TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
V300LA4P Wickmann / Littelfuse	VARISTOR 470V 1.2KA DISC 7MM	148
V300LS10P Wickmann / Littelfuse	VARISTOR 470V 2.5KA DISC 10MM	27361
V391HB34 Wickmann / Littelfuse	VARISTOR 604V 40KA SQUARE 34MM	0
V5.5MLA1206NA Wickmann / Littelfuse	VARISTOR 8.2V 150A 1206	0
V05E25AUTO Wickmann / Littelfuse	VARISTOR 39V 400A DISC 5MM	0
V14E25P Wickmann / Littelfuse	VARISTOR 39V 4KA DISC 14MM	1021
V321HB34 Wickmann / Littelfuse	VARISTOR 510V 40KA SQUARE 34MM	27
TMOV14RP150M Wickmann / Littelfuse	VARISTOR 240V 6KA DISC 14MM	0
V321HC40 Wickmann / Littelfuse	VARISTOR 510V 40KA DISC 40MM	0
V230LU20CPX2855 Wickmann / Littelfuse	VARISTOR 360V 6.5KA DISC 14MM	0
V10P95P Wickmann / Littelfuse	VARISTOR 150V 3.5KA DISC 10MM	0
V07E25P Wickmann / Littelfuse	VARISTOR 39V 1KA DISC 7MM	1500
V250LU10CPX2855 Wickmann / Littelfuse	VARISTOR 390V 3.5KA DISC 10MM	0
V130LS1P Wickmann / Littelfuse	VARISTOR 220V 1.2KA DISC 7MM	0
V47ZA20P Wickmann / Littelfuse	VARISTOR 47V 2KA DISC 20MM	4490
V321HA40 Wickmann / Littelfuse	VARISTOR 510V 40KA DISC 40MM	0
V3.5MLA1206NH Wickmann / Littelfuse	VARISTOR 5.35V 100A 1206	2490
V36ZT80P Wickmann / Littelfuse	VARISTOR 36V 2KA DISC 20MM	0
V07P17AUTO Wickmann / Littelfuse	VARISTOR 27V 800A DISC 7MM	0
V510SM7 Wickmann / Littelfuse	VARISTOR 822.5V 1.2KA 2SMD	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