the 470V rating is often considered a "sweet spot" for applications involving 220V or 230V AC power lines. Here is why this specific voltage is frequently selected:
Voltage Headroom: With a maximum allowable AC voltage of 300V rms, the NVD10UCD470 comfortably handles standard 230V mains power even during minor grid fluctuations.
Effective Protection: The nominal 470V breakdown voltage is high enough to avoid nuisance tripping during normal operation, yet low enough to clamp dangerous surges before they exceed the dielectric insulation limits of downstream components.
Versatile Integration: This balance makes it a go-to choice for switching power supplies, industrial control boards, and smart meters where reliable overvoltage protection is non-negotiable.
Visualizing Performance with V-I Curves
Understanding how the NVD10UCD470 behaves during a surge is best achieved by analyzing the Voltage-Current (V-I) Curves found in the technical documentation.
The curve illustrates three distinct regions of operation:
Leakage Region: At normal operating voltages (below the varistor voltage), the device draws extremely low current, typically in the microampere range.
Transition/Breakdown Region: As the voltage approaches the 437V to 517V range, the device resistance drops sharply, and current begins to flow through the varistor.
Clamping Region: During a high-current surge, the varistor enters the clamping state, maintaining a relatively stable voltage (up to 775V at 25A) to protect the rest of the circuit from the full force of the transient.
Ordering and Identification Guide
Understanding the nomenclature of the NVD series is essential for ensuring you select the correct component for your specific design requirements. Each character in the part number represents a critical physical or electrical characteristic.
Part Number Breakdown
The part number NV D 10 U C D 470 can be decoded as follows based on the manufacturer's ordering information:
NV: This designates the product type as a Varistor.
D: Indicates the Style is a Disc type.
10: Refers to the Diameter of the disc, which is 10mm.
U: Represents the specific U Series of the product.
C: Denotes the Termination Material, specifically Sn-Cu.
D: Refers to the Inner Connect Solder Material, which is SnAgCu.
470: Specifies the Varistor Voltage, where 470 represents 470V.
Packaging and Assembly Options
For high-volume manufacturing, the NVD10UCD470 offers various packaging styles to support automated assembly lines:
Ammo Packaging: Identified by the code A, this is a common bulk-packaging format for automated insertion.
Lead Taping Styles: Depending on your PCB layout, you can choose between different taping configurations:
MT: 5mm straight taping.
MHT: 5mm inside kink taping.
MJT: 5mm or 7.5mm outside kink taping, depending on the specific model requirements.
Availability at Nantian Electronics
While the NVD series reached its official End of Life (EOL) with the manufacturer in late 2020, we understand that many critical systems still rely on this exact specification for maintenance and continued production.
Nantian Electronics is proud to announce that we currently have the NVD10UCD470 in stock and ready for immediate shipment. As a premier supplier of electronic components, we specialize in sourcing high-quality, hard-to-find, and EOL parts to keep your production lines running smoothly.
Our services include:
Rigorous Quality Assurance: Every batch undergoes strict inspection to ensure authentic performance.
Fast Global Shipping: We minimize your downtime with efficient logistics.
Technical Support: Our team can help you verify specifications or find viable alternatives for your legacy designs.
Don't let EOL status disrupt your project. Contact Nantian Electronics today for a quote on our NVD10UCD470 inventory and experience our commitment to excellence in component distribution.
Conclusion: Reliability in Protection
The NVD10UCD470 is more than just a simple component; it is a critical insurance policy for your electrical systems. By combining a 10mm compact form factor with a high 470V varistor voltage and 2500A peak current capacity, it provides a robust barrier against the unpredictable nature of power surges. Its bidirectional symmetry and UL1449 safety certification make it a trusted choice for 230V AC line protection across industrial and consumer applications.
While the official manufacturer production has ceased, the demand for this specific level of protection remains high. Maintaining the integrity of legacy systems and specialized power boards requires access to authentic, high-quality parts.
At Nantian Electronics, we bridge the gap between supply and demand. By maintaining a ready stock of the NVD10UCD470, we ensure that your operations never have to stall due to component obsolescence. We invite you to partner with us for your procurement needs, benefiting from our commitment to quality, speed, and technical expertise. Secure your circuits today by reaching out to our team for the reliable protection your hardware deserves.
Frequently Asked Questions (FAQ)
What does the "470" in NVD10UCD470 represent?
In the NVD series nomenclature, "470" signifies the Varistor Voltage. Specifically, it indicates a nominal voltage of 470V when a 1mA current is applied. In practical operation, this voltage typically ranges between 437V and 517V.
Is this varistor suitable for 220V or 230V AC power lines?
Absolutely. The NVD10UCD470 has a maximum allowable AC voltage of 300V rms. This provides an ideal safety margin for standard 220V/230V mains power, ensuring the device remains inactive during normal fluctuations while responding instantly to dangerous overvoltage spikes.
What is the maximum surge current this device can handle?
According to the datasheet, this model is rated for a peak surge current of up to 2500 Amps (for an 8/20 microsecond pulse). This high-current tolerance makes it highly effective against industrial-grade transients and inductive switching noise.
Since this series is officially End of Life (EOL), why is it still available at Nantian Electronics?
While the original manufacturer (KOA Speer) ceased production in late 2020, Nantian Electronics specializes in supporting legacy systems and long-term production cycles. We maintain an active inventory of the NVD10UCD470 to ensure our clients can maintain their equipment without the need for costly redesigns. Every unit we supply undergoes rigorous quality verification.
What are the benefits of the bidirectional protection feature?
Bidirectional protection means that the Voltage-Current (V-I) characteristics are identical for both positive and negative polarities. This is critical for AC applications, as the varistor provides consistent clamping performance regardless of whether the surge occurs on the positive or negative half-cycle of the sine wave.
Does the NVD10UCD470 comply with international safety standards?
Yes. It is recognized under UL1449 (File No. E328032), which is the gold standard for Surge Protective Devices. Additionally, it features a UL94V0 flame-retardant coating and is fully compliant with EU RoHS environmental requirements.
What is the recommended placement for this varistor in a circuit?
For optimal safety, it is standard practice to place the NVD10UCD470 downstream of a fuse. In the event of a sustained overvoltage that causes the varistor to conduct continuously, the resulting high current will blow the fuse, safely disconnecting the circuit and preventing potential fire hazards.
