Automotive Electronics

Applications Guide

2 3

CONTENTS

Develops 1200V

SiC MOSFET for

battery charging

applications

2017

The ﬁrst blade-type

ATO (Autofuse

)

Fast Acting Fuse,

now considered

the global

standard

1976

Introduces industry’s

ﬁrst centralized under-

dash fuse block

1950

Littelfuse

invents the ﬁrst

automotive fuse

1930

Topic Page

Electrical Threats and New Automotive Technologies 4–5

Automotive Applications in Modern Vehicles 6–7

Automotive Circuit Protection Applications Matrix 8–11

Energy Storage System 12

Battery Module 13

On-board Battery Charger 14

Traction Motor Inverter 15

DC/DC Converter 16

Battery Distribution Unit 17

Active Clamping 18

Ignition System 19

Motor Control 20

Engine Cooling System 21

Infotainment and Navigation 22

Vehicle Communication 23

Emergency Call (eCall) 24

Sensor Fusion 25

Radar System 26

Camera 27

Remote Keyless Entry 28

Lighting – Inside Cabin 29

Lighting – Headlamps 30

Global Lab Capabilities 31

About this guide

This guide provides a summary of key circuit protection consideration factors, descriptions of

the technologies Littelfuse offers, and product selection tables. It is designed to help you quickly

ﬁnd a protection solution appropriate to your application.

Speciﬁcations, descriptions, and illustrative material in this literature are as accurate as known at the time of

publication, but are subject to changes without notice. Visit Littelfuse.com for more information.

Use Our Deep Experience

for Your Automotive Application

Littelfuse: Everywhere, Every Day

Founded in 1927, Littelfuse has become the world’s most respected

circuit protection brand, with well-established and growing

platforms in power control and sensing technologies. Today, we

are a global company, offering a diverse and extensive product

portfolio—fuses, semiconductors, polymers, ceramics, relays,

sensors, and more—serving the electronics, automotive, and

industrial markets. Each is manufactured to exacting quality

standards and backed by an unwavering commitment to technical

support and customer service.

Our history of innovation, combined with our customer-ﬁrst

culture, drives us to collaborate with you to develop safer, more

reliable products that are energy efﬁcient and compliant with

global regulations. We will partner with you to solve complex

problems wherever electrical energy is used, bringing design,

engineering, and technical expertise to deliver business results.

Why Choose Littelfuse

Littelfuse introduced the ﬁrst of what would become a long

line of automotive circuit protection technologies in the 1930s,

with the design and development of the original automotive

fuses. That commitment to the automotive industry continues

today as vehicles have become increasingly dependent on

high-powered electronics.

Littelfuse supports automotive designers with a global network

of test labs and design and manufacturing facilities across four

continents, including China’s second-largest semiconductor

fabrication facility. Our Silicon Valley Technology Center supports

the complete innovation life cycle, from new materials and product

concepts to product design, prototyping, testing, and validation.

Customer Focus

A customer-ﬁrst approach is at the heart of our company-wide

culture, driving us to build long-lasting relationships and exceed

expectations. Every day, it’s our employees who make the difference

for your business. They listen to your needs and understand your

challenges. They use their knowledge and expertise to develop the

best solutions and solve your problems.

Application Expertise

At Littelfuse, we partner with customers to design, manufacture, and

deliver innovative solutions for a wide range of markets including

automotive and commercial vehicles, industrial applications, data and

telecommunications, medical devices, consumer electronics, appliances,

and transportation. Our expertise involves applying reliable and efﬁcient

product solutions, innovative technologies, and global resources to

address technical challenges in a variety of applications. Our worldwide

network of research teams focuses on product development and support,

design-in programs, and application testing in our global labs.

Operational Excellence

With our global manufacturing footprint, Littelfuse is ﬁrmly committed to

manufacturing quality products at a competitive price. We build quality

into our products and services, striving for zero defects in everything

we do, thereby reducing cost and increasing your total satisfaction. We

strive to exceed your expectations every day.

Quality Assurance

Our global manufacturing facilities abide by strict quality assurance

requirements and hold the following quality management system

registrations:

• ISO 9001

• ISO14001

• IATF 16949

Protect. Control. Sense.

