TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
ERZ-U26JP132F Panasonic	SINGLETRANSIENT/SURGE ABSORBERS1	1
ERZ-V20D470 Panasonic	VARISTOR 47V 3KA DISC 20MM	1957
ERZ-E10F112 Panasonic	VARISTOR 1.1KV 4.5KA DISC	0
ERZ-V10D391 Panasonic	VARISTOR 390V 3.5KA DISC 10MM	0
ERZ-E10A471 Panasonic	VARISTOR 470V 4.5KA DISC 11.5MM	76
ERZ-C32EK391 Panasonic	VARISTOR 390V 25KA MODULE	140
ERZ-E10E241 Panasonic	VARISTOR 240V 4.5KA DISC 11.5MM	0
ERZ-E05A431 Panasonic	VARISTOR 430V 1.2KA DISC 7MM	7
ERZ-V20D241 Panasonic	VARISTOR 240V 10KA DISC 20MM	1763
EZJ-S1VC392 Panasonic	VARISTOR 30V 0603	6552
ERZ-E10A391 Panasonic	VARISTOR 390V 4.5KA DISC 11.5MM	985
ERZ-V10D221 Panasonic	VARISTOR 220V 3.5KA DISC 10MM	142
ERZ-E05A471CS Panasonic	VARISTOR 470V 1.2KA DISC 7MM	0
ERZ-VF2M391 Panasonic	VARISTOR 390V 300A 2SMD JLEAD	332
ERZ-C20EK241 Panasonic	VARISTOR 240V 8KA MODULE	35
ERZ-C20EK471Y Panasonic	VARISTOR 470V 8KA MODULE	2
ERZ-V20D390 Panasonic	VARISTOR 39V 3KA DISC 20MM	0
ERZ-E05A271CS Panasonic	VARISTOR 270V 1.2KA DISC 7MM	0
EZJ-S1VD182 Panasonic	VARISTOR 50V 0603	30064
ERZ-V07D180 Panasonic	VARISTOR 18V 500A DISC 7MM	3045

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