February 2015
34
M
icrocontrollers
& S
o
C
s
Small Microcontroller
devices for a big market
By Kathleen Jachimiak,
Freescale
Kinetis mini MCUs from Freescale,
such as the KL03 chip-scale package
measuring just 1.6 mm by 2.0 mm
with corresponding ultra-low
power consumption, are well-suited
to support next-generation IoT
designs, including medical, monito-
ring, and other wearable applications.
Huge volumes of data, billions of connec-
tions, boundless opportunities: these are
terms often used to describe the Internet
of Things (IoT). IoT is big, huge, and gigan-
tic – we all understand that. In fact the only
thing that is small in regard to IoT is the size
of some of the devices that people will use to
stay connected. Many designers focus their
IoT design considerations around perfor-
mance, sensing capability, and communica-
tion protocols. However, for many of the use
cases within IoT, the implementation is not
practical without a physically small – or mini
– device. And as these devices grow in prod-
uct requirements and technical complexity, so
will the product size – unless companies take
the opportunity to start designing for space
optimization as well.
Semiconductors play a big role in enabling
customers to reach their design goals of
optimization by integrating more function-
ality into smaller chips. In fact, Moore’s Law
already tells us that the number of transistors
on integrated circuits (IC) will double approx-
imately every two years. So, it is only natural
to assume that chips will grow in functionality
and not size. However, we see that IC pack-
aging innovation is becoming an important
supplement to Moore’s Law. We no longer are
integrating more into the same sized pack-
age. Instead, we are integrating more into
smaller-sized packages. But again, it’s not
only about size. As smart portable devices
are increasingly replacing traditional PCs
and other electrical equipment, sophisticated
packages are needed to deliver high-perfor-
mance applications in a low-profile, low-cost,
and low power design. Freescale is a technol-
ogy innovator that is delivering the required
high level of on-chip integration in indus-
try-leading tiny packages with Kinetis mini
MCUs based on wafer-level chip-scale pack-
ages (WLCSP). The most recently announced
Kinetis mini MCU brings small to a whole
new level. The Kinetis KL03 chip-scale pack-
age is the smallest ARM-based device at just
1.6 mm by 2.0 mm. That is 35% smaller than
any other competing 32-bit ARM-based
MCU, and smaller than a golf ball dimple. In
fact, more than 20,000 of them would fit into
a standard size golf ball.
But smaller chips do not necessarily equate
to fewer features or less functionality - not by
Freescale standards at least. Chips can be small
and smart by offering optimal performance
and key features on-chip to further save PCB
board space for designers. More designers are
choosing to start with a 32-bit MCU architec-
ture in order to support complex algorithms,
connectivity stacks, and HMIs. By adding
on-chip memory, powerful timers, and a series
of communications interfaces, the Kinetis
KL03 MCU, utilizing a 48 MHz ARM Cor-
tex-M0+ core, adds more functionality and
GPIO than competing solutions, and is the
first Kinetis L device to offer an on-chip ROM
bootloader for easy flash upgrade. So this chip
is truly feature-rich and small.
Designers select small devices because they
are building something small, and if you are
building a small device, chances are it is small
because it needs to be portable … and if it is
portable, it likely needs to run on a battery
and for sure needs to be energy efficient to
maximize product longevity between charges.
Having a great throughput/mA number is
only one of many considerations taken when
designing a system to minimize power with-
out sacrificing performance.
The Kinetis KL03 MCU redefines the “low”
in low power, offering the most energy-effi-
cient ARM-based MCU. Based on the ultra-
low power ARM Cortex-M0+ core and smart
low-power architecture, Kinetis KL03 devices
achieve a run power consumption of less than
41 µA/MHz. To further demonstrate the bene-
fit of flexible low power, let’s take the example
of a wearable IoT application such as a fitness
watch. A fitness watch has multiple operating
modes, which benefits customers since they
get loads of functionality in addition to just
the basic watch – things like heart rate monitor,
