TVS - Varistors, MOVs

Image Part Number Description / PDF Quantity Rfq
VG121065P131DP

VG121065P131DP

Elco (AVX)

VARISTOR 47V 350A 1210

735

VCAS120642K900DP

VCAS120642K900DP

Elco (AVX)

VARISTOR 56V 200A 1206

1513

VC040205X150WP

VC040205X150WP

Elco (AVX)

VARISTOR 8.5V 20A 0402

208672

VC080514C300DP

VC080514C300DP

Elco (AVX)

VARISTOR 18.5V 120A 0805

13753

VC121026H560DP

VC121026H560DP

Elco (AVX)

VARISTOR 34.5V 300A 1210

6906

VC120603A100RP

VC120603A100RP

Elco (AVX)

VARISTOR 5V 40A 1206

0

VCAS04AP181R5DATWA

VCAS04AP181R5DATWA

Elco (AVX)

VARISTOR 180V 1A 0402

9250

VC120631M650DP

VC120631M650DP

Elco (AVX)

VARISTOR 39V 200A 1206

1405

USB0001DP

USB0001DP

Elco (AVX)

VARISTOR 120V 4A 0603

10850

VLAS121016J350DP

VLAS121016J350DP

Elco (AVX)

LOW CLAMP AUTOMOTIVE SERIES VAR

1000

VC06AG183R0YAT1A

VC06AG183R0YAT1A

Elco (AVX)

VARISTOR 0603

97

VC120605D150DP

VC120605D150DP

Elco (AVX)

VARISTOR 8.5V 150A 1206

6579

VCAS060318A400DP

VCAS060318A400DP

Elco (AVX)

VARISTOR 25.5V 30A 0603

9643000

VC120614A300DP

VC120614A300DP

Elco (AVX)

VARISTOR 18.5V 40A 1206

245

VCAS121030H620DP

VCAS121030H620DP

Elco (AVX)

VARISTOR 41V 280A 1210

5356

VGAS121048H101DP

VGAS121048H101DP

Elco (AVX)

VARISTOR 62V 250A 1210

0

VG181218P440DP

VG181218P440DP

Elco (AVX)

VARISTOR 27.5V 800A 1812

0

CAN0001DP

CAN0001DP

Elco (AVX)

VARISTOR 0603

500

VGAS121060J121DP

VGAS121060J121DP

Elco (AVX)

VARISTOR 76V 250A 1210

342

VCAS080505C150DP

VCAS080505C150DP

Elco (AVX)

VARISTOR 8.5V 120A 0805

178

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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