TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
B72520T0110K062 TDK EPCOS	VARISTOR 18V 200A 1206	1031
B72660M0140K072 TDK EPCOS	VARISTOR 22V 250A 2SMD JLEAD	6280
B72240B0131K001 TDK EPCOS	VARISTOR 205V 40KA ENCASED DISC	708
B72214P2151K101 TDK EPCOS	VARISTOR 240V 6KA DISC 14MM	108
B72240B0231K001 TDK EPCOS	VARISTOR 360V 40KA ENCASED DISC	321
B72225S4171K101 TDK EPCOS	VARISTOR 270V 20KA DISC 27.5MM	0
B72660M1170K072 TDK EPCOS	VARISTOR 27V 250A 2SMD JLEAD	0
B72207U2151K501 TDK EPCOS	VARISTOR 240V 1.75KA DISC 7MM	3275
B72214S0551K101 TDK EPCOS	VARISTOR 910V 4.5KA DISC 14MM	6529
B72220Q0421K101 TDK EPCOS	VARISTOR 680V 15KA DISC 20MM	1580
B72650M0111K072 TDK EPCOS	VARISTOR 180V 400A 2SMD JLEAD	2311
B72220Q0301K101 TDK EPCOS	VARISTOR 470V 15KA RADIAL	523
B72520T0250K062 TDK EPCOS	VARISTOR 39V 200A 1206	32197
B72207S0141K111 TDK EPCOS	VARISTOR 220V 1.2KA DISC 7MM	38490
B72520G0140K062 TDK EPCOS	CT1206K14G_G	0
B72210S0170K101 TDK EPCOS	VARISTOR 27V 500A DISC 10MM	3402
B72214S0600K101 TDK EPCOS	VARISTOR 100V 4.5KA DISC 14MM	3811
B72590D0050H260 TDK EPCOS	VARISTOR 0402	9964
B72240L0551K100 TDK EPCOS	VARISTOR 910V 40KA SQUARE 37.5MM	722
B72230M0381M401 TDK EPCOS	30MM, 385V, 25KA, THERMO FUSE TY	400

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