TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
B72220S2381K501 TDK EPCOS	VARISTOR 620V 10KA DISC 20MM	1140
B72205S0400K111 TDK EPCOS	VARISTOR 68V 100A DISC 5MM	0
B72214S1170K152 TDK EPCOS	VARISTOR 27V 1KA DISC 14MM	0
B72205S0251K111 TDK EPCOS	VARISTOR 390V 400A DISC 5MM	976
B72210S0251K551 TDK EPCOS	VARISTOR 390V 2.5KA DISC 10MM	38
B72205S0950K211 TDK EPCOS	VARISTOR 150V 400A DISC 5MM	0
B72510E2170K072 TDK EPCOS	VARISTOR 29V 30A 0805	0
B72580T6111K072 TDK EPCOS	VARISTOR 180V 250A 1812	0
B72660M0111K072 TDK EPCOS	VARISTOR 180V 1.2KA 2SMD JLEAD	2723
B72207S2141K101 TDK EPCOS	VARISTOR 220V 1.75KA DISC 7MM	514
B72214S0151K151 TDK EPCOS	VARISTOR 240V 4.5KA DISC 14MM	3188
B72520T0170K062 TDK EPCOS	VARISTOR 27V 200A 1206	3998
B72500D0300H060 TDK EPCOS	VARISTOR 50V 0603	212235
B72220P3551K101 TDK EPCOS	VARISTOR 910V 10KA DISC 23MM	1573
B72214S1300K151 TDK EPCOS	VARISTOR 47V 1KA DISC 14MM	0
B72210S0200K151 TDK EPCOS	VARISTOR 33V 500A DISC 10MM	0
B72214T2351K105 TDK EPCOS	VARISTOR 560V 6KA 3SIP	0
B72650M0271K094 TDK EPCOS	VARISTOR 430V 400A 3225	0
B72214S2271K101 TDK EPCOS	VARISTOR 430V 6KA DISC 14MM	5947
B72225M0321M201 TDK EPCOS	25MM, 320V, 20KA, THERMO FUSE TY	380

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