Passive Components Blog
No Result
View All Result
  • Home
  • NewsFilter
    • All
    • Aerospace & Defence
    • Antenna
    • Applications
    • Automotive
    • Capacitors
    • Circuit Protection Devices
    • electro-mechanical news
    • Filters
    • Fuses
    • Inductors
    • Industrial
    • Integrated Passives
    • inter-connect news
    • Market & Supply Chain
    • Market Insights
    • Medical
    • Modelling and Simulation
    • New Materials & Supply
    • New Technologies
    • Non-linear Passives
    • Oscillators
    • Passive Sensors News
    • Resistors
    • RF & Microwave
    • Telecommunication
    • Weekly Digest

    TDK Introduces High Current 80VDC Board-Mount EMI Filters

    Bourns Releases High Heat Tolerant TO-227 Thick Film Resistor

    TDK Increases Current Ratings of Automotive Thin-Film Power Inductors

    Sumida Announces New DC Common Mode Choke Coil Series

    KYOCERA AVX Releases New 3dB Hybrid Couplers

    SCHURTER Unveils High Voltage Fuses for EV Applications

    YAGEO Releases First to Market 750V Aluminum Capacitors

    binder Introduces M9 Compact Circular Connector

    Smolteks CNF-MIM Capacitors Meet Thermal and Voltage Stability Industry Requirements

    Trending Tags

    • Ripple Current
    • RF
    • Leakage Current
    • Tantalum vs Ceramic
    • Snubber
    • Low ESR
    • Feedthrough
    • Derating
    • Dielectric Constant
    • New Products
    • Market Reports
  • VideoFilter
    • All
    • Antenna videos
    • Capacitor videos
    • Circuit Protection Video
    • Filter videos
    • Fuse videos
    • Inductor videos
    • Inter-Connect Video
    • Non-linear passives videos
    • Oscillator videos
    • Passive sensors videos
    • Resistor videos

    Accelerating Full Bridge LLC Resonant Converter Design with Frenetic AI

    Understanding Switched Capacitor Converters

    Coupled Inductors Circuit Model and Examples of its Applications

    Inductor Resonances and its Impact to EMI

    Highly Reliable Flex Rigid PCBs, Würth Elektronik Webinar

    Causes of Oscillations in Flyback Converters

    How to design a 60W Flyback Transformer

    Modeling and Simulation of Leakage Inductance

    Power Inductor Considerations for AI High Power Computing – Vishay Video

    Trending Tags

    • Capacitors explained
    • Inductors explained
    • Resistors explained
    • Filters explained
    • Application Video Guidelines
    • EMC
    • New Products
    • Ripple Current
    • Simulation
    • Tantalum vs Ceramic
  • Knowledge Blog
  • Suppliers
    • Who is Who
  • Events
  • Home
  • NewsFilter
    • All
    • Aerospace & Defence
    • Antenna
    • Applications
    • Automotive
    • Capacitors
    • Circuit Protection Devices
    • electro-mechanical news
    • Filters
    • Fuses
    • Inductors
    • Industrial
    • Integrated Passives
    • inter-connect news
    • Market & Supply Chain
    • Market Insights
    • Medical
    • Modelling and Simulation
    • New Materials & Supply
    • New Technologies
    • Non-linear Passives
    • Oscillators
    • Passive Sensors News
    • Resistors
    • RF & Microwave
    • Telecommunication
    • Weekly Digest

    TDK Introduces High Current 80VDC Board-Mount EMI Filters

    Bourns Releases High Heat Tolerant TO-227 Thick Film Resistor

    TDK Increases Current Ratings of Automotive Thin-Film Power Inductors

    Sumida Announces New DC Common Mode Choke Coil Series

    KYOCERA AVX Releases New 3dB Hybrid Couplers

    SCHURTER Unveils High Voltage Fuses for EV Applications

    YAGEO Releases First to Market 750V Aluminum Capacitors

    binder Introduces M9 Compact Circular Connector

    Smolteks CNF-MIM Capacitors Meet Thermal and Voltage Stability Industry Requirements

