TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
B72220T2231K105 TDK EPCOS	VARISTOR 360V 10KA RADIAL BOX	358
B72225S4251K101 TDK EPCOS	VARISTOR 390V 20KA DISC 27.5MM	0
B72205S0140K211 TDK EPCOS	VARISTOR 22V 100A DISC 5MM	4500
B72210S0301K151 TDK EPCOS	VARISTOR 470V 2.5KA DISC 10MM	2641
B72530G0250K062 TDK EPCOS	CT1210K25G_G	0
B72280B0131K001 TDK EPCOS	VARISTOR 205V 100KA ENCASED DISC	0
B72240B0441K001 TDK EPCOS	VARISTOR 715V 40KA ENCASED DISC	9
B72214U2301K502 TDK EPCOS	14MM, 300VAC, 10% ADVANCED, 125D	0
B72520G0400K062 TDK EPCOS	CT1206K40G_G	0
B72582V0300K062 TDK EPCOS	VARISTOR 47V 800A 1812	7388
B72210S0271K151 TDK EPCOS	VARISTOR 430V 2.5KA DISC 10MM	2172
B72250L0441K100 TDK EPCOS	VARISTOR 715V 75KA DISC 57MM	0
B72500G0250K060 TDK EPCOS	CT0603K25G_G	0
B72220Q0151K101 TDK EPCOS	VARISTOR 240V 15KA RADIAL	0
B72650M0141K093 TDK EPCOS	VARISTOR 220V 400A 1210	1470
B72500E1140S260 TDK EPCOS	VARISTOR 24.5V 30A 0603	8045
B72214S0421K201 TDK EPCOS	VARISTOR 680V 4.5KA DISC 14MM	0
B72214P2621K101 TDK EPCOS	VARISTOR 1KV 6KA DISC 14MM	193
B72205S0111K111 TDK EPCOS	VARISTOR 180V 400A DISC 5MM	0
B72220S0250K151 TDK EPCOS	VARISTOR 39V 2KA DISC 20MM	416

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

Type	Functional Characteristics	Application Examples
TVS Diodes	Unidirectional/bidirectional clamping, sub-nanosecond response time, low leakage current	Communication interfaces (USB, HDMI), microcontrollers, power supplies
Zinc Oxide Varistors	High energy absorption, voltage-dependent resistance, aging characteristics	Power line protection, industrial motor drives, surge protection strips
MOVs	Specialized varistors with metal oxide ceramics, optimized for AC/DC applications	Appliances, 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

Parameter	Description	Importance
Clamping Voltage (V_CLAMP)	Voltage level during surge conduction	Determines protection level for downstream components
Response Time	Time to transition from blocking to clamping mode	TVS: 0.5-10 ns; MOVs: 10-50 ns
Energy Absorption (W_ADM)	Maximum surge energy handling capability	Measured in joules (J), critical for industrial applications
Leakage Current	Off-state current at rated voltage	Impacts 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

Manufacturer	Representative Product	Key Specifications
Littelfuse	SM712-02	12A, 13.3V clamping, bidirectional TVS for RS-485
Bourns	V14450A	14mm MOV, 450VAC, 210J energy rating
STMicroelectronics	TV05C060	0.5W, 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