PART NUMBER:
KXR94-2283
± 2g Tri-Axis Accelerometer
Specifications
Rev. -
July 2009
USING THE MULTIPLEXED OUTPUT OF THE KXR94
Multiplexer Data Select
The KXR94 features an integrated 4-channel multiplexer. This feature reduces system MCU
requirements to only 1 ADC and 2 digital I/O’s. The KXR94 uses two select inputs (S0, S1) to
control the data flow from Vmux. When a microprocessor toggles the select inputs, the desired
output is attained based on the select table. Note that logic 0 is GND and logic 1 is Vdd.
S1
0
0
1
1
S0
0
1
0
1
Vmux
X Output
Z Output
Y Output
Aux. In
Output Select Table
Data Sampling Rate
When operating in its multiplexed mode, the KXR94 has the ability to achieve very high data
sampling rates. Internally, the sensor elements (X, Y, and Z) are sequentially sampled in a “round
robin” fashion at a rate of 32KHz per axis. Note that this is a differential capacitance sampling of
each sensor element, which stores an analog voltage on the filter cap for each axis. Combine this
high sensor element sampling rate with the short 5µS settling time of the integrated multiplexer, and
the user can achieve a performance very close to that of the 3 separate analog outputs. This is
more than sufficient to eliminate any aliasing in the final application since the KXR94 will be
operating with a typical bandwidth of ~50Hz and a maximum of 1000Hz.
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