    Trending Tags

    • Ripple Current
    • RF
    • Leakage Current
    • Tantalum vs Ceramic
    • Snubber
    • Low ESR
    • Feedthrough
    • Derating
    • Dielectric Constant
    • New Products
    • Market Reports
  • VideoFilter
    • All
    • Antenna videos
    • Capacitor videos
    • Circuit Protection Video
    • Filter videos
    • Fuse videos
    • Inductor videos
    • Inter-Connect Video
    • Non-linear passives videos
    • Oscillator videos
    • Passive sensors videos
    • Resistor videos

    Accelerating Full Bridge LLC Resonant Converter Design with Frenetic AI

    Understanding Switched Capacitor Converters

    Coupled Inductors Circuit Model and Examples of its Applications

    Inductor Resonances and its Impact to EMI

    Highly Reliable Flex Rigid PCBs, Würth Elektronik Webinar

    Causes of Oscillations in Flyback Converters

    How to design a 60W Flyback Transformer

    Modeling and Simulation of Leakage Inductance

    Power Inductor Considerations for AI High Power Computing – Vishay Video

    Trending Tags

    • Capacitors explained
    • Inductors explained
    • Resistors explained
    • Filters explained
    • Application Video Guidelines
    • EMC
    • New Products
    • Ripple Current
    • Simulation
    • Tantalum vs Ceramic
  • Knowledge Blog
  • Suppliers
    • Who is Who
  • Events
No Result
View All Result
Passive Components Blog
No Result
View All Result

Multilayer varistors in automotive circuit protection

16.12.2019
Reading Time: 7 mins read
A A

Electronics 360 with AVX Corporation published an article on overview of multilayer varistors and its use in automotive circuit protection applications.

Transient voltage suppression (TVS) based on multilayer varistors (MLVs) is designed to prevent damage to sensitive devices and circuits from voltage spikes. The damage to sensors, circuits and electronic components can disable critical functions, rendering a vehicle inoperable until repairs are made.

RelatedPosts

TDK Introduces High Current 80VDC Board-Mount EMI Filters

Bourns Releases High Heat Tolerant TO-227 Thick Film Resistor

TDK Increases Current Ratings of Automotive Thin-Film Power Inductors

Figure 1. MLVs activate and redirect damaging voltage spikes. Source: AVX

Figure 1. MLVs activate and redirect damaging voltage spikes. Source: AVX

Sources of damaging voltage spikes can include electrostatic discharges (ESD, or static shock), induced secondary voltage from lightning strikes (a high voltage ESD), electromagnetic pulses, voltage surge from motor switching, jump starts, energizing solenoid coil actuators, arcing from faults and load dump from alternator switching. When an electrical circuit or system experiences damaging voltage spikes, a normally off MLV is activated and protects the device by redirecting the spike to ground.

MLVs are constructed from fine, uniform grain ceramic doped with semiconducting zinc oxide (ZnO), which creates a Schottky barrier response. The varistors are fabricated by surrounding ZnO grains with very thin electrically insulating ceramic layers in a sintering process. The insulating ceramic used is a temperature stable X7R-like dielectric, which provides a wide operating temperature range and good capacitance stability. A very uniform and fine grain size has a significant impact on maintaining the high performance of AVX’s MLVs.

Figure 2. Construction and cross section of an AVX MLV. Source: AVX

Figure 2. Construction and cross section of an AVX MLV. Source: AVX

While lower cost MLVs may claim to meet the same standards, their lower quality of manufacture results in devices with coarse structures and therefore poor reliability and performance. After repeated voltage strikes with high-current pulses, older or lower quality varistors degrade in electrical performance resulting in decreased breakdown voltage and increased leakage current. The irregular intergranular boundaries in lower quality MLVs cause restricted current paths and other non-Schottky barrier paralleled conduction paths in the ceramic.

TVS diodes are an alternative to MLVs. TVS diodes are open junction semiconductor devices that appear as an opening in the circuit during normal operation. During a voltage spike, the TVS diode junction avalanches, shunting the transient current to ground. TVS diodes have fast response times, but they cannot match the repeated strike capability of MLVs.