Littelfuse offers leading technologies in circuit protection, power

control, and sensing. We continue to expand our broad and diverse

portfolio of products into adjacent markets, including Power

Semiconductors, heavy-duty Switches, Magnetic, Optical,

Electromechanical, and Temperature Sensors as well as other products

that provide safe control and distribution of electrical power.

Electrical Threats

THREAT: ELECTROSTATIC DISCHARGE (ESD)

ESD is characterized by fast rise times and high peak voltages and currents up to 30A, which

can melt silicon and conductor traces. Even when ESDs don’t cause catastrophic failures,

electrical currents due to ESD can change the state of internal logic, causing a system to

latch up and behave unpredictably or cause corruption of a data stream. Without adequate

protection, ESD can damage control units, infotainment electronics, sensors, fuel injectors,

valves, motors, powertrains, and dozens of other components. Sometimes, a component or

circuit is damaged by ESD, creating latent defects that later progress to premature failures.

TVS Diode Arrays

Because of their high-speed response to overvoltages, TVS

Diode Arrays are widely used for ESD protection in automotive

electronics. Automotive-qualiﬁed SPA

TVS Diode Arrays from

Littelfuse are available in a range of compact surface-mount

packages to ﬁt into any layout.

Electrical Threats and

New Automotive Technologies

THREAT: OVERLOADS/SHORT-CIRCUIT CURRENTS

Sustained overloads will cause circuit components to overheat, potentially leading to catastrophic

and uncontrolled failures of the vehicle’s electrical system. Short circuits can surpass the capabilities

of the wires, connectors, etc. in the power circuit, which can also lead to uncontrolled failures or

possibly a thermal event.

Resettable PPTC Overcurrent

Protection Devices

Littelfuse Polymeric Positive Temperature Coefﬁcient (PPTC) devices are

widely used in automotive applications like wiring harness and network

protection, communication and infotainment systems, and EV battery

management systems. Unlike Fuses, these devices provide resettable

protection for automotive electronics against damage from harmful

overcurrent surges. Bladed, leaded, and surface-mount form factors are

available for automotive applications.

Fuses

Automotive Fuses protect components or circuits by melting under

overcurrent conditions to interrupt current ﬂow. In addition to

withstanding rapid temperature cycles and vibration, they must offer

long-term stability and AEC-Q test compliance. Littelfuse offers an

unparalleled range of automotive Fuses, from cartridge and blade styles

to surface-mount chip Fuses.

THREAT: SWITCHING LOADS IN POWER ELECTRONICS CIRCUITS

In modern automotive designs, all on-board electronics are connected to the battery

and the alternator. However, the output of the alternator is unstable and requires further

conditioning before it can be used to power the vehicle’s other systems. During the

powering or switching of inductive loads, the power is temporarily interrupted, and

unwanted voltage spikes or transients are generated. If left unchecked, these transients

would be transmitted along the power line and into the electronic modules.

Varistors

Automotive-qualiﬁed Metal Oxide Varistors (MOVs) and Multilayer Varistors

(MLVs) protect against voltage transients induced by load dump and other

transient events. When exposed to high-voltage transients, the varistor

impedance changes by many orders of magnitude—from a near open-

circuit to a highly conductive level—clamping the transient voltage to a

safe level. Choose from radial-leaded MOVs in disc sizes from 5mm to

20mm. Also, surface-mounted MLVs are available.

Power Semiconductors

Power semiconductor devices enable the next generation of vehicles by

managing power ﬂexibly. Fast-switching SiC technology increases power

density and energy efﬁciency in systems like on-board battery chargers.

The Littelfuse power semiconductor portfolio includes Thyristors,

Rectiﬁers, Fast Recovering Diodes, IGBTs, and wide band gap devices.

OPPORTUNITY: ELECTRIFYING THE VEHICLES OF TOMORROW

Researchers predict that by 2025, a typical high-end vehicle will contain more than $6,000

worth of electronics. The growing interest in self-driving vehicles, vehicle-to-vehicle and vehicle-

to-infrastructure communications, and on-board safety, convenience, and environmental

features ensures that the sheer number of electronic components per vehicle will continue to

expand rapidly. Additionally, as hybrid-electric vehicles become increasingly popular, power

semiconductors will be critical to the next generation of Battery Management Systems and

on-board/off-board charging systems.