TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
B72214S0621K351 TDK EPCOS	VARISTOR 1KV 4.5KA DISC 14MM	0
B72207S0231K311 TDK EPCOS	VARISTOR 360V 1.2KA DISC 7MM	4380
B72220S3231K101 TDK EPCOS	VARISTOR 360V 12KA DISC 20MM	1502
B72220R2251K101 TDK EPCOS	VARISTOR 390V 10KA DISC 23MM	160
B72214S1140K102 TDK EPCOS	VARISTOR 22V 1KA DISC 14MM	2992
B72210S0231K151 TDK EPCOS	VARISTOR 360V 2.5KA DISC 10MM	2890
B72214S0111K151 TDK EPCOS	VARISTOR 180V 4.5KA DISC 14MM	0
B72590D0050A060 TDK EPCOS	VARISTOR 6.4V 10A 0402	760419
B72210S2271K111 TDK EPCOS	VARISTOR 430V 3.5KA DISC 10MM	6000
B72510T5040M60 TDK EPCOS	VARISTOR 0805	0
B72214U2321K502 TDK EPCOS	14MM, 320VAC, 10% ADVANCED, 125D	2817
B72214P2461K101 TDK EPCOS	VARISTOR 750V 6KA DISC 14MM	2820
B72225S4321K101 TDK EPCOS	VARISTOR 510V 20KA DISC 27.5MM	738
B72210S2321K101 TDK EPCOS	VARISTOR 510V 3.5KA DISC 10MM	1255
B72220S0200K101 TDK EPCOS	VARISTOR 33V 2KA DISC 20MM	1262
B72207S0140K111 TDK EPCOS	VARISTOR 22V 250A DISC 7MM	6000
B72214S0321K531 TDK EPCOS	VARISTOR 510V 4.5KA DISC 14MM	2500
B72214P2131K102 TDK EPCOS	14MM, 130VAC, 10%, ADVANCED MP C	2466
B72205S0111K211 TDK EPCOS	VARISTOR 180V 400A DISC 5MM	0
B72210S0231K551 TDK EPCOS	VARISTOR 360V 2.5KA DISC 10MM	0

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