TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
B72214S2271K301 TDK EPCOS	VARISTOR 430V 6KA DISC 14MM	0
B72225T4151K101 TDK EPCOS	VARISTOR 240V 20KA RADIAL BOX	0
B72232B0131K001 TDK EPCOS	VARISTOR 205V 25KA ENCASED DISC	233
B72280B0271K001 TDK EPCOS	VARISTOR 430V 100KA ENCASED DISC	7
B72540E0250K062 TDK EPCOS	VARISTOR 39V 1.2KA 2220	2242
B72220T2301K105 TDK EPCOS	VARISTOR 470V 3KA RADIAL BOX 3LD	0
B72540T0400K062 TDK EPCOS	VARISTOR 68V 1KA 2220	2
B72230M0511M401 TDK EPCOS	30MM, 510V, 25KA, THERMO FUSE TY	400
B72260B0231K001 TDK EPCOS	VARISTOR 360V 70KA ENCASED DISC	29
B72520E0170K062 TDK EPCOS	VARISTOR 27V 200A 1206	10495
B72520T1140S272 TDK EPCOS	VARISTOR 22V 200A 1206	0
B72220S0321K151 TDK EPCOS	VARISTOR 510V 8KA DISC 20MM	0
B72214S0321K101 TDK EPCOS	VARISTOR 510V 4.5KA DISC 14MM	57580
B72220S3321K101 TDK EPCOS	VARISTOR 510V 12KA DISC 20MM	788
B72210S0250K101 TDK EPCOS	VARISTOR 39V 500A DISC 10MM	4806
B72220S0551K101 TDK EPCOS	VARISTOR 910V 6.5KA DISC 20MM	451
B72220S0141K101 TDK EPCOS	VARISTOR 220V 8KA DISC 20MM	1421
B72540E0400K062 TDK EPCOS	VARISTOR 68V 1KA 2220	4111
B72214S0140K101 TDK EPCOS	VARISTOR 22V 1KA DISC 14MM	2565
B72241L0271K100 TDK EPCOS	VARISTOR 430V 50KA ENCASED DISC	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

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