TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
B72220S2381K101 TDK EPCOS	VARISTOR 620V 10KA DISC 20MM	0
B72540E3140S272 TDK EPCOS	VARISTOR 24.5V 1.2KA 2220	0
B72207S0171K101 TDK EPCOS	VARISTOR 270V 1.2KA DISC 7MM	2300
B72242L0271K102 TDK EPCOS	VARISTOR 430V 65KA ENCASED DISC	0
B72220S2271K101 TDK EPCOS	VARISTOR 430V 10KA DISC 20MM	0
B72214S0140K551 TDK EPCOS	VARISTOR 22V 1KA DISC 14MM	0
B72210S0131K551 TDK EPCOS	VARISTOR 205V 2.5KA DISC 10MM	994
B72650M1140K072 TDK EPCOS	VARISTOR 22V 100A 2SMD JLEAD	0
B72225S4301K101 TDK EPCOS	VARISTOR 470V 20KA DISC 27.5MM	1017
B72205S0350K111 TDK EPCOS	VARISTOR 56V 100A DISC 5MM	768
B72214S0511K101 TDK EPCOS	VARISTOR 820V 4.5KA DISC 14MM	5621
B72220S0750K551 TDK EPCOS	VARISTOR 120V 6.5KA DISC 20MM	0
B72520E0300K062 TDK EPCOS	VARISTOR 47V 200A 1206	6695
B72205S0600K211 TDK EPCOS	VARISTOR 100V 400A DISC 5MM	0
B72207S2321K311 TDK EPCOS	VARISTOR 510V 1.75KA DISC 7MM	4950
B72210S0111K151 TDK EPCOS	VARISTOR 180V 2.5KA DISC 10MM	2351
B72240L0681K100 TDK EPCOS	VARISTOR 1.1KV 40KA SQU 37.5MM	0
B72207S2271K101 TDK EPCOS	VARISTOR 430V 1.75KA DISC 7MM	1355
B72220S0400K551 TDK EPCOS	VARISTOR 68V 2KA DISC 20MM	0
B72210S0271K341 TDK EPCOS	VARISTOR 430V 2.5KA DISC 10MM	3760

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