TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
B72240L0751K102 TDK EPCOS	VARISTOR 1.2KV 40KA SQU 37.5MM	70
B72520T0060M062 TDK EPCOS	VARISTOR 11V 200A 1206	6928
B72220T2251K105 TDK EPCOS	VARISTOR 390V 10KA RADIAL BOX	0
B72530V0350K062 TDK EPCOS	VARISTOR 56V 250A 1210	22
B72210S2271K101 TDK EPCOS	VARISTOR 430V 3.5KA DISC 10MM	14701
B72210S0950K551 TDK EPCOS	VARISTOR 150V 2.5KA DISC 10MM	0
B72220S2621K101 TDK EPCOS	VARISTOR 1KV 10KA DISC 20MM	0
B72207S0271K211 TDK EPCOS	VARISTOR 430V 1.2KA DISC 7MM	98
B72205S0350K211 TDK EPCOS	VARISTOR 56V 100A DISC 5MM	12135
B72214S2211K101 TDK EPCOS	VARISTOR 330V 6KA DISC 14MM	34
B72214T2131K105 TDK EPCOS	VARISTOR 205V 6KA 3SIP	0
B72580E0200K062 TDK EPCOS	VARISTOR 33V 800A 1812	767
B72735D0050H062 TDK EPCOS	VARISTOR 52V 1012	4008
B72660M0400K072 TDK EPCOS	VARISTOR 68V 250A 2SMD JLEAD	2586
B72214S0681K351 TDK EPCOS	VARISTOR 1.1KV 4.5KA DISC 14MM	0
B72210S1170K552 TDK EPCOS	VARISTOR 27V 500A DISC 10MM	0
B72207S0300K211 TDK EPCOS	VARISTOR 47V 250A DISC 7MM	6767
B72214S0621K101 TDK EPCOS	VARISTOR 1KV 4.5KA DISC 14MM	5562
B72207S0251K101 TDK EPCOS	VARISTOR 390V 1.2KA DISC 7MM	2322
B72220Q0211K101 TDK EPCOS	VARISTOR 330V 15KA RADIAL	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