TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
B72214T2171K105 TDK EPCOS	VARISTOR 270V 6KA 3SIP	0
B72207S0111K211 TDK EPCOS	VARISTOR 180V 1.2KA DISC 7MM	8976
B72207S2171K101 TDK EPCOS	VARISTOR 270V 1.75KA DISC 7MM	4172
B72520G1140S862 TDK EPCOS	AECQ200,VW80808-2, 200A,16V,1206	5965
B72214S0301K501 TDK EPCOS	VARISTOR 470V 4.5KA DISC 14MM	0
B72214S2381K101 TDK EPCOS	VARISTOR 620V 5KA DISC 14MM	23301
B72214S2511K101 TDK EPCOS	VARISTOR 820V 5KA DISC 14MM	0
B72210S0251K151 TDK EPCOS	VARISTOR 390V 2.5KA DISC 10MM	1256
B72214S0421K151 TDK EPCOS	VARISTOR 750V 4.5KA DISC 14MM	1636
B72590T7271V60 TDK EPCOS	VARISTOR 310V 0402	29000
B72205S0461K311 TDK EPCOS	VARISTOR 750V 400A DISC 5MM	4948
B72220R2271K101 TDK EPCOS	VARISTOR 430V 10KA DISC 23MM	744
B72650M0400K072 TDK EPCOS	VARISTOR 68V 100A 2SMD JLEAD	185
B72214Q0551K101 TDK EPCOS	VARISTOR 910V 6KA DISC 14MM	0
B72214S0300K551 TDK EPCOS	VARISTOR 47V 1KA DISC 14MM	3695
B72207S1140K111 TDK EPCOS	VARISTOR 22V 250A DISC 7MM	11855
B72210S0200K101 TDK EPCOS	VARISTOR 33V 500A DISC 10MM	3972
B72220P3131K101 TDK EPCOS	VARISTOR 205V 12KA DISC 20MM	0
B72500T0070K060 TDK EPCOS	VARISTOR 12.5V 30A 0603	8093
B72207U2271K501 TDK EPCOS	VARISTOR 430V 1.75KA DISC 7MM	3599

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