TVS - Varistors, MOVs

Image Part Number Description / PDF Quantity Rfq
MG052S05A150TP

MG052S05A150TP

Elco (AVX)

MULTIGUARD

0

VA100018A400RL

VA100018A400RL

Elco (AVX)

VARISTOR LEADED

0

VA10LC18A500RL

VA10LC18A500RL

Elco (AVX)

VARISTOR LEADED

0

VC121016J390DP

VC121016J390DP

Elco (AVX)

TRANSGUARD

0

VC120614D300TP

VC120614D300TP

Elco (AVX)

TRANSGUARD

0

VCAS120618E380DP

VCAS120618E380DP

Elco (AVX)

TRANSGUARD

0

VC120648D101TP

VC120648D101TP

Elco (AVX)

TRANSGUARD

0

VC121016J390RP

VC121016J390RP

Elco (AVX)

TRANSGUARD

0

VA100018D400TL

VA100018D400TL

Elco (AVX)

VARISTOR LEADED

0

VCUG120100H1DP

VCUG120100H1DP

Elco (AVX)

TRANSGUARD

0

VCAS060305A150RP

VCAS060305A150RP

Elco (AVX)

TRANSGUARD

4000

VTA7060331A670RP

VTA7060331A670RP

Elco (AVX)

TVS, HI-TEMP. 175 C, 0603 EIA, 3

0

VCUG120075L1DP

VCUG120075L1DP

Elco (AVX)

TRANSGUARD

0

VA100003D100RL

VA100003D100RL

Elco (AVX)

VARISTOR LEADED

0

VCUG120150H1TP

VCUG120150H1TP

Elco (AVX)

TRANSGUARD

0

CAN0002DP

CAN0002DP

Elco (AVX)

MULTIGUARD

0

VCAS120626F540RP

VCAS120626F540RP

Elco (AVX)

TRANSGUARD

0

VCAS120648D101RP

VCAS120648D101RP

Elco (AVX)

TRANSGUARD

0

VC120618D400TP

VC120618D400TP

Elco (AVX)

TRANSGUARD

0

MAV0020TP

MAV0020TP

Elco (AVX)

MULTIGUARD

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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