TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
B72500T8250L060 TDK EPCOS	VARISTOR 61V 5A 0603	27207
B72214S0151K551 TDK EPCOS	VARISTOR 240V 4.5KA DISC 14MM	2998
B72220P3231K101 TDK EPCOS	VARISTOR 360V 12KA DISC 20MM	0
B72214S0461K151 TDK EPCOS	VARISTOR 430V 3.5KA DISC 10MM	611
B72214S2301K301 TDK EPCOS	VARISTOR 470V 6KA DISC 14MM	0
B72220S0321K551 TDK EPCOS	VARISTOR 510V 8KA DISC 20MM	1500
B72214P2211K102 TDK EPCOS	14MM, 210VAC, 10%, ADVANCED MP C	2798
B72214Q0301K101 TDK EPCOS	VARISTOR 470V 8KA RADIAL	10205
B72660M0300K072 TDK EPCOS	VARISTOR 47V 250A 2SMD JLEAD	142
B72510T0080L062 TDK EPCOS	VARISTOR 15V 120A 0805	3639
B72214S2351K101 TDK EPCOS	14MM, 350VAC, 10%, ADVANCED	0
B72225S4421K101 TDK EPCOS	VARISTOR 680V 20KA DISC 27.5MM	0
B72240L0231K102 TDK EPCOS	VARISTOR 230VRMS 40MM W/STR TABS	0
B72214S0421K551 TDK EPCOS	VARISTOR 680V 4.5KA DISC 14MM	1000
B72570D0160H060 TDK EPCOS	VARISTOR 38V 1003	12000
B72220S2511K101 TDK EPCOS	VARISTOR 820V 10KA DISC 20MM	0
B72207S0250K101 TDK EPCOS	VARISTOR 39V 250A DISC 7MM	2143
B72214S1140K152 TDK EPCOS	VARISTOR 22V 1KA DISC 14MM	1794
B72207S0141K101 TDK EPCOS	VARISTOR 220V 1.2KA DISC 7MM	4815
B72210S0381K101 TDK EPCOS	VARISTOR 620V 2.5KA DISC 10MM	2388

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