TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
FBMOV250M Wickmann / Littelfuse	VARISTOR 390V 40KA AXIAL CYLINDR	0
V14MLA0805LH Wickmann / Littelfuse	VARISTOR 18.1V 40A 0805	464
V150LC20CP Wickmann / Littelfuse	VARISTOR 240V 10KA DISC 20MM	0
V430CH8S Wickmann / Littelfuse	VARISTOR 430V 250A 2SMD NO LEAD	0
V300LT40CPX2855 Wickmann / Littelfuse	VARISTOR 470V 10KA DISC 20MM	0
V25S140P Wickmann / Littelfuse	VARISTOR 220V 22KA RADIAL	125
V300LS2P Wickmann / Littelfuse	VARISTOR 490V 1.2KA DISC 7MM	0
V14E20P Wickmann / Littelfuse	VARISTOR 33V 4KA DISC 14MM	700
V660LT80CPX2855 Wickmann / Littelfuse	VARISTOR 1.08KV 10KA DISC 20MM	0
V510LC40AP Wickmann / Littelfuse	VARISTOR 820V 4.5KA DISC 14MM	0
V275LS10CP Wickmann / Littelfuse	VARISTOR 430V 3.5KA DISC 10MM	0
FBMOV150M Wickmann / Littelfuse	VARISTOR 240V 40KA AXIAL CYLINDR	0
V07P420P Wickmann / Littelfuse	VARISTOR 680V 1.75KA DISC 7MM	0
V05P17AUTO Wickmann / Littelfuse	VARISTOR 27V 400A DISC 5MM	0
V430ZS05P Wickmann / Littelfuse	VARISTOR 430V 400A DISC 5MM	0
V27CH8S Wickmann / Littelfuse	VARISTOR 27V 100A 2SMD NO LEAD	0
V751HB34 Wickmann / Littelfuse	VARISTOR 1.2KV 40KA SQUARE 34MM	0
V36ZS80PX10 Wickmann / Littelfuse	VARISTOR 36V 2KA DISC 20MM	0
TMOV34S351MP Wickmann / Littelfuse	VARISTOR 560V 40KA SQUARE 34MM	0
V275LT10CP Wickmann / Littelfuse	VARISTOR 430V 3.5KA 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