TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
B72214S0750K101 TDK EPCOS	VARISTOR 120V 4.5KA DISC 14MM	681
B72650M0350K093 TDK EPCOS	VARISTOR 56V 100A 3225	0
B72214S0681K331 TDK EPCOS	VARISTOR 1.1KV 4.5KA DISC 14MM	4160
B72210S0500K151 TDK EPCOS	VARISTOR 82V 2.5KA DISC 10MM	2880
B72214S0200K151 TDK EPCOS	VARISTOR 33V 1KA DISC 14MM	4133
B72220U3381K501 TDK EPCOS	20MM, 385VAC, 10% SUPERIOR, 125D	2880
B72530G0140K062 TDK EPCOS	CT1210K14G_G	0
B72205S0400K101 TDK EPCOS	VARISTOR 68V 100A DISC 5MM	4787
B72724D0160H062 TDK EPCOS	VARISTOR 80V 0612	4033
B72220T2421K105 TDK EPCOS	VARISTOR 680V 10KA RADIAL BOX	0
B72214S0200K101 TDK EPCOS	VARISTOR 33V 1KA DISC 14MM	2910
B72220Q0251K101 TDK EPCOS	VARISTOR 390V 15KA RADIAL	0
B72220S0461K101 TDK EPCOS	VARISTOR 750V 8KA DISC 20MM	2859
B72660M0151K072 TDK EPCOS	VARISTOR 240V 1.2KA 2SMD JLEAD	9960
LS40K440QP TDK EPCOS	VARISTOR 715V 40KA ENCASED DISC	0
B72650M0131K072 TDK EPCOS	VARISTOR 205V 400A 2SMD JLEAD	17554
B72520E0140K062 TDK EPCOS	VARISTOR 22V 200A 1206	749
B72214P2681K101 TDK EPCOS	VARISTOR 1.1KV 6KA DISC 17MM	77
B72242L0321K102 TDK EPCOS	VARISTOR 510V 65KA ENCASED DISC	0
B72220S0681K101 TDK EPCOS	VARISTOR 1.1KV 6.5KA DISC 20MM	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