TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
B72205S0250K211 TDK EPCOS	VARISTOR 39V 100A DISC 5MM	3000
B72220Q0461K101 TDK EPCOS	VARISTOR 750V 15KA DISC 20MM	0
B72260B0551K001 TDK EPCOS	VARISTOR 910V 70KA ENCASED DISC	45
B72510E0350K062 TDK EPCOS	VARISTOR 56V 80A 0805	0
B72590T0140L060 TDK EPCOS	VARISTOR 23.5V 20A 0402	70186
B72214S0271K131 TDK EPCOS	VARISTOR 430V 4.5KA DISC 14MM	1244
B72205S0321K101 TDK EPCOS	5MM, 320VAC, 10%, STANDARD	0
B72214P2511K101 TDK EPCOS	VARISTOR 820V 6KA DISC 14MM	10959
B72540T6500K062 TDK EPCOS	VARISTOR 82V 4.5KA 2220	4146
B72210S0231K101 TDK EPCOS	VARISTOR 360V 2.5KA DISC 10MM	6994
B72220W2271K101 TDK EPCOS	VARISTOR 430V 10KA DISC 23MM	178
B72207S2131K101 TDK EPCOS	VARISTOR 205V 1.75KA DISC 7MM	4798
B72220S2251K101 TDK EPCOS	VARISTOR 390V 10KA DISC 20MM	2435
B72580T6750K072 TDK EPCOS	VARISTOR 120V 400A 1812	0
B72207S2271K311 TDK EPCOS	VARISTOR 430V 1.75KA DISC 7MM	4645
B72240L0141K102 TDK EPCOS	VARISTOR 220V 40KA SQUARE 37.5MM	0
B72250L0151K100 TDK EPCOS	VARISTOR 240V 75KA DISC 57MM	0
B72214S1390K501 TDK EPCOS	VARISTOR 65V DISC 14MM	0
B72530V0400K062 TDK EPCOS	VARISTOR 68V 250A 1210	16907
B72220X2271K501 TDK EPCOS	VARISTOR 430V 10KA DISC 20MM	2687

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