New diodes target automotive and communication industries

By Jean-Jacques
DeLisle, contributing writer

Diodes
can be found in many devices across a multitude of fields. A diode, simply put,
is a semiconductor that allows an electric current to flow in only one
direction, making it an essential part of many applications. Recently, several
major manufacturing companies have released new diodes aimed at automotive and
communication industries.

Companies
such as Bourns, Littelfuse, and Nexperia have already
produced new diodes that deliver many advantages over their predecessors.

 

Bourns
Inc., for example, rolled out a new TVS diode series that features
low capacitance of 3 picofarads (pF), a feature that makes them well-suited
protection devices for the high-speed interfaces and other applications that
require low capacitance. Model CDSOD323-TxxC-DSLQ TVS diodes also offer Bourns’
lowest TVS diode leakage current of just 1 nanoampere (nA). These diodes are
essential for IoT sensors and other applications in which long-lasting battery
life is important. TVS diodes aid these sensors and other automotive tech by
being more efficient and wasting less energy, which allows the automotive
equipment to run longer and consume less power, a boon for anyone designing and
manufacturing them.

 

David
Scoffield, TVS diode product manager at Bourns, provided some insight into how
these new diodes work. “A TVS diode protects interface lines by connecting to
protective grounds. During normal situations, the TVS diode should be
transparent and look like an open circuit to ground. Any parasitic capacitance,
or leakage, to ground would cause distortion to the signal on the line. The
line signal of high-speed interfaces is especially sensitive to such parasitic
capacitances and leakage. Hence to preserve signal integrity it is important to
ensure protective devices on the line have minimal capacitance and leakages.”

 

This
means the new diodes are more efficient and waste far less energy, a quality
that makes them highly desirable for automotive industries and other similar
applications.

 

Scoffield
explained that the electronification of the automotive industry is leading to
significant growth in the amount of data that is being collected, transmitted
and processed. “High-speed interfaces are being used in the transmission of
voluminous data,” he said. “Some of these interfaces are subject to ESD whether
due to being exposed to the user, e.g. USB3.0 ports and touchscreens, or due to
the functionality and environment.”

Nexperia, a former Standard Products division of NXP, also has released several new diodes with some
extremely advanced features. The new parts are interchangeable drop-in
replacements for legacy devices. To make these new diodes compatible, they will
be available in standard SOT23, SOD323 and SOT323 packages.

 

Nexperia
has developed new parts that deliver higher performance in a variety of ways.
The new PESD2IVN24-T part, for example, delivers 30 kV ESD protection over the
previous 23-kV models. These new models also feature an improved surge current
of 3.5 A and an advanced clamping voltage of 42 V at 3.5 A (compared to 70 V at
3 A for the legacy part).  Other features
of the diodes are similar to previous models, but with small advancements. The
idea is to make diodes that are far better than previous models, but not so
different that they would not be interchangeable. 

Image source:
NXP.

“In modern vehicles, there is an increasing amount of data exchange and the
electronic content is growing in functionality and complexity, therefore
effective ESD protection solutions are imperative. Nexperia has brought online
a massive capacity increase for ESD diodes in order to guarantee a secure
chain, and provide customers with peace of mind that they are protecting the
electronics in their vehicles with high-performance, rugged and efficient
devices,” said André Dressler, Nexperia’s marketing manager automotive.

 

Littelfuse
is another company that is following the trend of more efficient, advanced
diodes and has released several new models. Among these new models are the AQHV
and AQHV-C series that are designed to give extremely fast acting, high performance,
over-voltage protection. These are suited for power interfaces, passenger
charging interfaces, as well as LED lighting modules, and low speed I/Os. Typical
applications include ESD protection for
automotive electronics, LED lighting
modules, mobile/handheld devices, CAN BUS (drive-by-wire), LIN BUS, RS-232 and
RS-485 interfaces, general-purpose low-speed I/Os, and portable instrumentations.

 

“As
AEC-Q101 qualified devices, the AQHV and AQHV-C Series can ensure maximum
reliability in the harshest environments,” said Tim Micun, director of TVS
diode arrays (SPA diodes) at Littelfuse in a press release. “That makes
them a great option for designers who need to replace passive ESD protection or
to ‘sprinkle’ protection devices around a printed circuit board.”

The rise of such diodes is part of a trend seen in many areas around the tech
world. Smaller, more powerful components are allowing designers to revamp older
designs. This allows developers to increase efficiency and power without having
to ‘go back to the drawing board’ and start over completely. By designing these
new diodes to effectively be ‘dropped in’ as needed, developers can replace an
older model or increase the efficiency of a device without having to redesign
the entire system.

 

Littelfuse’s
TVS diode arrays are capable of handling >1000 ESD strikes or surge
transients without performance degradation. This improved longevity is an
advancement that comes in contrast to alternative technologies that have an
inherent wear-out factor and low dynamic resistance. These models provide up to
60 percent lower clamping voltages. These advancements coupled with the ESD
protection up to ± 30 kV, and surge protection up to 8 A, help equipment
manufacturers comply with exceedingly harsh industry standards, and may
significantly extend the life of technical equipment and improve system uptime.