TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
B72232B0751K001 TDK EPCOS	VARISTOR 1.2KV 25KA ENCASED DISC	538
B72214S1140K552 TDK EPCOS	VARISTOR 22V 1KA DISC 14MM	0
B72220T2171K105 TDK EPCOS	VARISTOR 270V 10KA RADIAL BOX	0
B72540E0140K062 TDK EPCOS	VARISTOR 22V 1.2KA 2220	1962
B72210S0321K101 TDK EPCOS	VARISTOR 510V 2.5KA DISC 10MM	14704
B72207S1140K201 TDK EPCOS	VARISTOR 22V 250A DISC 7MM	5183
B72214S0511K301 TDK EPCOS	VARISTOR 820V 4.5KA DISC 14MM	0
B72220T2301K101 TDK EPCOS	VARISTOR 470V 10KA RADIAL BOX	0
B72220T2151K105 TDK EPCOS	VARISTOR 240V 10KA RADIAL BOX	1500
B72207S0350K111 TDK EPCOS	VARISTOR 56V 250A DISC 7MM	8480
B72210S0300K101 TDK EPCOS	VARISTOR 47V 500A DISC 10MM	1655
B72650M0950K072 TDK EPCOS	VARISTOR 150V 400A 2SMD JLEAD	1680
B72214S0301K151 TDK EPCOS	VARISTOR 470V 4.5KA DISC 14MM	3737
B72210S2301K111 TDK EPCOS	VARISTOR 470V 3.5KA DISC 10MM	0
B72207S0400K111 TDK EPCOS	VARISTOR 68V 250A DISC 7MM	4012
B72220T2151K101 TDK EPCOS	VARISTOR 240V 10KA RADIAL BOX	350
B72500G0140K060 TDK EPCOS	CT0603K14G_G	0
B72540E0200K062 TDK EPCOS	VARISTOR 33V 1.2KA 2220	804
B72205U2271K501 TDK EPCOS	VARISTOR 430V 800A DISC 5MM	822
B72214W2381K101 TDK EPCOS	VARISTOR 620V 6KA DISC 17MM	379

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