TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
B72650M0140K072 TDK EPCOS	VARISTOR 22V 100A 3225	2124
B72210S0300K131 TDK EPCOS	VARISTOR 47V 500A DISC 10MM	0
B72220T2131K105 TDK EPCOS	VARISTOR 205V 10KA RADIAL BOX	0
B72214S0140K151 TDK EPCOS	VARISTOR 22V 1KA DISC 14MM	2843
B72220S3151K101 TDK EPCOS	VARISTOR 240V 12KA DISC 20MM	345
B72660M0271K093 TDK EPCOS	VARISTOR 430V 1.2KA 2SMD JLEAD	3214
B72207S2231K101 TDK EPCOS	VARISTOR 360V 1.75KA DISC 7MM	283
B72500D50H160 TDK EPCOS	VARISTOR 150V 0603	19181
B72220S0111K101 TDK EPCOS	VARISTOR 180V 6.5KA DISC 20MM	1521
B72250L0551K100 TDK EPCOS	VARISTOR 910V 75KA DISC 57MM	0
B72500E5170S260 TDK EPCOS	VARISTOR 32.5V 30A 0603	12525
B72500D0150A060 TDK EPCOS	VARISTOR 22V 30A 0603	24330
B72214S0950K551 TDK EPCOS	VARISTOR 150V 4.5KA DISC 14MM	0
B72205S0461K101 TDK EPCOS	VARISTOR 750V 400A DISC 5MM	1858
B72214S0171K151 TDK EPCOS	VARISTOR 270V 4.5KA DISC 14MM	2677
B72510T2170K62 TDK EPCOS	VARISTOR 25V 30A 0805	0
B72214S0301K101 TDK EPCOS	VARISTOR 470V 4.5KA DISC 14MM	0
B72214S0271K151 TDK EPCOS	VARISTOR 430V 4.5KA DISC 14MM	380
B72500E2170S170 TDK EPCOS	VARISTOR 32.5V 30A 0603	0
B72207S0461K321 TDK EPCOS	VARISTOR 750V 1.2KA DISC 7MM	6749

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