TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
B72214S1300K102 TDK EPCOS	VARISTOR 47V 1KA DISC 14MM	210
B72210U2351K501 TDK EPCOS	10MM, 350VAC, 10% ADVANCED, 125D	0
B72205S0141K111 TDK EPCOS	VARISTOR 220V 400A DISC 5MM	4500
B72220S0750K101 TDK EPCOS	VARISTOR 120V 6.5KA DISC 20MM	293
B72220S0301K101 TDK EPCOS	VARISTOR 470V 8KA DISC 20MM	14171
B72220S0110K101 TDK EPCOS	VARISTOR 18V 2KA DISC 20MM	0
B72232B0231K001 TDK EPCOS	VARISTOR 360V 25KA ENCASED DISC	3
B72660M0301K072 TDK EPCOS	VARISTOR 470V 1.2KA 2SMD JLEAD	3448
B72520T0600K062 TDK EPCOS	VARISTOR 100V 100A 1206	56809
B72232B0681K001 TDK EPCOS	VARISTOR 1.1KV 25KA ENCASED DISC	142
B72500E0140K060 TDK EPCOS	VARISTOR 22V 30A 0603	15975
B72220S1250K102 TDK EPCOS	VARISTOR 39V 2KA DISC 20MM	781
B72207S0441K311 TDK EPCOS	VARISTOR 715V 1.2KA DISC 7MM	9610
B72210S0110K101 TDK EPCOS	VARISTOR 18V 500A DISC 10MM	1521
B72540G0300K062 TDK EPCOS	CT2220K30G_G	0
B72210S0151K551 TDK EPCOS	VARISTOR 240V 2.5KA DISC 10MM	2924
B72220T2381K101 TDK EPCOS	VARISTOR 620V 10KA RADIAL BOX	0
B72225S4131K101 TDK EPCOS	VARISTOR 205V 20KA DISC 27.5MM	1958
B72500T0250K060 TDK EPCOS	VARISTOR 39V 30A 0603	64785
B72205S2271K311 TDK EPCOS	VARISTOR 430V 800A DISC 5MM	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