TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
B72230M0151M401 TDK EPCOS	30MM, 150V, 25KA, THERMO FUSE TY	800
B72214S2321K101 TDK EPCOS	VARISTOR 510V 6KA DISC 14MM	3020
B72220S2211K101 TDK EPCOS	VARISTOR 330V 10KA DISC 20MM	6
B72225S4271K101 TDK EPCOS	VARISTOR 430V 20KA DISC 27.5MM	1012
B72210S0301K551 TDK EPCOS	VARISTOR 470V 2.5KA DISC 10MM	1634
B72510T0040M062 TDK EPCOS	VARISTOR 8V 100A 0805	86438
B72214S0250K151 TDK EPCOS	VARISTOR 39V 1KA DISC 14MM	1101
B72214S0681K101 TDK EPCOS	VARISTOR 1.1KV 4.5KA DISC 14MM	4307
B72207S0350K101 TDK EPCOS	VARISTOR 56V 250A DISC 7MM	69480
B72214S0102K101 TDK EPCOS	VARISTOR 1.8KV 4.5KA DISC 14MM	2695
B72280B0321K001 TDK EPCOS	VARISTOR 510V 100KA ENCASED DISC	4
B72210S0421K131 TDK EPCOS	VARISTOR 680V 2.5KA DISC 10MM	0
B72590D0200H060 TDK EPCOS	VARISTOR 0402	15827
B72207S0300K111 TDK EPCOS	VARISTOR 47V 250A DISC 7MM	153
B72207S0171K111 TDK EPCOS	VARISTOR 270V 1.2KA DISC 7MM	5910
B72220S0170K101 TDK EPCOS	VARISTOR 27V 2KA DISC 20MM	5584
B72205S0170K311 TDK EPCOS	VARISTOR 27V 100A DISC 5MM	0
B72250L0271K102 TDK EPCOS	VARISTOR 430V 75KA DISC 57MM	0
B72205S0131K211 TDK EPCOS	VARISTOR 205V 400A DISC 5MM	0
B72590T7050S160 TDK EPCOS	VARISTOR 255V 0402	10400

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