TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
B72232B0381K001 TDK EPCOS	VARISTOR 620V 25KA ENCASED DISC	16
B72214S0131K151 TDK EPCOS	VARISTOR 205V 4.5KA DISC 14MM	1407
B72220S2171K101 TDK EPCOS	VARISTOR 270V 10KA DISC 20MM	10567
B72241L0421K100 TDK EPCOS	VARISTOR 680V 50KA ENCASED DISC	0
B72214T2381K101 TDK EPCOS	VARISTOR 620V 6KA 3SIP	0
B72210S0271K551 TDK EPCOS	VARISTOR 430V 2.5KA DISC 10MM	358
B72214S0231K101 TDK EPCOS	VARISTOR 360V 4.5KA DISC 14MM	478
B72500E5250L060 TDK EPCOS	VARISTOR 61V 5A 0603	0
B72210S2251K101 TDK EPCOS	VARISTOR 390V 3.5KA DISC 10MM	350
B72520T500K84 TDK EPCOS	VARISTOR 82V 100A 1206	0
B72520G0300K062 TDK EPCOS	CT1206K30G_G	0
B72520T0200K062 TDK EPCOS	VARISTOR 33V 200A 1206	2913
B72220R2301K101 TDK EPCOS	VARISTOR 470V 10KA DISC 23MM	141
B72207S0400K101 TDK EPCOS	VARISTOR 68V 250A DISC 7MM	1994
B72520V0300K062 TDK EPCOS	VARISTOR 47V 200A 1206	0
B72210S0461K331 TDK EPCOS	VARISTOR 750V 2.5KA DISC 10MM	2000
B72210S1170K102 TDK EPCOS	VARISTOR 27V 500A DISC 10MM	2509
B72260B0751K001 TDK EPCOS	VARISTOR 1.2KV 70KA ENCASED DISC	132
B72214P2421K104 TDK EPCOS	14MM, 420VAC, 10%, ADVANCED MP C	0
B72205S0200K101 TDK EPCOS	VARISTOR 33V 100A DISC 5MM	379

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