TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
B72220R2321K101 TDK EPCOS	VARISTOR 510V 10KA DISC 23MM	426
B72220P3461K101 TDK EPCOS	VARISTOR 750V 12KA DISC 20MM	250
B72210S0250K551 TDK EPCOS	VARISTOR 39V 500A DISC 10MM	0
B72520E1250K062 TDK EPCOS	VARISTOR 39V 200A 1206	2008
B72207S0131K211 TDK EPCOS	VARISTOR 205V 1.2KA DISC 7MM	453
B72580T0400K062 TDK EPCOS	VARISTOR 68V 500A 1812	203
B72590E0170S160 TDK EPCOS	VARISTOR 32.5V 6A 0402	0
B72214P2421K101 TDK EPCOS	VARISTOR 680V 6KA DISC 14MM	977
B72240L0461K102 TDK EPCOS	VARISTOR 750V 40KA SQUARE 37.5MM	398
B72650M0750K072 TDK EPCOS	VARISTOR 120V 400A 3225	2356
B72210P2271K101 TDK EPCOS	VARISTOR 430V 3.5KA DISC 10MM	337
B72214S2421K551 TDK EPCOS	VARISTOR 680V 5KA DISC 14MM	2980
B72240B0151K001 TDK EPCOS	VARISTOR 240V 40KA ENCASED DISC	18
B72214T2321K105 TDK EPCOS	VARISTOR 510V 6KA 3SIP	82
B72214T2351K101 TDK EPCOS	VARISTOR 560V 6KA 3SIP	0
B72220S0140K101 TDK EPCOS	VARISTOR 22V 2KA DISC 20MM	323
B72205S0251K101 TDK EPCOS	VARISTOR 390V 400A DISC 5MM	13814
B72207S0200K211 TDK EPCOS	VARISTOR 33V 250A DISC 7MM	11964
B72210S0151K101 TDK EPCOS	VARISTOR 240V 2.5KA DISC 10MM	2490
B72542V6500K062 TDK EPCOS	VARISTOR 82V 4.5KA 2220	616

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