ADXL190 [ADI]
Low Cost +-100 gSingle Axis Accelerometer with Analog Output; 低成本+ -100 gsingle类型转换轴加速度传感器与模拟输出
| 型号： | ADXL190 |
| 厂家： | 
ADI |
| 描述： | Low Cost +-100 gSingle Axis Accelerometer with Analog Output |
| 文件： | 总5页 (文件大小：96K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Low Cost ؎100g Single Axis
Accelerometer with Analog Output
a
ADXL190*
FEATURES
FUNCTIONAL BLOCK DIAGRAM
iMEMS® Single Chip IC Accelerometer
40 Milli-g Resolution
Low Power 2 mA
TP
(DO NOT CONNECT)
+V
2
S
400 Hz Bandwidth
+5.0 V Single Supply Operation
2000 g Shock Survival
+V
S
ADXL190
0.1F
5k⍀
GAIN
AMP
V
OUT
SENSOR
DEMODULATOR
APPLICATIONS
Shock and Vibration Measurement
Machine Health
BUFFER
AMP
25k⍀
CLOCK
9
COM
Shipping Recorders
SELF-TEST
ZERO g ADJUST
Military Fuze, Safe and Arm
delay. The –3 dB frequency of the poles is preset at the factory
to 400 Hz. These filters are also completely self-contained and
buffered, requiring no external components.
GENERAL DESCRIPTION
The ADXL190 is a complete acceleration measurement system
on a single monolithic IC. It contains a polysilicon surface-
micromachined sensor and signal conditioning circuitry to
implement an open-loop acceleration measurement architecture.
The ADXL190 is capable of measuring both positive and nega-
tive accelerations up to ±100 g, making it suitable for shock and
vibration measurement.
The product features a built-in self-test feature that exercises
both the mechanical structure and electrical circuitry. When
triggered by a logic high on the self-test pin, an electrostatic
force acts on the beam equivalent to approximately 20% of full-
scale acceleration input, and thus a proportional voltage change
appears on the output pin. No external components other than a
decoupling capacitor are required.
Typical noise floor is 4 mg/√Hz allowing signals below 40 milli-g
to be resolved. The ADXL190 can measure both dynamic accel-
erations, (typical of vibration) or static accelerations, (such as
inertial force or gravity).
The ADXL190 is available in a hermetic 14-lead surface mount
cerpak, specified over the –40°C to +105°C temperature range.
The ADXL190 has a two-pole Bessel switched-capacitor filter.
Bessel filters, sometimes called linear phase filters, have a step
response with minimal overshoot and a maximally flat group
*Patent Pending.
i
MEMS is a registered trademark of Analog Devices, Inc.
REV. 0
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700
Fax: 781/326-8703
World Wide Web Site: http://www.analog.com
© Analog Devices, Inc., 1999
(T = TMIN to TMAX, VS = +5 V, Acceleration = 0 g unless otherwise noted)
ADXL190–SPECIFICATIONS
A
ADXL190WQC
Parameter
Conditions
Min
Typ
Max
Units
SENSOR INPUT
Dynamic Range1, 2, 3
Alignment Error
Nonlinearity
Without Zero-g Adjust
±105
g
±1
0.2
±2
Degrees
%
%
Cross Axis Sensitivity
SENSITIVITY
Initial4
Ratiometric
∆ from +25°C
16.5
2.3
18.0
±0.5
19.5
2.7
mV/g
%
Temperature Drift5
ZERO g BIAS LEVEL
Initial2, 3
Ratiometric
∆ from +25°C
2.5
1.0
0.50
30
V
0 g Offset vs. Temperature5
Zero g Adjustment Gain
Zero g Adjust Pin Input Impedance
g
0.45
20
0.55
40
∆VOUT/∆V 0 g Adjust
kΩ
NOISE PERFORMANCE
Noise Density
4
12
mg/√Hz rms
FREQUENCY RESPONSE
3 dB Bandwidth
Sensor Resonant Frequency
360
400
24
Hz
kHz
SELF-TEST
Output Change6
Logic “1” Voltage
Logic “0” Voltage
Input Impedance
450
3.5
990
1.0
mV
V
V
50
kΩ
ANALOG OUTPUT
Output Voltage Range
Capacitive Load Drive
I
OUT = ±100 µA
0.25
1000
VS – 0.25
V
pF
POWER SUPPLY
Specified Performance
Quiescent Supply Current
4.75
5.25
5.0
V
mA
2.0
TEMPERATURE RANGE
Specified Performance
–40
+105
°C
NOTES
1Product is tested at ±50 g, and the combination of 0-g error, sensitivity error, and output voltage swing measurements provide the calculations for dynamic range.
