TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
V3.5MLA0805NHAUTO Wickmann / Littelfuse	VARISTOR 5.35V 120A 0805	0
V14E14AUTO Wickmann / Littelfuse	VARISTOR 22V 3KA DISC 14MM	538
V120MA1A Wickmann / Littelfuse	VARISTOR 120V 100A SOD83A AXIAL	0
V250LU40CP Wickmann / Littelfuse	VARISTOR 390V 10KA DISC 20MM	0
SMOV34S511MP Wickmann / Littelfuse	VARISTOR 820V 40KA BOX 5 LEAD	0
V300LT2P Wickmann / Littelfuse	VARISTOR 490V 1.2KA DISC 7MM	0
V07E420PL1T5 Wickmann / Littelfuse	VARISTOR 680V 1.75KA DISC 7MM	0
V20P11P Wickmann / Littelfuse	VARISTOR 18V 8KA DISC 20MM	0
V680LA100BP Wickmann / Littelfuse	VARISTOR 1.06KV 6.5KA DISC 20MM	0
V150CH8T Wickmann / Littelfuse	VARISTOR 150V 250A 2SMD NO LEAD	2959
V275LA40CPX680 Wickmann / Littelfuse	VARISTOR 421V 10KA DISC 20MM	1490
FBMOV275M Wickmann / Littelfuse	VARISTOR 430V 40KA AXIAL CYLINDR	0
V150MT2B Wickmann / Littelfuse	VARISTOR 150V 100A SOD83A AXIAL	0
TMOV34S141EP Wickmann / Littelfuse	VARISTOR 220V 40KA SQUARE 34MM	0
V250LA20CP Wickmann / Littelfuse	VARISTOR 390V 6.5KA DISC 14MM	87
V151DB40 Wickmann / Littelfuse	VARISTOR 240V 40KA BLADE TYPE	19
V300LA40APX10 Wickmann / Littelfuse	VARISTOR 470V 6.5KA DISC 20MM	0
V47MT2A Wickmann / Littelfuse	VARISTOR 47V 40A SOD83A AXIAL	0
V175LU20CPX10 Wickmann / Littelfuse	VARISTOR 270V 10KA DISC 20MM	0
V20E20PL1B1 Wickmann / Littelfuse	VARISTOR 33V 8KA 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