November 2015
38
M
emories
they are giving this segment. Among them are
NXP, Freescale, Qualcomm, TI, Sony, MTK,
Intel, Infineon and others. Of course, ARM as
a licensor is heavily engaged in this realm as
well. Another market segment offering good
prospects for high sales volumes, which could
gain in importance in the mid-term, is smart
lighting and smart metering, plus home secu-
rity and home control systems equipped with
thermostats and related equipment. However,
this segment may attract a smaller number
of device vendors since it involves different,
somewhat higher demands on product qual-
ity. Macronix is set to contribute to these
emerging markets through specific incremen-
tal improvements of non-volatile memory
devices, especially in regard to ultra-low power
and standby modes. In stark contrast to the
more broadly defined Internet of Things, with
its complex infrastructure and fast transfer of
large amounts of data, the wearable devices
segment calls for a pragmatic system partition-
ing. Wearables, per definition, are the smallest
possible data systems to be worn close to the
human body. If they were larger they wouldn’t
be wearables anymore. Wearables, in contrast
to smart phones and multimedia systems, don’t
require high memory densities and large mem-
ory spaces since they connect wirelessly with
their dedicated base stations.
The new serial NOR flash MX25R Series was
specifically designed and laid out for the rel-
evant performance requirements of wearable
devices – that is, eliminating all non-essential
structures and features. Among other mea-
sures, the internal buffers were tailored to
the envisioned applications, whereas a typ-
ical high-performance memory cell would
comprise large internal RAMs. In wearable
applications, when focusing on frequencies of
just a few megahertz, there are further routes
for optimization to reduce die size and power
consumption, while maintaining all options
for system designers to still utilize special
‘performance modes’ - at the cost of higher
power consumption. In its deep-power-down
(current-saving) mode the MX25R devices
offer a very favorable power budget, with sav-
ings of more than 90 percent compared to tra-
ditional solutions.
In regard to connecting the memory device
with the system environment, the MX25R is
compatible with the well known and wide-
ly-used standard serial NOR flash inter-
face. This eliminates additional development
efforts on the user side and it accelerates time
to market. With regard to active current, the
MX25R device – drawing 4mA (8mA peak)
- is situated at the lower end of the range avail-
able in the market. As a first estimation the
active current of the device is 70 percent lower
than with traditional last-generation memory
solutions: in deep-power-down mode the dif-
ference goes up to more than 90 percent.
With its wide supply voltage range of 1.7V to
3.6V, the new memory series not only con-
sumes less power during standard operation
but enables designs to operate over the full
Vcc range of the battery, thereby eliminating
the need for external regulators. MX25R-
based applications continue to operate even
when the remaining battery capacity goes
down to voltages below 2.7V. This further
extends battery life by up to 50 percent.
n
Figure 2. USON and WLCSP packages for the Macronix serial NOR flash MC25R series
Figure 3. Performance overview of the serial NOR flash series in regard to active current,
deep-power-down consumption and battery lifetime in wearables
Figure 4. Inspecting a batch of memory devices at Macronix in HsinChu, Taiwan.
