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unique in the market, filling the
gap between less feature rich
discrete solutions and single-chip
sensor interface AFEs that include
processing power. Consuming only
457µA supply current and only
36mm2 of real-estate, the XR10910
offers the industry’s smallest, lowest
power interface for 16 analog
sensors. The XR10910 will be the
first in a growing family of easy-
to-use sensor interface products
from Exar. Smaller channel count
versions are on the horizon as
well as versions that offer digital
outputs.
Sensors enable the smart products
and technology we use every day.
Sensor conditioning products like
the XR10910 will continue to play
a key role in how these sensors
interface with our ever growing
digital world. Designers will continue
to weigh the benefits of integrated
AFEs versus discrete solutions
and semiconductor manufacturers
will continue to expand the AFEs
offered in an effort to supply AFEs
to a broader market space.
certainly will not fit every sensor
interface requirement out there. If
performance is the designers’ top
priority and you cannot find an AFE
on the market designed specifically
for your application, then a discrete
solution will usually be the preferred
method because the designer can
hand-pick the components to best
fit his/her needs. Ultimately fine
tuning the sensor conditioning
block.
Comparing AFEs
AFEs on the market today offer
different levels of integration. Some
include an ADC or processing power,
while others like the XR10910 do not.
Most sensor interface AFEs on the
market are very application specific,
thus their performance feature set
and functional blocks are extremely
useful when used in the target
application. For example, there are
several AFEs on the market today
that were designed for medical
instrumentation applications and
integrate 16-bit or 24-bit delta-
sigma ADCs, PGAs and a host
of features designed to reduce
size, power, and time to market
if you happen to be designing an
ECG (electrocardiogram) or other
medical diagnostic equipment.
But if you are a designer with the
challenge of conditioning multiple
Hall Effect sensors, as described
above, this highly integrated AFE
is not the answer. Something with
less integration and more flexibility
is needed.
Conclusion
Sensor interface AFEs tend to offer
faster time to market, higher ease
of use, smaller footprint and in
many cases lower power. But many
are extremely specialized for certain
applications and are not able to
support multiple sensors or multiple
types of sensors. Discrete solutions
tend to be more flexible and can
be fine-tuned to each specific
application, but they require analog
design prowess, more real-estate,
more power, and tend to lack
many automated features like auto
calibration to correct for sensor
drift.
The XR10910 feature set truly
Function
Integrated AFE (XR10910)
Discrete Solution
Footprint
Power Consumption
Footprint
Power Consumption
16:1 differential mux
6mm x 6mm
(QFN)
0.5mA
~ 7mm x 7mm
(16:1 diff MUX in
LFCSP)
~0.01mA
Digitally controlled
PGA
~ 4mm x 3.75mm
(Digitally program-
mable amp in
LFCSP)
~1.8mA
Offset correction
~2mm x 2mm (10-
bit DAC in SC70) +
~2mm x 2mm (amp
in SC70)
~0.08mA + ~0.1mA
LDO to power sensors
~2mm x 2mm
(LDO in LFCSP)
~0.09mA
Total
36mm
2
0.5mA
76mm2
2.08mA
Sensors
Special Edition
New-Tech Magazine Europe l 47