Automotive trends and circuit protection requirements

Today’s gas or diesel internal combustion engine (ICE) vehicles continue to employ assorted electronics for safety, self-driving, assisted driving, cameras, engine performance optimization with engine control unit (ECU), communications and navigation. Many of the advanced driver assistance systems (ADASs) in current automobiles have multiple processors as well as high-current sensors and actuators. ICEs already contain over 40 motors and actuators to drive windows, doors, seats, pumps, windshield wipers and other components.

Figure 3. An ICE vehicle. Source: U.S. Department of Transportation

Figure 3. An ICE vehicle. Source: U.S. Department of Transportation

Automotive OEMs are moving away from combustion technology and toward electrification to improve performance as well as reduce emissions and improve fuel efficiency to meet regulations. There have been initial reports of some OEMs moving away from the development of ICE vehicles in the near future. In addition, many electric vehicle (EV) startups have entered or are entering the EV market such as Tesla, Bollinger, Rivian and Workhorse.

EVs have additional electrical power systems controlled by electronics requiring transient voltage spike protection at higher voltage levels. For instance, many of the plug-in EV electrical systems use high voltage(e.g., 400 V) battery systems and hybrid EVs use 48 V systems because the high voltage boosts efficiency and allows lower currents for the same wattage. With lower I2R, the diameter and weight of power cables can be reduced. DC-DC converters are used to produce 12 V power for electronics, sensors, displays and actuators. Future EVs and ICE vehicles may power electronics with a 48 V system to further increase efficiency. Since electrical vehicle batteries must be recharged periodically, the high-voltage chargers can introduce an electric shock hazard (i.e., “hot skin”) and possible source of voltage spikes, especially in cases with incorrect ground bonding (see “Electric Safety of Plug-In Electric Vehicles”). Future vehicles will require TVS devices capable of protection at higher voltage levels without increases in size and weight.

Figure 4. An EV. Source: U.S. Department of Energy
Figure 4. An EV. Source: U.S. Department of Energy

Electronics are often exposed to elevated temperatures from the environment due to vehicle compactness and proximity to the combustion engine, electric motor, Li-ion battery, transmission and brakes. High-speed data lines, RF circuits, antennas, capacitive sensors, touch controls and other capacitance sensitive applications require low signal distortion, low loss and low capacitance TVS devices. Automotive electronics devices also require electromagnetic inference (EMI) filtering. TVS devices can be designed to provide bi-directional transient voltage protection in the on-state and EMI/RFI filtering in the off-state. TVS devices with integral EMI filtering allows designers to reduce costs by eliminating an additional EMI filter part, the board space for the part and the part’s assembly.

MLV advantages

AVX TVS MLVs have many circuit protection performance advantages when compared to TVS diodes. MLVs have extremely fast response times of less than a nanosecond, which minimizes damage caused by transients.

Figure 5. TVS diodes and MLVs. Source: AVX

Figure 5. TVS diodes and MLVs. Source: AVX

MLVs are better at handling the temperature extremes experienced by electronic components within a vehicle. MLVs have no derating in performance over wide temperature ranges from -55° C to 175° C. TVS diodes derate significantly with temperature.

They also provide bi-directional protection in the on-state by clamping positive or negative transients. MLVs provide EMI filtering in the normal off-state in a circuit, which is important in communications buses. The low capacitance of MLVs minimizes signal distortion, which is an additional advantage in communications and data applications.

Figure 6. MLV and diode size comparison. Source: AVX

Figure 6. MLV and diode size comparison. Source: AVX

The combination of EMI and bi-directional protection enables MLVs to replace TVS diode pairs providing bi-directional protection and an EMI filter. In addition, MLVs are more compact or have smaller footprints compared to TVS diodes of equivalent power or voltage levels. Reducing the number of components and the size of components in a design can reduce assembly costs, circuit complexity, inventories and free up space for other devices.

