TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
B72240B0271K001 TDK EPCOS	VARISTOR 430V 40KA ENCASED DISC	121
B72500T0110K060 TDK EPCOS	VARISTOR 18V 30A 0603	3204
B72650M0301K093 TDK EPCOS	VARISTOR 470V 400A 2SMD JLEAD	17746
B72214S0950K101 TDK EPCOS	VARISTOR 150V 4.5KA DISC 14MM	83
B72250L0381K100 TDK EPCOS	VARISTOR 620V 75KA DISC 57MM	0
B72205S0500K101 TDK EPCOS	VARISTOR 82V 400A DISC 5MM	9391
B72540T0300K062 TDK EPCOS	VARISTOR 47V 1.2KA 2220	1859
B72510E0140K062 TDK EPCOS	VARISTOR 22V 120A 0805	6663
B72207S0301K201 TDK EPCOS	VARISTOR 470V 1.2KA DISC 7MM	0
B72214S0271K501 TDK EPCOS	VARISTOR 430V 4.5KA DISC 14MM	1269
B72210S2141K101 TDK EPCOS	VARISTOR 220V 3.5KA DISC 10MM	0
B72210S0421K101 TDK EPCOS	VARISTOR 680V 2.5KA DISC 10MM	2530
B72205S0750K211 TDK EPCOS	VARISTOR 120V 400A DISC 5MM	4430
B72210S0750K101 TDK EPCOS	VARISTOR 120V 2.5KA DISC 10MM	1404
B72220T2551K105 TDK EPCOS	VARISTOR 910V 10KA RADIAL BOX	70
B72210S0381K351 TDK EPCOS	VARISTOR 620V 2.5KA DISC 10MM	1900
B72214Q0151K101 TDK EPCOS	VARISTOR 240V 8KA RADIAL	48
B72210S0461K101 TDK EPCOS	VARISTOR 750V 2.5KA DISC 10MM	2634
B72210P2681K101 TDK EPCOS	VARISTOR 1.1KV 3.5KA DISC 10MM	8344
B72260B0102K001 TDK EPCOS	VARISTOR 1.8KV 70KA ENCASED DISC	39

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