TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
B72250L0321K100 TDK EPCOS	VARISTOR 510V 75KA DISC 57MM	0
B72207S0271K111 TDK EPCOS	VARISTOR 430V 1.2KA DISC 7MM	0
B72260B0131K001 TDK EPCOS	VARISTOR 205V 70KA ENCASED DISC	13
B72520G0200K062 TDK EPCOS	CT1206K20G_G	0
B72210S0461K551 TDK EPCOS	VARISTOR 750V 2.5KA DISC 10MM	1460
B72220T2321K105 TDK EPCOS	VARISTOR 510V 10KA RADIAL BOX	444
B72660M0131K093 TDK EPCOS	VARISTOR 205V 1.2KA 2SMD JLEAD	1931
B72225T4231K101 TDK EPCOS	VARISTOR 360V 20KA RADIAL BOX	0
B72530E0140K062 TDK EPCOS	VARISTOR 22V 400A 1210	6461
B72210S1140K552 TDK EPCOS	VARISTOR 22V 500A DISC 10MM	5988
B72214S0321K331 TDK EPCOS	VARISTOR 680V 4.5KA DISC 14MM	2845
B72214U2321K501 TDK EPCOS	VARISTOR 510V 6KA DISC 14MM	0
B72250L0251K100 TDK EPCOS	VARISTOR 390V 75KA DISC 57MM	0
B72241L0131K100 TDK EPCOS	VARISTOR 205V 50KA DISC 40MM	0
B72240L0321K102 TDK EPCOS	VARISTOR 510V 40KA SQUARE 37.5MM	50
B72207S0200K111 TDK EPCOS	VARISTOR 33V 250A DISC 7MM	1303
B72580T0110K062 TDK EPCOS	VARISTOR 18V 800A 1812	0
B72207S0500K211 TDK EPCOS	VARISTOR 82V 1.2KA DISC 7MM	3182
B72580U1500K062 TDK EPCOS	EIA1812, 65VDC, HIGH SURGE 3000A	1450
B72214T2141K101 TDK EPCOS	VARISTOR 220V 6KA 3SIP	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