20-g is nominally VS/2. Use of the 0-g adjustment pin is used to null the 0-g error, resulting in increased dynamic range. It can also be used to create an asymmetrical
dynamic range if so desired.
3The output response is ratiometric and is described by the following equation. VOUT (accel, VS) = [VS/2 ±(a VS/5 V)] + [(accel) (b VS + c VS2)(1 ± 0.08)]
Where a = 0.2 V, b = 2.712 × 10–3 1/g , c = 0.178 × 10–3 1/g/V.
4Measured at 100 Hz, ±50 g.
5Specification refers to the maximum change in parameter from its initial value at +25°C to its worst case value at TMIN or TMAX
6ST pin Logic “0” to “1”; ∆VOUT = (∆VOUT @ 5 V) × (VS/5 V).
.
All min and max specifications are guaranteed. Typical specifications are not tested or guaranteed.
Specifications subject to change without notice.
–2–
REV. 0
ADXL190
ABSOLUTE MAXIMUM RATINGS*
PIN CONFIGURATION
Acceleration (Any Axis, Unpowered for 0.5 ms) . . . . . .2000 g
Acceleration (Any Axis, Powered for 0.5 ms) . . . . . . . .1000 g
+VS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .–0.3 V to +7.0 V
Short Circuit Duration (Any Pin to Common) . . . . Indefinite
Operating Temperature . . . . . . . . . . . . . . . . –55°C to +125°C
Storage Temperature . . . . . . . . . . . . . . . . . . –65°C to +150°C
14
13
12
11
10
9
1
2
3
4
5
6
7
NC
NC
NC
NC
V
S
V
S
NC
NC
V
ADXL190
TOP VIEW
(Not to Scale)
TEST POINT
(DO NOT CONNECT)
OUT
*Stresses above those listed under Absolute Maximum Ratings may cause perma-
nent damage to the device. This is a stress rating only; the functional operation of
the device at these or any other conditions above those indicated in the operational
sections of this specification is not implied. Exposure to absolute maximum rating
conditions for extended periods may affect device reliability.
NC
SELF-TEST
8
COMMON
ZERO g ADJUST
NC = NO CONNECT
Drops onto hard surfaces can cause shocks of greater than 2000 g
and exceed the absolute maximum rating of the device. Care
should be exercised in handling to avoid damage.
Figure 1 shows the response of the ADXL190 to the earth’s
gravitational field. The output values shown are nominal. They
are presented to show the user what type of response to expect
from each of the output pins due to changes in orientation with
respect to the earth.
PIN FUNCTION DESCRIPTIONS
PIN 1
PIN 1
Pin No.
Function
1
14
7
8
1
1, 2, 3, 4, 6, 11, 12
No Connect
5
Test Point (Do Not Connect)
14
7
8
7
8
9
10
Common
Zero g Adjust
Self-Test
VOUT
TYPICAL OUTPUT AT
PIN 10 = 2.500V
TYPICAL OUTPUT AT
PIN 10 = 2.482V
8
7
14
1
8
7
13, 14
VS
1g
1
14
PACKAGE CHARACTERISTICS
PIN 1
PIN 1
TYPICAL OUTPUT AT
PIN 10 = 2.500V
TYPICAL OUTPUT AT
PIN 10 = 2.518V
Package
JA
JC
Device Weight
14-Lead Cerpak
+110°C/W
+30°C/W 5 Grams
EARTH'S SURFACE
Figure 1. ADXL190 Response Due to Gravity
ORDERING GUIDE
#
Axis
Specified
Voltage
Temperature
Range
Package
Description
Package
Option
Model
ADXL190WQC
1
+5 V
–40°C to +105°C
14-Lead Cerpak
QC-14
CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily
accumulate on the human body and test equipment and can discharge without detection.
Although the ADXL190 features proprietary ESD protection circuitry, permanent damage may
occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD
precautions are recommended to avoid performance degradation or loss of functionality.
WARNING!
