Data Sheet
FEATURES
High Performance Accelerometer with
Dual Spectrum Signal Processing
ADXL195/ADXL295
GENERAL DESCRIPTION
The
ADXL195/ADXL295
are dual spectrum accelerometers
that measure baseband acceleration in up to two axes (XL-X
and XL-Y), as well as high frequency (HF) acceleration energy.
Identical, independent X and Y sense structures are implemented
to achieve the best possible fail-safe performance.
The XL-X and XL-Y channels output baseband acceleration
information with a nominal full-scale range of ±120
g
and a
bandwidth of 408 Hz. The acceleration data is provided as a
12-bit, twos complement word with a resolution of 62.5 mg/LSB.
HF acceleration within the frequency band of 15.5 kHz to
23 kHz is rectified and filtered to generate an average
g
(g
AVG
)
energy measurement. The HF channel has a nominal full-scale
range of 40
g
AVG
and a bandwidth of 393 Hz. When combined
with the XL-X and XL-Y information, HF acceleration information
allows for enhanced vehicle impact detection and discrimination.
The
ADXL195/ADXL295
are available in a 16-lead, narrow-body
SOIC package with an exposed pad. The
ADXL195/ADXL295
can operate at 3.3 V and 5 V and are specified for operation from
−40°C to +105°C.
Single-axis (ADXL195) and dual-axis (ADXL295) configurations
±120
g
baseband acceleration channel
12-bit resolution at 62.5 mg/LSB
512 kHz data interpolation rate
40
g
AVG
high frequency signal processing channel
10-bit resolution at 83.3 mg avg/LSB
128 kHz data interpolation rate
Sensor frequency response down to dc
On-demand electromechanical self-test
On-demand HF signal injection self-test
Fully differential circuitry for high resistance to EMI/RFI
Independent x- and y-axis sense structures for robust
FMEA performance
Independent x- and y-axis arming thresholds
Low noise
1 LSB rms (12-bit baseband acceleration channel)
2 LSB rms (10-bit high frequency acceleration channel)
Qualified for automotive applications
Temperature range: −40°C to +105°C
3.3 V and 5 V operation
APPLICATIONS
Enhanced crash sensing
Shock detection
FUNCTIONAL BLOCK DIAGRAM
ARMING PIN
FUNCTIONALITY
SELF-
TEST
ARM_X
ARM_Y
STATE MACHINE
HF SELF-
TEST
GND
EPAD
MUX
AC
AMP
DEMOD
Σ-Δ
MOD
SINC
3
+ FIR FILTER
–3dB AT 408Hz
OFFSET/
SENSITIVITY
CALIBRATION
MUX
OFFSET
CANCELLATION
INTERPOLATION
AT 512kHz
REGISTERS/MEMORY
MISO
X-AXIS
SENSOR
SENSOR
DRIVERS
BAND-PASS
FILTER
15.5kHz TO
23kHz
SENSITIVITY
CALIBRATION
|ABS|
IIR, SINC, FIR
LOW-PASS
FILTERS
–3dB AT 393Hz
SPI INTERFACE
MOSI
INTERPOLATION
AT 128kHz
SCLK
CS
MUX
AC
AMP
DEMOD
Σ-Δ
MOD
SINC
3
+ FIR FILTER
–3dB AT 408Hz
OFFSET/
SENSITIVITY
CALIBRATION
OFFSET
CANCELLATION
INTERPOLATION
AT 512kHz
DEVICE ID
Y-AXIS
SENSOR
SENSOR
DRIVERS
TIMING
GENERATOR
OTP
MEMORY
TRIM
CONFIGURATION
VOLTAGE
REGULATOR
VDD
VREG
10496-001
Figure 1.
For more information about the
ADXL195/ADXL295,
please contact the Analog Devices, Inc.,
Customer Interaction Center
at
http://www.analog.com/en/content/technical_support_page/fca.html to connect with a technical support specialist.
Rev. SpA
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