TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
V8ZT05P Wickmann / Littelfuse	VARISTOR 8.5V 50A DISC 5MM	0
MVR05D431K-S Meritek	VARISTOR 430V 800A DISC 5MM HIGH	0
TMOV20RP550E Wickmann / Littelfuse	VARISTOR 910V 10KA DISC 20MM	31991200
2839130 Phoenix Contact	VARISTOR MODULE	7
MOV-20D391KTR J.W. Miller / Bourns	VARISTOR 390V 6.5KA DISC 20MM	0
V25S130P Wickmann / Littelfuse	VARISTOR 205V 22KA RADIAL	700
EZJ-P0V120JA Panasonic	VARISTOR 12V 220PF 0402	9122
MOV-10D270KTR J.W. Miller / Bourns	VARISTOR 27V 500A DISC 10MM	0
ERZ-V14D470 Panasonic	VARISTOR 47V 2KA DISC 14MM	0
VE1812K601R035 KEMET	VARISTOR 56V 600A 1812	0
SMOV25S421NP Wickmann / Littelfuse	VARISTOR 680V 20KA BOX 5 LEAD	0
V14P25P Wickmann / Littelfuse	VARISTOR 39V 4KA DISC 14MM	0
B72510E0300K062 TDK EPCOS	VARISTOR 47V 80A 0805	6663
VDRUS10T230BKE Vishay BC Components/Beyshlag/Draloric	VDR US 10D 4500A 230V KNLDS	0
B72530T0080L062 TDK EPCOS	VARISTOR 15V 400A 1210	0
ERZ-C20EK391 Panasonic	VARISTOR 390V 8KA MODULE	0
V385LC10P Wickmann / Littelfuse	VARISTOR 620V 2.5KA DISC 10MM	0
V2AF114A300Y2EDP Elco (AVX)	VARISTOR 18.5V 30A 0805	1000
B72205S0350K101 TDK EPCOS	VARISTOR 56V 100A DISC 5MM	1643
V14MLA0805LNH Wickmann / Littelfuse	VARISTOR 18.1V 40A 0805	79

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