TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
B72220S0271K101 TDK EPCOS	VARISTOR 430V 8KA DISC 20MM	19215
B72214X2301K501 TDK EPCOS	14MM, 300VAC, 10% ADVANCED AUTO,	0
B72250L0131K100 TDK EPCOS	VARISTOR 205V 75KA DISC 57MM	0
B72540V1140S262 TDK EPCOS	VARISTOR 22V 1.2KA 2220	50
B72210S0621K351 TDK EPCOS	VARISTOR 1KV 2.5KA DISC 10MM	2972
B72650M1170K093 TDK EPCOS	VARISTOR 27V 100A 3225	0
B72530G1200K062 TDK EPCOS	CT1210K20AUTOG_G	0
B72210S0461K351 TDK EPCOS	VARISTOR 750V 2.5KA DISC 10MM	5950
B72580E0350K062 TDK EPCOS	VARISTOR 56V 500A 1812	3609
B72520T0040M062 TDK EPCOS	VARISTOR 8V 150A 1206	571
B72220Q0381K101 TDK EPCOS	VARISTOR 620V 15KA DISC 20MM	636
B72232B0271K001 TDK EPCOS	VARISTOR 430V 25KA ENCASED DISC	100
B72500T7050S160 TDK EPCOS	VARISTOR 255V 0603	536
B72650M1170K072 TDK EPCOS	VARISTOR 27V 100A 2SMD JLEAD	1970
B72650M0350K072 TDK EPCOS	VARISTOR 56V 100A 2SMD JLEAD	5395
B72210S0301K331 TDK EPCOS	VARISTOR 470V 2.5KA DISC 10MM	0
B72542V0300K062 TDK EPCOS	VARISTOR 47V 1.2KA 2220	672
B72580V0300K062 TDK EPCOS	VARISTOR 47V 800A 1812	0
B72214S0350K531 TDK EPCOS	VARISTOR 56V 1KA DISC 14MM	0
B72660M0131K072 TDK EPCOS	VARISTOR 205V 1.2KA 4032	1321

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