TVS - Varistors, MOVs

Image Part Number Description / PDF Quantity Rfq
82556250

82556250

Würth Elektronik Midcom

SMT VARISTOR POWER WE-VS 0603; 2

98

820522711

820522711

Würth Elektronik Midcom

DISK VARISTOR STANDARD 20MM; 275

0

820527501

820527501

Würth Elektronik Midcom

DISK VARISTOR STANDARD 20MM; 75V

0

82550080

82550080

Würth Elektronik Midcom

SMT VARISTOR POWER WE-VS 0805; 8

0

820524611

820524611

Würth Elektronik Midcom

DISK VARISTOR STANDARD 20MM; 460

181

82551500

82551500

Würth Elektronik Midcom

SMT VARISTOR POWER WE-VS 1206; 5

3950

820522511

820522511

Würth Elektronik Midcom

DISK VARISTOR STANDARD 20MM; 250

0

820521311

820521311

Würth Elektronik Midcom

DISK VARISTOR STANDARD 20MM; 130

0

82557060

82557060

Würth Elektronik Midcom

SMT VARISTOR POWER WE-VS 0402; 6

10000

82531140

82531140

Würth Elektronik Midcom

SMT VARISTOR POWER WE-VS 1206; 1

0

82551250

82551250

Würth Elektronik Midcom

SMT VARISTOR POWER WE-VS 1206; 2

0

82551170

82551170

Würth Elektronik Midcom

SMT VARISTOR POWER WE-VS 1206; 1

0

82535300

82535300

Würth Elektronik Midcom

VARISTOR 47V 800A 1812

0

82553400

82553400

Würth Elektronik Midcom

VARISTOR 68V 250A 1210

0

82542350

82542350

Würth Elektronik Midcom

VARISTOR 56V 1.2KA 2220

0

82553040

82553040

Würth Elektronik Midcom

VARISTOR 8V 250A 1210

0

82555140

82555140

Würth Elektronik Midcom

VARISTOR 24V 500A 1812

0

82542140

82542140

Würth Elektronik Midcom

VARISTOR 24V 1.2KA 2220

0

82535250

82535250

Würth Elektronik Midcom

VARISTOR 39V 800A 1812

0

82532300

82532300

Würth Elektronik Midcom

VARISTOR 47V 1.2KA 2220

0

TVS - Varistors, MOVs

1. Overview

Transient Voltage Suppressors (TVS), Varistors, and Metal Oxide Varistors (MOVs) are critical components for protecting electronic circuits from voltage spikes and electrostatic discharge (ESD). These devices clamp excessive voltage to safe levels, preventing damage to sensitive components. TVS diodes are semiconductor-based solutions with fast response times, while Varistors (including MOVs) use nonlinear resistive materials to absorb energy. Their importance spans industries like telecommunications, automotive, and consumer electronics, ensuring reliability in environments exposed to electrical surges.

2. Main Types and Functional Classification

TypeFunctional CharacteristicsApplication Examples
TVS DiodesUnidirectional/bidirectional clamping, sub-nanosecond response time, low leakage currentCommunication interfaces (USB, HDMI), microcontrollers, power supplies
Zinc Oxide VaristorsHigh energy absorption, voltage-dependent resistance, aging characteristicsPower line protection, industrial motor drives, surge protection strips
MOVsSpecialized varistors with metal oxide ceramics, optimized for AC/DC applicationsAppliances, LED lighting, renewable energy systems

3. Structure and Composition

TVS diodes employ a PN junction semiconductor structure with doping profiles optimized for breakdown characteristics. Varistors consist of polycrystalline ceramic materials (typically zinc oxide grains with additives) sandwiched between metal electrodes, encapsulated in epoxy or molded housings. MOVs use similar materials to varistors but with enhanced grain boundary engineering for improved voltage clamping. All devices incorporate termination coatings (e.g., silver, tin) for PCB mounting compatibility.

4. Key Technical Parameters

ParameterDescriptionImportance
Clamping Voltage (VCLAMP)Voltage level during surge conductionDetermines protection level for downstream components
Response TimeTime to transition from blocking to clamping modeTVS: 0.5-10 ns; MOVs: 10-50 ns
Energy Absorption (WADM)Maximum surge energy handling capabilityMeasured in joules (J), critical for industrial applications
Leakage CurrentOff-state current at rated voltageImpacts power efficiency, typically <100 A

5. Application Fields

Key industries include:

  • Consumer Electronics: Smartphone charging circuits, TV power supplies
  • Industrial Automation: PLCs, motor drives, sensor interfaces
  • Automotive: ECU protection, CAN bus interfaces, battery management systems
  • Renewable Energy: Solar inverters, wind turbine controllers

Case Study: MOVs in smart meters provide 10kA surge protection against grid transients.

6. Leading Manufacturers and Products

ManufacturerRepresentative ProductKey Specifications
LittelfuseSM712-0212A, 13.3V clamping, bidirectional TVS for RS-485
BournsV14450A14mm MOV, 450VAC, 210J energy rating
STMicroelectronicsTV05C0600.5W, 6V, ultra-small TVS for IoT devices

7. Selection Guidelines

Key considerations:

  • Operating voltage vs. clamping voltage margin
  • Surge current requirements (8/20 s waveform standard)
  • Package size constraints (SMD vs. through-hole)
  • Environmental conditions (temperature, humidity)
  • Lifespan expectations (MOVs degrade with repeated surges)

8. Industry Trends

Emerging trends include:

  • Miniaturization: Sub-0201 TVS devices for mobile applications
  • Higher energy density: MOVs with >1000J/cm absorption
  • Integration: Combined ESD and surge protection solutions
  • Automotive focus: AEC-Q qualified devices for 48V systems
  • Green manufacturing: Lead-free and RoHS-compliant materials
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