TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
B72214S0461K101 TDK EPCOS	VARISTOR 750V 4.5KA DISC 14MM	736
B72240B0751K001 TDK EPCOS	VARISTOR 1.2KV 40KA ENCASED DISC	18
B72660M0500K093 TDK EPCOS	VARISTOR 82V 1.2KA 4032	0
B72205S0171K111 TDK EPCOS	VARISTOR 270V 400A DISC 5MM	5702
B72205S0301K101 TDK EPCOS	VARISTOR 470V 400A DISC 5MM	6426
B72220S0321K101 TDK EPCOS	VARISTOR 510V 8KA DISC 20MM	551
B72520T0300K072 TDK EPCOS	VARISTOR 47V 200A 1206	0
B72220P3621K101 TDK EPCOS	VARISTOR 1KV 10KA DISC 20MM	2748
B72220S0170K551 TDK EPCOS	VARISTOR 27V 2KA DISC 20MM	0
B72580T0060M062 TDK EPCOS	VARISTOR 11V 500A 1812	0
B72210S0300K551 TDK EPCOS	VARISTOR 47V 500A DISC 10MM	184
B72220P3151K101 TDK EPCOS	VARISTOR 240V 12KA DISC 20MM	1130
B72520G0250K062 TDK EPCOS	CT1206K25G_G	0
B72210S0271K531 TDK EPCOS	VARISTOR 430V 2.5KA DISC 10MM	5474
B72220Q0231K101 TDK EPCOS	VARISTOR 360V 15KA RADIAL	681
B72214S2381K501 TDK EPCOS	VARISTOR 620V 5KA DISC 14MM	0
B72210S1140K551 TDK EPCOS	VARISTOR 22V 500A DISC 10MM	1444
B72580V0140K062 TDK EPCOS	VARISTOR 22V 800A 1812	7898
B72214S0200K551 TDK EPCOS	VARISTOR 33V 1KA DISC 14MM	2750
B72240L0151K102 TDK EPCOS	VARISTOR 240V 40KA SQUARE 37.5MM	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