TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
V20P30PL1T7 Wickmann / Littelfuse	VARISTOR 47V 8KA DISC 20MM	0
V20E440P Wickmann / Littelfuse	VARISTOR 715V 10KA DISC 20MM	0
V230LT40CP Wickmann / Littelfuse	VARISTOR 360V 10KA DISC 20MM	0
V150ZA05P Wickmann / Littelfuse	VARISTOR 150V 400A DISC 5MM	0
V68ZT2P Wickmann / Littelfuse	VARISTOR 68V 250A DISC 7MM	0
TMOV20RP320M Wickmann / Littelfuse	VARISTOR 510V 10KA DISC 20MM	2005
TMOV34S301EP Wickmann / Littelfuse	VARISTOR 470V 40KA SQUARE 34MM	0
V275LU40CPX680 Wickmann / Littelfuse	VARISTOR 421V 10KA DISC 20MM	0
V5.5MLA1206H Wickmann / Littelfuse	VARISTOR 8.2V 150A 1206	959
TMOV14RP460E Wickmann / Littelfuse	VARISTOR 750V 6KA DISC 14MM	0
V275LA40AP Wickmann / Littelfuse	VARISTOR 430V 6.5KA DISC 20MM	2985
V68ZC2P Wickmann / Littelfuse	VARISTOR 68V 250A DISC 7MM	0
V36RA22 Wickmann / Littelfuse	VARISTOR 36V 2KA RADIAL BOX	0
V460LA20CP Wickmann / Littelfuse	VARISTOR 715V 6.5KA DISC 14MM	0
V36ZA80PX1347 Wickmann / Littelfuse	VARISTOR 36V 2KA DISC 20MM	0
V301DHB34 Wickmann / Littelfuse	VARISTOR 470V 40KA SQUARE 34MM	0
V625LA80CPX10 Wickmann / Littelfuse	VARISTOR 1KV 10KA DISC 20MM	0
V420SM7 Wickmann / Littelfuse	VARISTOR 679V 1.2KA 2SMD JLEAD	0
V07E420P Wickmann / Littelfuse	VARISTOR 680V 1.75KA DISC 7MM	0
V751BA60 Wickmann / Littelfuse	VARISTOR 1.2KV 70KA ENCASED DISC	24

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