TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
B72500E0170K060 TDK EPCOS	VARISTOR 27V 30A 0603	4040
B72530G1170K062 TDK EPCOS	CT1210K17AUTOG_G	5715
B72220S0251K551 TDK EPCOS	VARISTOR 390V 8KA DISC 20MM	1674
B72220P3301K101 TDK EPCOS	VARISTOR 470V 12KA DISC 20MM	1128
B72210S0110K151 TDK EPCOS	VARISTOR 18V 500A DISC 10MM	0
B72650M0200K072 TDK EPCOS	VARISTOR 33V 100A 2SMD JLEAD	346
B72510T0060M062 TDK EPCOS	VARISTOR 11V 120A 0805	9258
B72220U2511K501 TDK EPCOS	VARISTOR 820V 10KA DISC 20MM	205
B72260B0681K001 TDK EPCOS	VARISTOR 1.1KV 70KA ENCASED DISC	17
B72530V1140S262 TDK EPCOS	VARISTOR 22V 400A 1210	2070
B72500D0160H060 TDK EPCOS	VARISTOR 65V 0603	3303
B72210P2321K101 TDK EPCOS	VARISTOR 510V 3.5KA DISC 10MM	9767
B72660M0110K072 TDK EPCOS	VARISTOR 18V 250A 2SMD JLEAD	1243
B72220P3381K101 TDK EPCOS	VARISTOR 620V 12KA DISC 20MM	3926
B72214S0131K551 TDK EPCOS	VARISTOR 205V 4.5KA DISC 14MM	2565
B72220Q0131K101 TDK EPCOS	VARISTOR 205V 15KA RADIAL	0
B72540V0250K062 TDK EPCOS	VARISTOR 39V 1.2KA 2220	2278
B72210S1140K501 TDK EPCOS	VARISTOR 22V 500A DISC 10MM	764
B72205S2251K101 TDK EPCOS	VARISTOR 390V 800A DISC 5MM	1287
B72241L0441K100 TDK EPCOS	VARISTOR 715V 50KA DISC 40MM	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