TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
B72540E0300K062 TDK EPCOS	VARISTOR 47V 1.2KA 2220	1824
B72210S0441K101 TDK EPCOS	VARISTOR 715V 2.5KA DISC 10MM	2772
B72207S2301K101 TDK EPCOS	VARISTOR 470V 1.75KA DISC 7MM	13322
B72580E1140S262 TDK EPCOS	VARISTOR 24.5V 800A 1812	3209
B72232B0461K001 TDK EPCOS	VARISTOR 750V 25KA ENCASED DISC	12
B72510T0250K062 TDK EPCOS	VARISTOR 39V 80A 0805	4443
B72714A8140S160 TDK EPCOS	VARISTOR 28V 2A 0508	2562
B72220R2151K101 TDK EPCOS	VARISTOR 240V 10KA DISC 23MM	93
B72205S0500K111 TDK EPCOS	VARISTOR 82V 400A DISC 5MM	5996
B72207S0301K101 TDK EPCOS	VARISTOR 470V 1.2KA DISC 7MM	22991
B72210S1140K401 TDK EPCOS	VARISTOR 22V 500A DISC 10MM	0
B72207S0271K321 TDK EPCOS	VARISTOR 430V 1.2KA DISC 7MM	5800
B72214Q0321K101 TDK EPCOS	VARISTOR 510V 8KA RADIAL	1640
B72650M0151K093 TDK EPCOS	VARISTOR 240V 400A 2SMD JLEAD	860
B72214S1350K102 TDK EPCOS	VARISTOR DISC 14MM	0
B72214S0351K101 TDK EPCOS	VARISTOR DISC 14MM	2788
B72650M0231K072 TDK EPCOS	VARISTOR 400A 2SMD JLEAD	1100
B72220W2321K101 TDK EPCOS	VARISTOR 510V 10KA DISC 23MM	0
B72205S2271K111 TDK EPCOS	VARISTOR 430V 800A DISC 5MM	0
B72650M0231K093 TDK EPCOS	VARISTOR 400A 3225	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