TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
V320LS40CP Wickmann / Littelfuse	VARISTOR 510V 10KA DISC 20MM	0
DV175K3225R2 J.W. Miller / Bourns	DV SERIES 175V 3225 PKG SMD VARI	0
VDRS20W350BSE Vishay BC Components/Beyshlag/Draloric	VARISTOR 560V 6.5KA DISC 23MM	0
V751DHB34 Wickmann / Littelfuse	VARISTOR 1.2KV 40KA SQUARE 34MM	0
MOV-10D560K J.W. Miller / Bourns	VARISTOR 56V 500A DISC 10MM	2000
B72214P2141K102 TDK EPCOS	14MM, 140VAC, 10%, ADVANCED MP C	4882
TMOV25SP250M Wickmann / Littelfuse	VARISTOR 390V 20KA SQUARE 28MM	553
ERZ-E05A221 Panasonic	VARISTOR 220V 1.2KA DISC 7MM	321
B72530T0300K062 TDK EPCOS	VARISTOR 47V 300A 1210	192936
V660LS80CPX10 Wickmann / Littelfuse	VARISTOR 1.08KV 10KA DISC 20MM	0
ERZ-E10E681 Panasonic	VARISTOR 680V 4.5KA DISC 12.50MM	0
B72580T0131K072 TDK EPCOS	VARISTOR 205V 250A 1812	0
V150LS20AP Wickmann / Littelfuse	VARISTOR 240V 6.5KA DISC 20MM	0
ERZ-U11JP541 Panasonic	SINGLETRANSIENT/SURGE ABSORBERS1	1
RV271K10T Stackpole Electronics, Inc.	VARISTOR 270V 2.5KA DISC 10MM	0
B72214S0461K101 TDK EPCOS	VARISTOR 750V 4.5KA DISC 14MM	736
B72240B0751K001 TDK EPCOS	VARISTOR 1.2KV 40KA ENCASED DISC	18
102KD14 Yageo	MOV	0
MOV-07D121KTR J.W. Miller / Bourns	VARISTOR 120V 1.2KA DISC 7MM	531
270KD07 Yageo	MOV	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