TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
ZV20K0805121NIR1HT J.W. Miller / Bourns	ZV 20V 10% 0805 NI SN	3422
V14MLA1206NA Wickmann / Littelfuse	VARISTOR 18.1V 150A 1206	0
V14H130P Wickmann / Littelfuse	VARISTOR 5KA DISC 14MM	0
B72660M0131K072 TDK EPCOS	VARISTOR 205V 1.2KA 4032	1321
ERZ-E10A821 Panasonic	VARISTOR 820V 4.5KA DISC 12.50MM	1
V3.5MLA0603H Wickmann / Littelfuse	VARISTOR 3.5V 30A 0603	3435
V250LT20CP Wickmann / Littelfuse	VARISTOR 390V 6.5KA DISC 14MM	0
B72214S1300K102 TDK EPCOS	VARISTOR 47V 1KA DISC 14MM	210
V10E25P Wickmann / Littelfuse	VARISTOR 39V 2KA DISC 10MM	765
CGA0603MLA-19161E J.W. Miller / Bourns	VARISTOR 28V 20A 0603	0
820544211 Würth Elektronik Midcom	DISK VARISTOR STANDARD 14MM; 420	32
V14MLA0603NA Wickmann / Littelfuse	VARISTOR 18.7V 30A 0603	0
V10E300P Wickmann / Littelfuse	VARISTOR 470V 3.5KA DISC 10MM	19946
B72210U2351K501 TDK EPCOS	10MM, 350VAC, 10% ADVANCED, 125D	0
B72205S0141K111 TDK EPCOS	VARISTOR 220V 400A DISC 5MM	4500
ERZ-C32EK241 Panasonic	VARISTOR 240V 25KA MODULE	63
TMOV14RP175M Wickmann / Littelfuse	VARISTOR 270V 6KA DISC 14MM	0
V30MLA0603NA Wickmann / Littelfuse	VARISTOR 41.5V 30A 0603	0
ERZ-U22JP102B Panasonic	DELTATRANSIENT/SURGE ABSORBERS10	1
ERZ-E10B511CS Panasonic	VARISTOR 510V 4.5KA DISC 11.5MM	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