TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
B72210S0461K331 TDK EPCOS	VARISTOR 750V 2.5KA DISC 10MM	2000
ERZ-C32EK201Y Panasonic	VARISTOR 200V 25KA MODULE	4
B72210S1170K102 TDK EPCOS	VARISTOR 27V 500A DISC 10MM	2509
B72260B0751K001 TDK EPCOS	VARISTOR 1.2KV 70KA ENCASED DISC	132
V14E11P Wickmann / Littelfuse	VARISTOR 18V 4KA DISC 14MM	554900
ERZ-V10D560 Panasonic	VARISTOR 56V 1KA DISC 10MM	0
B72214P2421K104 TDK EPCOS	14MM, 420VAC, 10%, ADVANCED MP C	0
B72205S0200K101 TDK EPCOS	VARISTOR 33V 100A DISC 5MM	379
V10E510P Wickmann / Littelfuse	VARISTOR 820V 3.5KA DISC 10MM	5000
AMCV-1206H-300-T Abracon	VARISTOR 42V 250A 1206	0
EZJ-P0V270RM Panasonic	VARISTOR 27V 1A 0402	8627
B72214S0461K331 TDK EPCOS	VARISTOR 750V 4.5KA DISC 14MM	40
ERZ-E07A621 Panasonic	VARISTOR 620V 2.5KA DISC 9MM	3272
V82ZT4P Wickmann / Littelfuse	VARISTOR 82V 2.5KA DISC 10MM	0
V18MLA0805LNT Wickmann / Littelfuse	VARISTOR 25V 40A 0805	0
V251HC40 Wickmann / Littelfuse	VARISTOR 390V 40KA DISC 40MM	0
V25S385P Wickmann / Littelfuse	VARISTOR 620V 22KA RADIAL	1591
V9MLA0805LNH Wickmann / Littelfuse	VARISTOR 13.5V 40A 0805	796
ZV17K0603300NIR1 J.W. Miller / Bourns	VARISTOR SMD	3426
B72520E0200K062 TDK EPCOS	VARISTOR 33V 200A 1206	1638

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