TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
B72220S0441K101 TDK EPCOS	VARISTOR 715V 8KA DISC 20MM	14388
B72225M0381M201 TDK EPCOS	25MM, 385V, 20KA, THERMO FUSE TY	0
B72220S0621K101 TDK EPCOS	VARISTOR 1KV 6.5KA DISC 20MM	818
B72207S2251K101 TDK EPCOS	VARISTOR 390V 1.75KA DISC 7MM	23316
B72214S0300K101 TDK EPCOS	VARISTOR 47V 1KA DISC 14MM	2506
B72210S0421K331 TDK EPCOS	VARISTOR 680V 2.5KA DISC 10MM	498
B72214T2301K105 TDK EPCOS	VARISTOR 470V 6KA 3SIP	120
B72214P2461K102 TDK EPCOS	14MM, 460VAC, 10%, ADVANCED MP C	3875
B72530T0040M062 TDK EPCOS	VARISTOR 8V 250A 1210	7234
B72240B0461K001 TDK EPCOS	VARISTOR 750V 40KA ENCASED DISC	218
B72205S0301K111 TDK EPCOS	VARISTOR 470V 400A DISC 5MM	717
B72542V3140S572 TDK EPCOS	VARISTOR 25V 12KA 2220	0
B72225T4131K101 TDK EPCOS	VARISTOR 205V 20KA RADIAL BOX	0
B72205S0271K211 TDK EPCOS	VARISTOR 430V 400A DISC 5MM	22500
B72530T600K72 TDK EPCOS	VARISTOR 100V 200A 1210	0
B72210S0170K551 TDK EPCOS	VARISTOR 27V 500A DISC 10MM	0
B72242L0271K100 TDK EPCOS	VARISTOR 430V 65KA ENCASED DISC	0
B72205S2211K101 TDK EPCOS	VARISTOR 330V 800A DISC 5MM	0
B72214P2381K101 TDK EPCOS	VARISTOR 620V 6KA DISC 14MM	6011
B72207S0170K201 TDK EPCOS	VARISTOR 27V 250A DISC 7MM	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