TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
B72205S0110K101 TDK EPCOS	VARISTOR 18V 100A DISC 5MM	5341
B72214S0321K151 TDK EPCOS	VARISTOR 510V 4.5KA DISC 14MM	96
B72510T5040M62 TDK EPCOS	VARISTOR 0805	0
B72260B0151K001 TDK EPCOS	VARISTOR 240V 70KA ENCASED DISC	10
B72207S0301K111 TDK EPCOS	VARISTOR 470V 1.2KA DISC 7MM	483
B72207S0500K101 TDK EPCOS	VARISTOR 82V 1.2KA DISC 7MM	0
B72225S4461K101 TDK EPCOS	VARISTOR 750V 20KA DISC 27.5MM	1018
B72214T2131K101 TDK EPCOS	VARISTOR 205V 6KA RADIAL BOX 3LD	0
B72240B0251K001 TDK EPCOS	VARISTOR 390V 40KA ENCASED DISC	85
B72660M0251K072 TDK EPCOS	VARISTOR 390V 1.2KA 2SMD JLEAD	514
B72214S2381K301 TDK EPCOS	VARISTOR 620V 5KA DISC 14MM	0
B72580T0040M062 TDK EPCOS	VARISTOR 8V 500A 1812	0
B72207S0251K211 TDK EPCOS	VARISTOR 390V 1.2KA DISC 7MM	2724
B72205S0251K311 TDK EPCOS	VARISTOR 390V 400A DISC 5MM	1269
B72214Q0681K101 TDK EPCOS	VARISTOR 1.1KV 6KA DISC 14MM	0
B72220P3271K101 TDK EPCOS	VARISTOR 430V 12KA DISC 20MM	1059
B72220S0231K101 TDK EPCOS	VARISTOR 360V 8KA DISC 20MM	4231
B72207S2950K101 TDK EPCOS	VARISTOR DISC 7MM	0
B72520T0500K072 TDK EPCOS	VARISTOR 82V 100A 1206	0
B72590D0160H060 TDK EPCOS	VARISTOR 65V 0402	2190

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