TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
V420LT40CPX2855 Wickmann / Littelfuse	VARISTOR 680V 10KA DISC 20MM	0
B72220S0200K131 TDK EPCOS	VARISTOR 33V 2KA DISC 20MM	4374
V18ZC05P Wickmann / Littelfuse	VARISTOR 18V 100A DISC 5MM	0
B72650M0170K072 TDK EPCOS	VARISTOR 27V 100A 3225	1654
B72220S1300K102 TDK EPCOS	VARISTOR 47V 2KA DISC 20MM	899
V250LA40CPX2855 Wickmann / Littelfuse	VARISTOR 390V 10KA DISC 20MM	0
AV20K1206201NIR1HT J.W. Miller / Bourns	VARISTOR	2498
MVR14D820K-S Meritek	VARISTOR 82V 6000A DISC 14MM HIG	0
V390CH8T Wickmann / Littelfuse	VARISTOR 390V 250A 2SMD NO LEAD	0
MVR05D101K Meritek	VARISTOR 100V 400A 5MM DISC THRU	0
B72207S0131K111 TDK EPCOS	VARISTOR 205V 1.2KA DISC 7MM	2295
MOVS2825V040 PowerStor (Eaton)	VARISTOR SMD 2825 40V	0
MOV-20D102K J.W. Miller / Bourns	VARISTOR 1KV 6.5KA DISC 20MM	0
MOVS2825V140 PowerStor (Eaton)	VARISTOR SMD 2825 140V	0
MOV-10D391KTR J.W. Miller / Bourns	VARISTOR 390V 2.5KA DISC 10MM	42
ZV50K1812401NIR1 J.W. Miller / Bourns	VARISTOR SMD	986
B72590D0150A060 TDK EPCOS	VARISTOR 20V 10A 0402	33666
ERZ-E10A621 Panasonic	VARISTOR 620V 4.5KA DISC 12.50MM	0
V22ZA2P Wickmann / Littelfuse	VARISTOR 22V 500A DISC 10MM	0
AMCV-1812H-220-T Abracon	VARISTOR 30V 800A 1812	10619

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