Zakładka z wyszukiwarką danych komponentów
Selected language     Polish  ▼
Nazwa części
         Szczegóły


ADXL316WBCSZ-RL Datasheet(Arkusz danych) 11 Page - Analog Devices

Numer części ADXL316WBCSZ-RL
Szczegółowy opis  Small, Low Power, 3-Axis plus minus16 g Accelerometer
Pobierz  14 Pages
Scroll/Zoom Zoom In 100% Zoom Out
Producent  AD [Analog Devices]
Strona internetowa  http://www.analog.com
Logo 

 
 11 page
background image
Data Sheet
ADXL316
Rev. 0 | Page 11 of 14
APPLICATIONS INFORMATION
POWER SUPPLY DECOUPLING
For most applications, a single 0.1 µF capacitor, CDC, placed
close to the ADXL316 supply pins adequately decouples the
accelerometer from noise on the power supply. However, in
applications where noise is present at the 50 kHz internal clock
frequency (or any harmonic thereof), additional care in power
supply bypassing is required because this noise can cause errors
in acceleration measurement. If additional decoupling is needed,
a 100 Ω (or smaller) resistor or a ferrite bead can be inserted in
the supply line. Additionally, a larger bulk bypass capacitor
(1 µF or greater) can be added in parallel to CDC. Ensure that
the connection from the ADXL316 ground to the power supply
ground is low impedance, because noise transmitted through
ground has a similar effect as noise transmitted through VS.
SETTING THE BANDWIDTH USING CX, CY, AND CZ
The ADXL316 has provisions for band-limiting the XOUT, YOUT,
and ZOUT pins. Capacitors must be added at these pins to
implement low-pass filtering for antialiasing and noise
reduction. The equation for the −3 dB bandwidth is
f−3dB = 1/(2π(32 kΩ) × C(X,Y, Z))
or more simply
f–3dB = 5 µF/C(X,Y, Z)
The tolerance of the internal resistor (RFILT) can vary by as much
as ±15% of its nominal value (32 kΩ), and the bandwidth varies
accordingly. A minimum capacitance of 0.0047 µF for CX, CY,
and CZ is recommended in all cases.
Table 4. Filter Capacitor Selection, CX, CY, and CZ
Bandwidth (Hz)
Capacitor (µF)
1
4.7
10
0.47
50
0.10
100
0.05
200
0.027
500
0.01
SELF TEST
The ST pin controls the self test feature. When this pin is connected
to VS, an electrostatic force is exerted on the accelerometer beam.
The resulting movement of the beam allows the user to test if
the accelerometer is functional. The typical change in output is
−0.88 g (corresponding to −50 mV) on the x-axis, 0.88 g (or
+50 mV) on the y-axis, and 1.58 g (or +90 mV) on the z-axis.
The ST pin may be left open circuit or connected to the common
pin (COM) in normal use.
Never expose the ST pin to voltages greater than VS + 0.3 V. If
this cannot be guaranteed due to the system design (for instance,
if there are multiple supply voltages), a low VF clamping diode
between ST and VS is recommended.
DESIGN TRADE-OFFS FOR SELECTING FILTER
CHARACTERISTICS: THE NOISE/BW TRADE-OFF
The selected accelerometer bandwidth ultimately determines
the measurement resolution (the smallest detectable acceleration).
Filtering can lower the noise floor to improve the resolution of
the accelerometer. Resolution is dependent on the analog filter
bandwidth at XOUT, YOUT, and ZOUT.
The output of the ADXL316 has a typical bandwidth of greater
than 500 Hz. The user must filter the signal at this point to limit
aliasing errors. The analog bandwidth must be no more than
half the analog-to-digital sampling frequency to minimize
aliasing. The analog bandwidth can decrease further to reduce
noise and improve resolution.
The ADXL316 has white Gaussian noise, which contributes
equally at all frequencies and is described in terms of µg/√Hz
(the noise is proportional to the square root of the accelerometer
bandwidth). Limit bandwidth to the lowest frequency needed
by the application to maximize the resolution and dynamic
range of the accelerometer.
With the single-pole roll-off characteristic, the typical rms noise
of the ADXL316 is determined by
)
1.6
(
×
×
=
BW
Density
Noise
Noise
RMS
Often, the peak value of the noise is desired. Statistical methods
can only estimate peak-to-peak noise. Table 5 is useful for
estimating the probabilities of exceeding various peak values,
given the rms value.
Table 5. Estimation of Peak-to-Peak Noise
Peak-to-Peak Value
% of Time that Noise Exceeds
Nominal Peak-to-Peak Value
2 × rms
32
4 × rms
4.6
6 × rms
0.27
8 × rms
0.006




Html Pages

1  2  3  4  5  6  7  8  9  10  11  12  13  14 


Datasheet Download




Link URL

Czy Alldatasheet okazała się pomocna?  [ DONATE ]  

O Alldatasheet   |   Reklama   |   Kontakt   |   Polityka prywatności   |   Dodaj do ulubionych   |   Linki   |   Lista producentów
All Rights Reserved© Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  , Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp  |   Russian : Alldatasheetru.com
Korean : Alldatasheet.co.kr   |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com  |   Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl