TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
V10E275P Wickmann / Littelfuse	VARISTOR 430V 3.5KA DISC 10MM	1226
VC1812K401R060 KEMET	VARISTOR 100V 400A 1812	5813
B72210S0950K151 TDK EPCOS	VARISTOR 150V 2.5KA DISC 10MM	0
TMOV34S331EP Wickmann / Littelfuse	VARISTOR 528.5V 40KA SQUARE 34MM	0
V250LA4P Wickmann / Littelfuse	VARISTOR 390V 1.2KA DISC 7MM	2512
CGA1206MLA-22841E J.W. Miller / Bourns	VARISTOR 27V 100A 1206	0
V20P17P Wickmann / Littelfuse	VARISTOR 27V 8KA DISC 20MM	0
V420LA7PX2855 Wickmann / Littelfuse	VARISTOR 680V 1.2KA DISC 7MM	0
ERZ-V14D361 Panasonic	VARISTOR 360V 6KA DISC 14MM	335
MOV-20D270K J.W. Miller / Bourns	VARISTOR 27V 2KA DISC 20MM	0
B72500E2170K060 TDK EPCOS	VARISTOR 27V 10A 0603	11276
AMCV-1812H-260-T Abracon	VARISTOR 35V 800A 1812	0
ZV30K2220T122N Stackpole Electronics, Inc.	VARISTOR 47V 12KA 2220	15704000
V20E175P Wickmann / Littelfuse	VARISTOR 270V 10KA DISC 20MM	153
820415511B Würth Elektronik Midcom	DISK VARISTOR HIGHSURGE WE-VD -	0
ERZ-E07A271CS Panasonic	VARISTOR 270V 2.5KA DISC 9MM	0
B72220S0151K551 TDK EPCOS	VARISTOR 240V 8KA DISC 20MM	0
B72207S0500K111 TDK EPCOS	VARISTOR 82V 1.2KA DISC 7MM	2008
MG064L18X500TP Elco (AVX)	VARISTOR 28V 20A 0612	0
820513811 Würth Elektronik Midcom	DISK VARISTOR STANDARD 10MM; 385	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