TVS diodes are constructed with only one layer to dissipate a voltage spike while MLVs have several layers. MLVs can easily handle highly repetitive strikes because their multiple layers can dissipate more energy.

Figure 7. AVX TVS MLVs have zero derating across their full operating temperature range. Source: AVX

Figure 7. AVX TVS MLVs have zero derating across their full operating temperature range. Source: AVX

Summary

In summary, the key advantages of transient voltage suppressing MLVs are:

  • Size reduction when replacing a TVS diode of equivalent performance
  • No derating of MLVs with temperature (-55 to 175° C) – an industry first
  • Repetitive strike capability – diodes only have one layer, while MLVs can dissipate energy across multiple layers
  • Bidirectional protection
  • 3 to 1 part reduction compared to diode protection
  • EMI/RFI filtering
  • Enhanced reliability because the uniform, fine grained MLVs do not wear out
  • Meet ISO-7637 test requirements and qualified to AEC-Q200
  • Available in compact, surface-mount case sizes, as low as 0201

Electronics design engineers interested in evaluating the AVX TVS MLVs for automotive and other applications can find additional information in AVX’s Circuit Protection Application Guide and MLV Models. For samples to evaluate an electronic system under development, visit AVX.

Related

Source: Electronics 360, AVX Corporation

Recent Posts

TDK Increases Current Ratings of Automotive Thin-Film Power Inductors

1.7.2025
18

SCHURTER Unveils High Voltage Fuses for EV Applications

30.6.2025
9

YAGEO Releases First to Market 750V Aluminum Capacitors

30.6.2025
40

Murata Releases Worlds First 10µF/50V Automotive MLCC in 0805 Size

26.6.2025
53

Vishay Expands Automotive High Frequency Thin Film Chip Resistors

26.6.2025
24

KYOCERA AVX Releases Robust Vertical-Mating Battery Connectors

25.6.2025
10

Stackpole Releases Low VCR High Voltage Chip Resistors

23.6.2025
15

Samsung Electro-Mechanics Releases 0201 X7T 1uF 6.3V MLCC for ADAS Applications

19.6.2025
24

Murata Announces 0402 Automotive Chip Ferrite Beads for V2X

19.6.2025
29

TDK Releases Automotive Power-Over-Coax Inductor for Filters

18.6.2025
32

Upcoming Events

Jul 23
13:00 - 14:00 CEST

PCB design for a Smartwatch

Jul 29
16:00 - 17:00 CEST

Impact of Elevated Voltage and Temperature on Molded Power Inductors in DC/DC converters

View Calendar

Popular Posts

  • Buck Converter Design and Calculation

    0 shares
    Share 0 Tweet 0
  • Boost Converter Design and Calculation

    0 shares
    Share 0 Tweet 0
  • Flyback Converter Design and Calculation

    0 shares
    Share 0 Tweet 0
  • What is a Dielectric Constant and DF of Plastic Materials?

    4 shares
    Share 4 Tweet 0
  • LLC Resonant Converter Design and Calculation

    0 shares
    Share 0 Tweet 0
  • Ripple Current and its Effects on the Performance of Capacitors

    3 shares
    Share 3 Tweet 0
  • How to Design an Inductor

    0 shares
    Share 0 Tweet 0
  • Dual Active Bridge (DAB) Topology Explained

    0 shares
    Share 0 Tweet 0
  • SEPIC Converter Design and Calculation

    0 shares
    Share 0 Tweet 0
  • Why Low ESR Matters in Capacitor Design

    0 shares
    Share 0 Tweet 0

Newsletter Subscription

 

Passive Components Blog

© EPCI - Leading Passive Components Educational and Information Site

  • Home
  • Privacy Policy
  • EPCI Membership & Advertisement
  • About

No Result
View All Result
  • Home
  • Knowledge Blog
  • Premium Suppliers

© EPCI - Leading Passive Components Educational and Information Site

This website uses cookies. By continuing to use this website you are giving consent to cookies being used. Visit our Privacy and Cookie Policy.
Go to mobile version