TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
B72500D0090A060 TDK EPCOS	VARISTOR 10V 30A 0603	22585
B72220S2141K101 TDK EPCOS	VARISTOR 220V 10KA DISC 20MM	0
B72260B0251K001 TDK EPCOS	VARISTOR 390V 70KA ENCASED DISC	6
B72225S4681K101 TDK EPCOS	VARISTOR 1.1KV 20KA DISC 27.5MM	0
B72530G0300K062 TDK EPCOS	CT1210K30G_G	0
B72590T8140S160 TDK EPCOS	VARISTOR 28V 2A 0402	29220
B72205S0141K211 TDK EPCOS	VARISTOR 220V 400A DISC 5MM	1275
B72214T2211K101 TDK EPCOS	VARISTOR 330V 6KA 3SIP	0
B72210S0350K151 TDK EPCOS	VARISTOR 56V 500A DISC 10MM	3168
B72220S1140K102 TDK EPCOS	VARISTOR 22V 2KA DISC 20MM	1430
B72205S2231K101 TDK EPCOS	VARISTOR 360V 800A DISC 5MM	1000
B72214S0381K151 TDK EPCOS	VARISTOR 620V 4.5KA DISC 14MM	1092
B72220T2231K101 TDK EPCOS	VARISTOR 360V 10KA RADIAL BOX	0
B72205S0250K111 TDK EPCOS	VARISTOR 39V 100A DISC 5MM	23
B72580T0950S172 TDK EPCOS	VARISTOR 165V 1812	0
B72220S1170K102 TDK EPCOS	VARISTOR 27V 2KA DISC 20MM	132
B72205S0301K311 TDK EPCOS	VARISTOR 470V 400A DISC 5MM	36
B72530E0350K062 TDK EPCOS	VARISTOR 56V 250A 1210	0
B72220S2131K101 TDK EPCOS	VARISTOR 205V 10KA DISC 20MM	1168
B72205S2271K101 TDK EPCOS	VARISTOR 430V 800A DISC 5MM	287

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