TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
B72220P3211K101 TDK EPCOS	VARISTOR 330V 12KA DISC 20MM	0
B72242L0421K100 TDK EPCOS	VARISTOR 680V 65KA ENCASED DISC	0
B72205S0200K111 TDK EPCOS	VARISTOR 33V 100A DISC 5MM	2309
B72225S4581K101 TDK EPCOS	VARISTOR 940V 20KA DISC 27.5MM	0
B72214T2251K105 TDK EPCOS	VARISTOR 390V 3KA RADIAL BOX 3LD	0
B72500E8140S160 TDK EPCOS	VARISTOR 28V 5A 0603	1114
B72500D0200A060 TDK EPCOS	VARISTOR 25V 30A 0603	48267
B72214S2551K151 TDK EPCOS	VARISTOR 910V 5KA DISC 14MM	1500
B72214Q0231K101 TDK EPCOS	VARISTOR 360V 8KA RADIAL	2351
B72530U1600K062 TDK EPCOS	EIA1210, 85VDC, HIGH SURGE 1200A	4844
B72214S0251K551 TDK EPCOS	VARISTOR 390V 4.5KA DISC 14MM	3452
B72240L0131K102 TDK EPCOS	VARISTOR 130VRMS 40MM W/STR TABS	0
B72225S4141K101 TDK EPCOS	VARISTOR 220V 20KA DISC 27.5MM	0
B72500E0250K060 TDK EPCOS	VARISTOR 39V 30A 0603	7240
B72250L0551K102 TDK EPCOS	VARISTOR 910V 75KA DISC 57MM	0
B72520T0500K062 TDK EPCOS	VARISTOR 82V 100A 1206	12798
B72540T0040M062 TDK EPCOS	VARISTOR 8V 1KA 2220	0
B72240L0381K100 TDK EPCOS	VARISTOR 385VRMS 40MM W/TABS	0
B72210S0400K551 TDK EPCOS	VARISTOR 68V 500A DISC 10MM	0
B72225M0271M201 TDK EPCOS	25MM, 275V, 20KA, THERMO FUSE TY	154

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