TVS - Varistors, MOVs

Part Number	Description / PDF	Quantity
ERZ-C20EK681Y Panasonic	VARISTOR 680V 8KA MODULE	18
B72220S0110K101 TDK EPCOS	VARISTOR 18V 2KA DISC 20MM	0
8S17SM300 Maida Development Company	MOV SURFACE MOUNT CHIP 3220 30VA	10000
ERZ-V14D911 Panasonic	VARISTOR 910V 5KA DISC 14MM	600
CGA0805MLA-18351E J.W. Miller / Bourns	VARISTOR 22.5V 120A 0805	0
PV115K4032R2 J.W. Miller / Bourns	PV SERIES 115V 4032 PKG	1000
RV471K14T Stackpole Electronics, Inc.	VARISTOR 470V 4.5KA DISC 14MM	0
TMOV34S681MPX2696 Wickmann / Littelfuse	VARISTOR 1.0875KV 40KA SQU 34MM	0
NTE1V095 NTE Electronics, Inc.	MOV 95V RMS	359
V5.5MLA020164NR Wickmann / Littelfuse	VARISTOR 11V 1A 0201	0
V25S320PX1347 Wickmann / Littelfuse	RAD VARISTOR 25MM	0
ERZ-C32EK361Y Panasonic	VARISTOR 360V 25KA MODULE	19
V10P17AUTO Wickmann / Littelfuse	VARISTOR 27V 1.5KA DISC 10MM	0
ERZ-V05D680 Panasonic	VARISTOR 68V 250A DISC 5MM	633
V575LA40CPX2855 Wickmann / Littelfuse	VARISTOR 910V 6.5KA DISC 14MM	0
CGA0805MLA-26221E J.W. Miller / Bourns	VARISTOR 33.5V 80A 0805	0
NTE2V030 NTE Electronics, Inc.	MOV 30V RMS	233
B72232B0231K001 TDK EPCOS	VARISTOR 360V 25KA ENCASED DISC	3
B72660M0301K072 TDK EPCOS	VARISTOR 470V 1.2KA 2SMD JLEAD	3448
TMOV34S391MP Wickmann / Littelfuse	VARISTOR 620V 40KA SQUARE 34MM	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