TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
B72214R2301K101 TDK EPCOS	VARISTOR 470V 6KA DISC 17MM	0
B72240B0750K001 TDK EPCOS	VARISTOR 120V 25KA ENCASED DISC	105
B72240L0681K102 TDK EPCOS	VARISTOR 680VRMS 40MM W/STR TABS	244
B72220U3321K502 TDK EPCOS	20MM, 320VAC, 10% SUPERIOR, 125D	0
B72220S0421K551 TDK EPCOS	VARISTOR 680V 8KA DISC 20MM	254
B72225M0321M301 TDK EPCOS	25MM, 320V, 20KA, THERMO FUSE TY	400
B72214S0141K101 TDK EPCOS	VARISTOR 220V 4.5KA DISC 14MM	2275
B72214S2271K551 TDK EPCOS	VARISTOR 430V 6KA DISC 14MM	1410
B72210U2271K501 TDK EPCOS	VARISTOR 430V 3.5KA DISC 10MM	690
B72530T6170K062 TDK EPCOS	EIA1210, 24VDC, HIGH SURGE 2000A	5147
B72205S0171K211 TDK EPCOS	VARISTOR 270V 400A DISC 5MM	0
B72225T4301K101 TDK EPCOS	VARISTOR 470V 20KA RADIAL BOX	1500
B72240L0441K102 TDK EPCOS	VARISTOR 715V 40KA SQUARE 37.5MM	0
B72210S0600K151 TDK EPCOS	VARISTOR 100V 2.5KA DISC 10MM	5397
B72214S0111K101 TDK EPCOS	VARISTOR 180V 4.5KA DISC 14MM	4704
B72260B0461K001 TDK EPCOS	VARISTOR 750V 70KA ENCASED DISC	46
B72530T0400K062 TDK EPCOS	VARISTOR 68V 250A 1210	9989
B72280B0151K001 TDK EPCOS	VARISTOR 240V 100KA ENCASED DISC	26
B72220P3141K101 TDK EPCOS	VARISTOR 220V 12KA DISC 20MM	0
B72214S0350K101 TDK EPCOS	VARISTOR 56V 1KA DISC 14MM	47413

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