؎5 g to ؎50 g, Low Noise, Low Power,
Single/Dual Axis iMEMS Accelerometers
a
ADXL150/ADXL250
FUNCTIONAL BLOCK DIAGRAMS
FEATURES
Complete Acceleration Measurement System
on a Single Monolithic IC
TP
(DO NOT CONNECT)
80 dB Dynamic Range
+V
2
S
+V
S
ADXL150
Pin Programmable ؎50 g or ؎25 g Full Scale
Low Noise: 1 mg/√Hz Typical
Low Power: <2 mA per Axis
Supply Voltages as Low as 4 V
2-Pole Filter On-Chip
5k⍀
0.1F
GAIN
AMP
V
OUT
SENSOR
DEMODULATOR
25k⍀
BUFFER
AMP
CLOCK
9
Ratiometric Operation
COM
SELF-TEST
Complete Mechanical & Electrical Self-Test
Dual & Single Axis Versions Available
Surface Mount Package
OFFSET
NULL
X OFFSET
NULL
TP
(DO NOT CONNECT)
BUFFER
AMP
ADXL250
25k⍀
+V
S
GAIN
AMP
V
V
X
Y
OUT
0.1F
DEMODULATOR
SENSOR
GENERAL DESCRIPTION
5k⍀
+V
2
S
The ADXL150 and ADXL250 are third generation ±50 g sur-
face micromachined accelerometers. These improved replace-
ments for the ADXL50 offer lower noise, wider dynamic range,
reduced power consumption and improved zero g bias drift.
CLOCK
5k⍀
GAIN
AMP
OUT
SENSOR
DEMODULATOR
25k⍀
BUFFER
AMP
The ADXL150 is a single axis product; the ADXL250 is a fully
integrated dual axis accelerometer with signal conditioning on a
single monolithic IC, the first of its kind available on the com-
mercial market. The two sensitive axes of the ADXL250 are
orthogonal (90°) to each other. Both devices have their sensitive
axes in the same plane as the silicon chip.
COM
Y OFFSET
NULL
SELF-TEST
ratiometric to the power supply, eliminating the need for a volt-
age reference when driving ratiometric A/D converters such as
those found in most microprocessors. A power supply bypass
capacitor is the only external component needed for normal
operation.
The ADXL150/ADXL250 offer lower noise and improved
signal-to-noise ratio over the ADXL50. Typical S/N is 80 dB,
allowing resolution of signals as low as 10 mg, yet still providing
a ±50 g full-scale range. Device scale factor can be increased
from 38 mV/g to 76 mV/g by connecting a jumper between
VOUT and the offset null pin. Zero g drift has been reduced to
0.4 g over the industrial temperature range, a 10× improvement
over the ADXL50. Power consumption is a modest 1.8 mA
per axis. The scale factor and zero g output level are both
The ADXL150/ADXL250 are available in a hermetic 14-lead
surface mount cerpac package specified over the 0°C to +70°C
commercial and –40°C to +85°C industrial temperature ranges.
Contact factory for availability of devices specified over automo-
tive and military temperature ranges.
i
MEMS is a registered trademark of Analog Devices, Inc.
REV. 0
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use, nor for any infringements of patents or other rights of third parties
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© Analog Devices, Inc., 1998