The 10D431K is a 10mm radial-lead metal-oxide varistor (MOV) with a rated operating voltage of 275 VAC (or 350 VDC) and a nominal varistor voltage of 430 V. It is widely used for surge suppression, provided that its rated voltage and surge-handling capabilities align with the requirements of the circuit.
However, no single varistor is suitable for every design. The correct choice always depends on the actual steady-state operating voltage, the expected transient events, and the maximum voltage tolerance of the downstream components you intend to protect.
I. 10D431K Specifications
- Package: 10mm radial disc
- Maximum Continuous Voltage: 275 VAC / 350 VDC
- Varistor Voltage (@ 1mA): 430 V (Tolerance range: 387–473 V)
- Maximum Clamping Voltage: 710 V (tested at 25A)
- Single-pulse Surge Current (8/20 μs): 2500 A (standard version)
- Maximum Energy (10/1000 μs): 88.2 J (standard version)
- Typical Capacitance (@ 1kHz): 230 pF
- Operating Temperature: −40°C to +125°C
The 10D431KJ is a high-surge version, featuring a peak surge current of up to 3500 A and a maximum energy rating of 88.2 J. Please refer to the official datasheet for further details if needed.
10D431KJ datasheet: https://en.semiware.com/varistors/10d431kj/
II. Understanding the 430 V and 710 V Ratings of the 10D431K
These two specifications are frequently confused; such misunderstandings can lead to field failures.
430 V Varistor Voltage: This is the voltage measured across the MOV at a test current of 1 mA; with a tolerance of ±10%, the range is 387 V to 473 V.
This is merely a reference characteristic used for classification and does not represent a voltage that can be continuously applied to the device. Furthermore, it does not imply that the MOV will reliably clamp surge currents at 430 V.
710 V Maximum Clamping Voltage: 710 V is the peak voltage measured across the varistor during a specified clamping test at a current of 25 A.
Clamping voltage varies depending on the amplitude and waveform of the surge current. When designing protection circuits, the voltage withstand ratings of integrated circuits (ICs) and capacitors must be taken into account.
III. Typical Applications for 10D431K
- AC input surge suppression for switching power supplies
- Power input protection for washing machines and other household appliances
- Transient voltage protection for DC-DC modules (provided the voltage limits are compatible)
- General electronic equipment exposed to switching noise and low-to-medium energy line surges
IV. 10D431K vs. 10D471K
Both devices utilize the same 10 mm disc package, but their voltage ratings are designed for different power grid conditions:
- 10D431K: Rated continuous voltage of 275 VAC / 350 VDC; varistor voltage of 430 V; clamping voltage of 710 V
- 10D471K: Rated continuous voltage of 300 VAC / 385 VDC; varistor voltage of 470 V; clamping voltage of 775 V
The 10D471K can withstand a higher steady-state mains voltage, but it also features a higher clamping voltage. When selecting a component, consider your normal operating voltage range, the surge environment, and the stress limits of your other components.
V. Design Evaluation Points
- Ensure that the steady-state AC/DC voltage in the circuit never exceeds the maximum continuous operating voltage rating of the metal-oxide varistor (MOV).
- Define the expected surge waveform, peak current, and energy parameters.
- Verify that the clamping voltage remains within a safe range, ensuring no damage occurs to downstream semiconductor components.
- Optimize PCB layout, fuse selection, and thermal margin design to ensure a long service life for the product.
- Confirm that the selected components comply with the surge immunity standards and safety certification requirements applicable to the end product.
VI. Datasheets and Technical Support
For further product information, please visit our 10D431K product page, where you can download the complete MOV-10D series datasheet and view detailed dimensional specifications.
10D431K datasheet: https://en.semiware.com/varistors/10d431kj/
To request samples, inquire about volume pricing, or seek technical consultation regarding your surge protection design, please get in touch with our engineering team via our contact page.
