TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
V271DB40 Wickmann / Littelfuse	VARISTOR 430V 40KA BLADE TYPE	0
TMOV25SP130M Wickmann / Littelfuse	VARISTOR 205V 20KA SQUARE 28MM	0
V230LA40AP Wickmann / Littelfuse	VARISTOR 360V 6.5KA DISC 20MM	26213500
V175LC20CPX2855 Wickmann / Littelfuse	VARISTOR 270V 10KA DISC 20MM	0
V20P14AUTO Wickmann / Littelfuse	VARISTOR 22V 5KA DISC 20MM	0
V575LS40CPX2855 Wickmann / Littelfuse	VARISTOR 910V 6.5KA DISC 14MM	0
V130LA20APX2855 Wickmann / Littelfuse	VARISTOR 205V 6.5KA DISC 20MM	0
V275LU40CP Wickmann / Littelfuse	VARISTOR 430V 10KA DISC 20MM	0
V175LT20CPX425 Wickmann / Littelfuse	VARISTOR 266V 10KA DISC 20MM	0
TMOV20RP175M Wickmann / Littelfuse	VARISTOR 270V 10KA DISC 20MM	586
V480LA40APX2855 Wickmann / Littelfuse	VARISTOR 750V 4.5KA DISC 14MM	0
V20P25P Wickmann / Littelfuse	VARISTOR 39V 8KA DISC 20MM	0
TMOV20RP420M Wickmann / Littelfuse	VARISTOR 680V 10KA DISC 20MM	945
V68MLA1206NT Wickmann / Littelfuse	VARISTOR 83V 180A 1206	0
V27MT1B Wickmann / Littelfuse	VARISTOR 27V 40A SOD83A AXIAL	0
V351HA40 Wickmann / Littelfuse	VARISTOR 549.5V 40KA DISC 40MM	0
V175LS20CPX425 Wickmann / Littelfuse	VARISTOR 266V 10KA DISC 20MM	0
V150LS20CPX2855 Wickmann / Littelfuse	VARISTOR 240V 10KA DISC 20MM	0
V130LA20BP Wickmann / Littelfuse	VARISTOR 205V 6.5KA DISC 20MM	75
V33ZS2PX2855 Wickmann / Littelfuse	VARISTOR 33V 500A DISC 10MM	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