TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
B72650M0301K072 TDK EPCOS	VARISTOR 470V 400A 2SMD JLEAD	332
V05P25AUTOL1A Wickmann / Littelfuse	VARISTOR 39V 400A DISC 5MM	0
V14H300P Wickmann / Littelfuse	VARISTOR 470V 6.5KA DISC 14MM	0
VE0805L121R008 KEMET	VARISTOR 15V 120A 0805	0
ZV95K1812T301N Stackpole Electronics, Inc.	VARISTOR 150V 300A 1812	0
CGA0402MLC-24G J.W. Miller / Bourns	VARISTOR 0402	44423
ERZ-E10B391CS Panasonic	VARISTOR 390V 4.5KA DISC 11.5MM	0
ERZ-E11A102CS Panasonic	VARISTOR 1KV 5KA DISC 13MM	0
VDRS05C150BSE Vishay BC Components/Beyshlag/Draloric	VARISTOR 240V 400A DISC 7MM	0
MVR14D121K Meritek	VARISTOR 120V 4500A 14MM DISC TH	2000
TMOV14RP420E Wickmann / Littelfuse	VARISTOR 680V 6KA DISC 14MM	0
VAR-18080115M3P-XK TDK Corporation	VARISTOR 11.5V RING SURFACE ELEC	0
820475001 Würth Elektronik Midcom	DISK VARISTOR HIGHSURGE 7MM; 50V	0
V175LC20CPX10 Wickmann / Littelfuse	VARISTOR 270V 10KA DISC 20MM	0
ERZ-C20EK102Y Panasonic	VARISTOR 1KV 8KA MODULE	0
B72660M0231K072 TDK EPCOS	VARISTOR 1.2KA 2SMD JLEAD	2556
MVR07D301K-S Meritek	VARISTOR 300V 1750A DISC 7MM HIG	0
V22CH8S Wickmann / Littelfuse	VARISTOR 22V 100A 2SMD NO LEAD	0
AMCV-1210H-650-T Abracon	VARISTOR 82V 300A 1210	0
V33ZS20P Wickmann / Littelfuse	VARISTOR 33V 2KA DISC 20MM	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