TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
B72220S1300K102 TDK EPCOS	VARISTOR 47V 2KA DISC 20MM	899
B72207S0131K111 TDK EPCOS	VARISTOR 205V 1.2KA DISC 7MM	2295
B72590D0150A060 TDK EPCOS	VARISTOR 20V 10A 0402	33666
B72214Q0131K101 TDK EPCOS	VARISTOR 205V 8KA RADIAL	0
B72210S0171K551 TDK EPCOS	VARISTOR 270V 2.5KA DISC 10MM	634
B72530G1250K062 TDK EPCOS	CT1210K25AUTOG_G	0
B72520G1200K062 TDK EPCOS	VARISTOR MLV 1206	0
B72214S0271K531 TDK EPCOS	VARISTOR 430V 4.5KA DISC 14MM	1876
B72225M0151M301 TDK EPCOS	25MM, 150V, 20KA, THERMO FUSE TY	0
B72220P3171K101 TDK EPCOS	VARISTOR 270V 12KA DISC 20MM	1251
B72214S0111K551 TDK EPCOS	VARISTOR 180V 4.5KA DISC 14MM	0
B72650M0251K093 TDK EPCOS	VARISTOR 390V 400A 2SMD JLEAD	0
B72205S0381K101 TDK EPCOS	VARISTOR 620V 400A DISC 5MM	4630
B72520T0140K062 TDK EPCOS	VARISTOR 22V 200A 1206	6
B72714D0160H060 TDK EPCOS	VARISTOR 22V 0508	1301
B72250L0421K102 TDK EPCOS	VARISTOR 680V 75KA DISC 57MM	0
B72225T4251K101 TDK EPCOS	VARISTOR 390V 20KA RADIAL BOX	0
B72214Q0171K101 TDK EPCOS	VARISTOR 270V 8KA RADIAL	2999
B72210S0301K101 TDK EPCOS	VARISTOR 470V 2.5KA DISC 10MM	11269
B72500T0060M060 TDK EPCOS	VARISTOR 11V 30A 0603	16880

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