TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
B72540T6500S162 TDK EPCOS	VARISTOR 77.5V 4.5KA 2220	1383
B72220S0400K101 TDK EPCOS	VARISTOR 68V 2KA DISC 20MM	36364
B72207S0211K101 TDK EPCOS	VARISTOR DISC 7MM	0
B72650M0151K072 TDK EPCOS	VARISTOR 240V 400A 2SMD JLEAD	30807
B72214U2511K501 TDK EPCOS	VARISTOR 820V 5KA DISC 14MM	300
B72207S0381K101 TDK EPCOS	VARISTOR 620V 1.2KA DISC 7MM	10433
B72210S2131K101 TDK EPCOS	VARISTOR 205V 3.5KA DISC 10MM	3222
B72210S0350K551 TDK EPCOS	VARISTOR 56V 500A DISC 10MM	0
B72214S0421K101 TDK EPCOS	VARISTOR 680V 4.5KA DISC 14MM	2675
B72500T0040M060 TDK EPCOS	VARISTOR 8V 30A 0603	9023
B72205S0600K311 TDK EPCOS	VARISTOR 100V 400A DISC 5MM	0
B72214T2421K101 TDK EPCOS	VARISTOR 680V 6KA RADIAL BOX 3LD	0
B72540E1140S262 TDK EPCOS	VARISTOR 24.5V 1.2KA 2220	3012
B72510E9200S172 TDK EPCOS	VARISTOR 34.5V 80A 0805	11750
B72210S0421K501 TDK EPCOS	VARISTOR 680V 2.5KA DISC 10MM	0
B72214P2301K103 TDK EPCOS	14MM, 300VAC, 10%, ADVANCED MP C	2223
B72530T0350K062 TDK EPCOS	VARISTOR 56V 250A 1210	161
B72220S0350K101 TDK EPCOS	VARISTOR 56V 2KA DISC 20MM	19477
B72214S0251K501 TDK EPCOS	VARISTOR 390V 4.5KA DISC 14MM	0
B72660M0231K093 TDK EPCOS	VARISTOR 1.2KA 4032	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