TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
V140LA20A	RADIAL LEAD VARISTOR	518
B72232B0551K001 TDK EPCOS	VARISTOR 910V 25KA ENCASED DISC	835
B72220S0271K551 TDK EPCOS	VARISTOR 430V 8KA DISC 20MM	704
V251HA40 Wickmann / Littelfuse	VARISTOR 390V 40KA DISC 40MM	44
B72205S0231K101 TDK EPCOS	VARISTOR 360V 400A DISC 5MM	5148
V18ZA05P Wickmann / Littelfuse	VARISTOR 18V 100A DISC 5MM	302
V10H510P Wickmann / Littelfuse	VARISTOR 820V 3.5KA DISC 10MM	0
B72214S0750K151 TDK EPCOS	VARISTOR 120V 4.5KA DISC 14MM	1298
AMCV-0603LC-180-C050Y-T Abracon	VARISTOR 25V 1A 0603	4384
TMOV14RP230ML2T7 Wickmann / Littelfuse	VARISTOR 360V 6KA DISC 14MM	0
V05E42AUTO Wickmann / Littelfuse	VARISTOR 68V 400A DISC 5MM	0
TMOV34S151EP Wickmann / Littelfuse	VARISTOR 240V 40KA SQUARE 34MM	0
V150LA20CP Wickmann / Littelfuse	VARISTOR 240V 10KA DISC 20MM	1500
ERZ-V10D751 Panasonic	VARISTOR 750V 3.5KA DISC 10MM	0
MVR14D621K-S Meritek	VARISTOR 620V 6000A DISC 14MM HI	0
V230LA20CPX2855 Wickmann / Littelfuse	VARISTOR 360V 6.5KA DISC 14MM	0
VP3225K401R130 KEMET	VARISTOR 205V 400A 2SMD JLEAD	0
AMCV-0402-090-C800N-T Abracon	VARISTOR 13.5V 15A 0402	0
V47ZA1P Wickmann / Littelfuse	VARISTOR 47V 250A DISC 7MM	10005
561KD10J Yageo	MOV	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