TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
B72207S0140K101 TDK EPCOS	VARISTOR 22V 250A DISC 7MM	10787
B72510E0200K062 TDK EPCOS	VARISTOR 33V 80A 0805	7401
B72240L0321K100 TDK EPCOS	VARISTOR 510V 40KA SQUARE 37.5MM	0
B72207S0231K111 TDK EPCOS	VARISTOR 360V 1.2KA DISC 7MM	2935
B72240L0141K100 TDK EPCOS	VARISTOR 220V 40KA SQUARE 37.5MM	0
B72580T0600K062 TDK EPCOS	VARISTOR 100V 400A 1812	4644
B72214S0110K101 TDK EPCOS	VARISTOR 18V 1KA DISC 14MM	1709
B72540T0080L062 TDK EPCOS	VARISTOR 15V 1.2KA 2220	0
B72207S0251K111 TDK EPCOS	VARISTOR 390V 1.2KA DISC 7MM	4570
B72530T0060M062 TDK EPCOS	VARISTOR 11V 300A 1210	5133
B72242L0421K102 TDK EPCOS	VARISTOR 680V 65KA ENCASED DISC	0
B72210S2271K551 TDK EPCOS	VARISTOR 510V 4.5KA DISC 14MM	6000
B72210U2151K501 TDK EPCOS	VARISTOR 240V 3.5KA DISC 10MM	1072
B72225S4511K101 TDK EPCOS	VARISTOR 820V 20KA DISC 27.5MM	681
B72240B0381K001 TDK EPCOS	VARISTOR 620V 40KA ENCASED DISC	24
B72250L0251K102 TDK EPCOS	VARISTOR 390V 75KA DISC 57MM	0
B72542V0250K062 TDK EPCOS	VARISTOR 39V 1.2KA 2220	304
B72220S0250K101 TDK EPCOS	VARISTOR 39V 2KA DISC 20MM	1049
B72540E0350K062 TDK EPCOS	VARISTOR 56V 1KA 2220	865
B72214S0131K101 TDK EPCOS	VARISTOR 205V 4.5KA DISC 14MM	1035

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