TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
B72540T0600K062 TDK EPCOS	VARISTOR 100V 2220	7069
B72210S2251K551 TDK EPCOS	VARISTOR 390V 3.5KA DISC 10MM	926
B72220T2251K101 TDK EPCOS	VARISTOR 390V 10KA RADIAL BOX	0
B72220P3421K101 TDK EPCOS	VARISTOR 680V 12KA DISC 20MM	0
B72220P3251K101 TDK EPCOS	VARISTOR 390V 12KA DISC 20MM	877
B72214Q0251K101 TDK EPCOS	VARISTOR 390V 8KA RADIAL	1068
B72232B0151K001 TDK EPCOS	VARISTOR 240V 25KA ENCASED DISC	14
B72210S2211K101 TDK EPCOS	VARISTOR 330V 3.5KA DISC 10MM	0
B72214S0321K551 TDK EPCOS	VARISTOR 510V 4.5KA DISC 14MM	3896
B72210S0271K101 TDK EPCOS	VARISTOR 430V 2.5KA DISC 10MM	14029
B72214S2171K551 TDK EPCOS	VARISTOR 270V 6KA DISC 14MM	0
B72520T0400K062 TDK EPCOS	VARISTOR 68V 100A 1206	99107
B72210S0170K151 TDK EPCOS	VARISTOR 27V 500A DISC 10MM	6000
B72530E1140S262 TDK EPCOS	VARISTOR 24.5V 400A 1210	11066
B72214S2171K101 TDK EPCOS	VARISTOR 270V 6KA DISC 14MM	26062
B72205S0151K111 TDK EPCOS	VARISTOR 240V 400A DISC 5MM	1196
B72214S0250K551 TDK EPCOS	VARISTOR 39V 1KA DISC 14MM	0
B72510T0110K062 TDK EPCOS	VARISTOR 18V 120A 0805	2929
B72205S0140K111 TDK EPCOS	VARISTOR 22V 100A DISC 5MM	5490
B72660M0950K072 TDK EPCOS	VARISTOR 150V 1.2KA 2SMD JLEAD	464

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