TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
V68ZS3P Wickmann / Littelfuse	VARISTOR 68V 500A DISC 10MM	0
V275LT40BP Wickmann / Littelfuse	VARISTOR 421V 6.5KA DISC 20MM	1999
V131DHB34 Wickmann / Littelfuse	VARISTOR 205V 40KA SQUARE 34MM	0
V39ZT1PX2855 Wickmann / Littelfuse	VARISTOR 39V 250A DISC 7MM	0
V320LT20AP Wickmann / Littelfuse	VARISTOR 510V 4.5KA DISC 14MM	3185
TMOV25SP625M Wickmann / Littelfuse	VARISTOR 1KV 20KA SQUARE 28MM	0
V385LC20CPX2855 Wickmann / Littelfuse	VARISTOR 620V 6.5KA DISC 14MM	0
V18AUMLA1206NH Wickmann / Littelfuse	VARISTOR 27.5V 1206	4742
FBMOV550M Wickmann / Littelfuse	VARISTOR 910V 40KA AXIAL CYLINDR	0
V175LA10CPX2855 Wickmann / Littelfuse	VARISTOR 270V 6.5KA DISC 14MM	0
V300LC40CP Wickmann / Littelfuse	VARISTOR 470V 10KA DISC 20MM	0
V510LC80BP Wickmann / Littelfuse	VARISTOR 799V 6.5KA DISC 20MM	0
V14E25AUTO Wickmann / Littelfuse	VARISTOR 39V 3KA DISC 14MM	0
TMOV14RP140M Wickmann / Littelfuse	VARISTOR 220V 6KA DISC 14MM	0
SMOV34S511NP Wickmann / Littelfuse	VARISTOR 820V 40KA BOX 5 LEAD	0
V230LC20CPX2855 Wickmann / Littelfuse	VARISTOR 360V 6.5KA DISC 14MM	0
V18ZS40P Wickmann / Littelfuse	VARISTOR 18V 2KA DISC 20MM	0
V420LS20CP Wickmann / Littelfuse	VARISTOR 680V 6.5KA DISC 14MM	0
V18MLN41206WT Wickmann / Littelfuse	VARISTOR 25V 30A 1206	119965
V275LT40CP Wickmann / Littelfuse	VARISTOR 430V 10KA 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