ESD SENSITIVE DEVICE
REV. 0
–3–
ADXL190
APPLICATIONS
Table I. Offsets Produced Using the Circuit in Figure 3 for VS
= 5 V
All the circuitry needed to drive the sensor and convert the
capacitance change to voltage is incorporated on-chip requiring
no external components except for standard power supply de-
coupling. Both sensitivity and the zero-g value are ratiometric to
the supply voltage, so that ratiometric devices following the
accelerometer (such as an ADC, etc.) will track the accelerom-
eter if the supply voltage changes. The output voltage (VOUT) is
a function of both the acceleration input (a) and the power
supply voltage (VS) as follows:
Offset Voltage
Produced
P1
P0
Offset in g
Three-State
Three-State
0 mV
0
Three-State
0
0
0
–71 mV
–134 mV
–191 mV
71 mV
–4
Three-State
0
1
–7.4
–10.6
4
Three-State
V
OUT = VS/2 – (Sensitivity × VS/5 V × a)
1
1
Three-State
1
134 mV
191 mV
7.4
10.6
Adjusting the 0 g Bias Level
In some cases the user may have an asymmetrical input or may
want to fine adjust the zero-g output level to obtain maximum
dynamic range. The zero-g level is adjusted by supplying a
voltage to the zero-g adjustment pin (see Figure 2).
Another way to adjust the zero g offset is to supply a voltage to
the ZERO g ADJUST pin. The difference between VS/2 and
the voltage at the ZERO g ADJUST pin is reduced by a factor
of 6 (as a result of the internal 5 kΩ and 25 kΩ voltage divider)
and then multiplied by a factor of 3 in the output stage of the
ADXL190 resulting in a total gain of 0.5. Offset is thus de-
scribed by the following equation:
+V
2
S
GAIN = 3
FILTER
5k⍀
ADXL190
Offset (V) = (Voltage at the ZERO g ADJUST Pin – VS/2)/2
V
OUT
ACCELERATION
SIGNAL
This voltage may be produced by a variety of methods includ-
ing a PWM signal from a microcontroller. Care must be taken
that the output impedance of this voltage source is less than
5 kΩ and that there is very little ripple (noise). Any noise at the
ZERO g ADJUST pin will cause output errors.
25k⍀
ZERO g ADJUST
C2
0.1F
+V
S
200k⍀
If an asymmetric range of acceleration is required (e.g., +75 g
to –125 g) a resistor may be connected between the ZERO g
ADJUST and ground or VS as described above. For example:
Figure 2. Optional Zero-g Adjust Circuit Detail
Any voltage difference between the zero-g adjustment pin and
VS/2 is reduced by a factor of 6 by the internal resistor divider.
This is then gained by the factor of 3 in the output stage for a
total gain of 0.5 for the zero-g adjustment. (Note: The ratio of
the resistors in the divider is consistent from part-to-part; how-
ever, the absolute values can have a ±30% tolerance). The
zero-g adjustment voltage can be set up by a variety of methods
including a potentiometer (as shown in Figure 2), a PWM sig-
nal, or with a simple three-state output.
For a range of +75 g to –125 g the offset required is –25 g.
–25 g at 18 mV/g = 450 mV of offset is required.
Rearranging the offset equations above:
R = [(7.5 × VS)/offset] –30 = 53.3 kΩ connected to ground.
For asymmetric operation the g range midpoint may be shifted
up to ±80 g typically.
The simplest way is by adding a resistor between the ZERO g
ADJUST pin and VS or ground. The output will be offset by:
250k⍀
ZERO g
P1
ADJUST
Offset (V) = (7.5 × VS)/(30 + R)
where R is in kΩ and connected to VS.
Offset (V) = (–7.5 × VS)/(30 + R)
MICROCONTROLLER
500k⍀
ADXL190
P0
Figure 3. An Offset Adjustment Scheme
where R is in kΩ and connected to ground.
Resistors may also be connected to microcontroller I/O pins as
shown in Figure 3. Using two I/Os that may be set to VS, ground,
or three-state, there are seven possibilities as shown in Table I
(one cannot set one I/O pin to VS and the other to ground).
Using such a system, any ADXL190 may be user trimmed to
output 2.5 V ± 35 mV at zero g.
–4–
REV. 0
ADXL190
OUTLINE DIMENSIONS
Dimensions shown in inches and (mm).
14-Lead Cerpak
(QC-14)
0.485 (12.319)
MAX
8
14
0.291 (7.391)
0.285 (7.239)
0.419 (10.643)
0.394 (10.008)
1
7
0.345 (8.763)
0.290 (7.366)
PIN 1
0.300 (7.62)
0.195 (4.953)
0.115 (2.921)
0.215 (5.461)
0.119 (3.023)
8
0
0.020 (0.508)
0.004 (0.102)
SEATING
PLANE
0.050 0.020 (0.508)
0.013 (0.318)
0.009 (0.229)
0.050 (1.270)
0.016 (0.406)
(1.27)
BSC
0.013 (0.330)
REV. 0
–5–
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ADI
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