TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
MVR05D820K Meritek	VARISTOR 82V 400A 5MM DISC THRU	1000
MVR20D221K Meritek	VARISTOR 220V 6500A 20MM DISC TH	0
MVR14D820K Meritek	VARISTOR 82V 4500A 14MM DISC THR	1000
MVR05D560K Meritek	VARISTOR 56V 100A 5MM DISC THRU	0
MVR14D621K Meritek	VARISTOR 620V 4500A 14MM DISC TH	0
MVR20D201K Meritek	VARISTOR 200V 6500A 20MM DISC TH	2750
MVR14D270K Meritek	VARISTOR 27V 1KA 14MM DISC THRU	0
MVR20D180K Meritek	VARISTOR 18V 2KA 20MM DISC THRU	1000
MVR14D181K Meritek	VARISTOR 180V 4500A 14MM DISC TH	0
MVR20D220K-S Meritek	VARISTOR 22V 3000A DISC 20MM HIG	0
MVR14D511K Meritek	VARISTOR 510V 4500A 14MM DISC TH	1750
MVR05D680K-S Meritek	VARISTOR 68V 250A DISC 5MM HIGH	0
MVR20D431K Meritek	VARISTOR 430V 6500A 20MM DISC TH	0
MVR07D301K Meritek	VARISTOR 300V 1200A 7MM DISC THR	0
MVR10D102K Meritek	VARISTOR 1000V 2500A 10MM DISC T	0
MVR20D820K-S Meritek	VARISTOR 82V 10000A DISC 20MM HI	0
MVR10D241K-S Meritek	VARISTOR 240V 3500A DISC 10MM HI	1000
MVR10D560K-S Meritek	VARISTOR 56V 1000A DISC 10MM HIG	0
MVR07D511K-S Meritek	VARISTOR 510V 1750A DISC 7MM HIG	0
MVR14D241K-S Meritek	VARISTOR 240V 6000A DISC 14MM HI	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