TVS - Varistors, MOVs

Image	Part Number	Description / PDF	Quantity	Rfq
	ERZ-E07E471 Panasonic	VARISTOR 470V 2.5KA DISC 9MM	0
	ERZ-E05E391 Panasonic	VARISTOR 390V 1.2KA DISC 7MM	0
	ERZ-E07E621 Panasonic	VARISTOR 620V 2.5KA DISC 10MM	0
	ERZ-E11B391CS Panasonic	VARISTOR 390V 6KA DISC 13MM	0
	ERZ-E08F681 Panasonic	VARISTOR 680V 3.5KA DISC 11.5MM	0
	ERZ-E07B361CS Panasonic	VARISTOR 360V 2.5KA DISC 9MM	0
	ERZ-E11E431 Panasonic	VARISTOR 430V 6KA DISC 13MM	0
	ERZ-E07F361 Panasonic	VARISTOR 360V 2.5KA DISC 9MM	0
	ERZ-E07E241 Panasonic	VARISTOR 240V 2.5KA DISC 9MM	0
	ERZ-E08E361 Panasonic	VARISTOR 360V 3.5KA DISC 10.5MM	0
	ERZ-E05B391CS Panasonic	VARISTOR 390V 1.2KA DISC 7MM	0
	ERZ-E14A821SC Panasonic	VARISTOR DISC 14MM 820V	0
	ERZ-E14A102SC Panasonic	VARISTOR DISC 14MM 1000V	0
	ERZ-E07E201 Panasonic	VARISTOR 200V 2.5KA DISC 9MM	0
	ERZ-E07E331 Panasonic	VARISTOR 330V 2.5KA DISC 9MM	0
	ERZ-E05B331CS Panasonic	VARISTOR 330V 1.2KA DISC 7MM	0
	ERZ-E05B431CS Panasonic	VARISTOR 430V 1.2KA DISC 7MM	0
	ERZ-E11F112 Panasonic	VARISTOR 1.1KV 5KA DISC 14MM	0
	ERZ-E08E471 Panasonic	VARISTOR 470V 3.5KA DISC 10.5MM	0
	ERZ-E07B561CS Panasonic	VARISTOR 560V 2.5KA DISC 9MM	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