TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
V130LU10A	RADIAL LEAD VARISTOR	500
MLVB06V18C0R5 PowerStor (Eaton)	VARISTOR 105V 0603	0
VGAS120616N390DP Elco (AVX)	VARISTOR 24.5V 200A 1206	0
B72220R2301K101 TDK EPCOS	VARISTOR 470V 10KA DISC 23MM	141
MVR20D270K-S Meritek	VARISTOR 27V 3000A DISC 20MM HIG	0
B72207S0400K101 TDK EPCOS	VARISTOR 68V 250A DISC 7MM	1994
VDRS14T420BSE Vishay BC Components/Beyshlag/Draloric	VARISTOR 680V 4.5KA DISC 16.5MM	0
SV150K5BL1 J.W. Miller / Bourns	SV 150VRMS 5MM BULK L1	0
ERZ-U24JP192F Panasonic	SINGLETRANSIENT/SURGE ABSORBERS1	1
V660LA10CP Wickmann / Littelfuse	VARISTOR 1.08KV 3.5KA DISC 10MM	0
V22ZC1P Wickmann / Littelfuse	VARISTOR 22V 250A DISC 7MM	0
V511HA40 Wickmann / Littelfuse	VARISTOR 820V 40KA DISC 40MM	0
V5.5MLA1206NH Wickmann / Littelfuse	VARISTOR 8.2V 150A 1206	0
V300LS40CPX745 Wickmann / Littelfuse	VARISTOR 455V 10KA DISC 20MM	0
681KD20 Yageo	MOV	0
B72520V0300K062 TDK EPCOS	VARISTOR 47V 200A 1206	0
V14E75P Wickmann / Littelfuse	VARISTOR 120V 6.5KA DISC 14MM	3595
EZJ-P1V270EM Panasonic	VARISTOR 27V 5A 0603	3484
V18MLA0805LNA Wickmann / Littelfuse	VARISTOR 25V 40A 0805	0
MOV-10D820K J.W. Miller / Bourns	VARISTOR 82V 2.5KA DISC 10MM	57

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