TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
B72210S0300K151 TDK EPCOS	VARISTOR 47V 500A DISC 10MM	2975
B72220W2131K101 TDK EPCOS	VARISTOR 205V 10KA DISC 23MM	181
B72590D0120H060 TDK EPCOS	VARISTOR 0402	1816
B72580E0250K062 TDK EPCOS	VARISTOR 39V 800A 1812	5251
B72220S2301K101 TDK EPCOS	VARISTOR 470V 10KA DISC 20MM	0
B72650M0141K072 TDK EPCOS	VARISTOR 220V 400A 2SMD JLEAD	5836
B72650M0250K072 TDK EPCOS	VARISTOR 39V 100A 2SMD JLEAD	2117
B72220Q0321K101 TDK EPCOS	VARISTOR 510V 15KA RADIAL	1420
B72207S0600K111 TDK EPCOS	VARISTOR 100V 1.2KA DISC 7MM	6024
B72214P2171K102 TDK EPCOS	14MM, 175VAC, 10%, ADVANCED MP C	2783
B72214T2151K101 TDK EPCOS	VARISTOR 240V 6KA RADIAL BOX 3LD	0
B72510E0170K062 TDK EPCOS	VARISTOR 27V 120A 0805	865
B72207S0110K101 TDK EPCOS	VARISTOR 18V 250A DISC 7MM	9799
B72241L0151K100 TDK EPCOS	VARISTOR 240V 50KA ENCASED DISC	0
B72530V0500K062 TDK EPCOS	VARISTOR 82V 200A 1210	0
B72240B0551K001 TDK EPCOS	VARISTOR 910V 40KA ENCASED DISC	79
B72220S3171K101 TDK EPCOS	VARISTOR 270V 12KA DISC 20MM	0
B72225T4421K101 TDK EPCOS	VARISTOR 680V 20KA RADIAL BOX	0
B72220S0171K101 TDK EPCOS	VARISTOR 270V 8KA DISC 20MM	465
B72520G0170K062 TDK EPCOS	CT1206K17G_G	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