TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
V25S550P Wickmann / Littelfuse	VARISTOR 910V 22KA RADIAL	0
TMOV20RP320EL2B7 Wickmann / Littelfuse	VARISTOR 510V 10KA DISC 20MM	0
ZV25K1210401NIR1HT J.W. Miller / Bourns	ZV 25V 10% 1210 NI SN	9828
B72520E0400K062 TDK EPCOS	VARISTOR 68V 100A 1206	2507
V275LC40AP Wickmann / Littelfuse	VARISTOR 430V 6.5KA DISC 20MM	0
ERZ-V14D221 Panasonic	VARISTOR 220V 6KA DISC 14MM	7984
V150LT20CPX2855 Wickmann / Littelfuse	VARISTOR 240V 10KA DISC 20MM	0
B72214P2171K101 TDK EPCOS	VARISTOR 270V 6KA DISC 14MM	0
VCAS080505A150RP Elco (AVX)	TRANSGUARD	8000
V20P320P Wickmann / Littelfuse	VARISTOR 510V 10KA DISC 20MM	0
V275LC40BP Wickmann / Littelfuse	VARISTOR 421V 6.5KA DISC 20MM	0
V07E60P Wickmann / Littelfuse	VARISTOR 100V 1.75KA DISC 7MM	6000
B72210P2421K101 TDK EPCOS	VARISTOR 680V 3.5KA DISC 10MM	231
VC1210K401R011 KEMET	VARISTOR 33V 400A 1210	0
CG0603MLE-18E J.W. Miller / Bourns	VARISTOR 0603	1207
B72210S0250K151 TDK EPCOS	VARISTOR 39V 500A DISC 10MM	1481
V130LU20APX10 Wickmann / Littelfuse	VARISTOR 205V 6.5KA DISC 20MM	0
CG0603MLA-18KE J.W. Miller / Bourns	VARISTOR 22V 30A 0603	1993145
MVR20D391K Meritek	VARISTOR 390V 6500A 20MM DISC TH	0
V550LA80CP Wickmann / Littelfuse	VARISTOR 880V 10KA DISC 20MM	6238

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