ADXL202AQC ,Low Cost +-2 g/+-10 g Dual Axis iMEMS Accelerometers with Digital OutputSpecifications subject to change without notice.REV. B–2–ADXL202/ADXL210PIN CONFIGURATIONABSOLUTE M ..
ADXL202JE ,Low-Cost +-2 g Dual-Axis Accelerometer with Duty Cycle OutputSpecifications subject to change without notice.–2– REV. AADXL202EABSOLUTE MAXIMUM RATINGS* PIN CON ..
ADXL202JQC ,Low Cost +-2 g/+-10 g Dual Axis iMEMS Accelerometers with Digital OutputSpecifications subject to change without notice.REV. B–2–ADXL202/ADXL210PIN CONFIGURATIONABSOLUTE M ..
ADXL202JQC. ,Low Cost +-2 g/+-10 g Dual Axis iMEMS Accelerometers with Digital OutputSPECIFICATIONSR = 125 kV, Acceleration = 0 g, unless otherwise noted)SET ADXL202/JQC/AQC ADXL21 ..
ADXL202JQC-1 ,±2 g Dual Axis AccelerometerSPECIFICATIONS Acceleration = 0 g, unless otherwise noted.)1TPC ADXL202JE ADXL202 ..
ADXL203CE ,High Precision, ±1.5g, Dual Axis AccelerometerSpecifications subject to change without notice. No license is granted by implication www.analog.c ..
AM2833DC , 1024-Bit Static Shift Registers
AM2841ADC ,64 x 4 BITS FIRST-IN FIRST-OUT MEMORIESAm3341/ 2841/ 2841A
Distinctive Characteristics
. "Plug- In" replacement for Fairchild 3341
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AM2841DC ,64 x 4 BITS FIRST-IN FIRST-OUT MEMORIESAm3341/ 2841/ 2841A
Distinctive Characteristics
. "Plug- In" replacement for Fairchild 3341
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AM2841PC ,64 x 4 BITS FIRST-IN FIRST-OUT MEMORIESBLOCK DIAGRAM
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AM2841PC ,64 x 4 BITS FIRST-IN FIRST-OUT MEMORIESFUNCTIONAL DESCRIPTION
Parallel expansion to wider words only requires that rows of FIFOs
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AM28F010-120EI , 1 Megabit (128 K x 8-Bit) CMOS 12.0 Volt, Bulk Erase Flash Memory
ADXL202AQC-ADXL202JQC-ADXL202JQC.-ADXL210AQC-ADXL210JQC
Low Cost +-2 g/+-10 g Dual Axis iMEMS Accelerometers with Digital Output
REV.B
Low Cost 62 g/610 g Dual Axis
iMEMS® Accelerometers
with Digital Output
FEATURES
2-Axis Acceleration Sensor on a Single IC Chip
Measures Static Acceleration as Well as Dynamic
Acceleration
Duty Cycle Output with User Adjustable Period
Low Power <0.6 mA
Faster Response than Electrolytic, Mercury or Thermal
Tilt Sensors
Bandwidth Adjustment with a Single Capacitor Per Axis
5 mg Resolution at 60 Hz Bandwidth
+3 V to +5.25 V Single Supply Operation
1000 g Shock Survival
APPLICATIONS
2-Axis Tilt Sensing
Computer Peripherals
Inertial Navigation
Seismic Monitoring
Vehicle Security Systems
Battery Powered Motion Sensing
FUNCTIONAL BLOCK DIAGRAM
CDC
A(g) = (T1/T2 – 0.5)/12.5%
0g = 50% DUTY CYCLE
T2 = RSET/125MV
GENERAL DESCRIPTIONThe ADXL202/ADXL210 are low cost, low power, complete
2-axis accelerometers with a measurement range of either2 g/–10 g. The ADXL202/ADXL210 can measure both dy-
namic acceleration (e.g., vibration) and static acceleration (e.g.,
gravity).
The outputs are digital signals whose duty cycles (ratio of pulse-
width to period) are proportional to the acceleration in each of
the 2 sensitive axes. These outputs may be measured directly
with a microprocessor counter, requiring no A/D converter or
glue logic. The output period is adjustable from 0.5 ms to 10 ms
via a single resistor (RSET). If a voltage output is desired, a
voltage output proportional to acceleration is available from the
XFILT and YFILT pins, or may be reconstructed by filtering the
duty cycle outputs.
The bandwidth of the ADXL202/ADXL210 may be set from
0.01 Hz to 5 kHz via capacitors CX and CY. The typical noise
floor is 500 mg/√Hz allowing signals below 5 mg to be resolved
for bandwidths below 60 Hz.
The ADXL202/ADXL210 is available in a hermetic 14-lead
Surface Mount CERPAK, specified over the 0°C to +70°C
commercial or –40°C to +85°C industrial temperature range.
iMEMS is a registered trademark of Analog Devices, Inc.
ADXL202/ADXL210–SPECIFICATIONSNOTESFor all combinations of offset and sensitivity variation.Alignment error is specified as the angle between the true and indicated axis of sensitivity.Transverse sensitivity is the algebraic sum of the alignment and the inherent sensitivity errors.Specification refers to the maximum change in parameter from its initial at +25°C to its worst case value at TMIN to TMAX.Noise density (mg/√Hz) is the average noise at any frequency in the bandwidth of the part.CFILT in mF. Addition of filter capacitor will increase turn on time. Please see the Application section on power cycling.
All min and max specifications are guaranteed. Typical specifications are not tested or guaranteed.
Specifications subject to change without notice.
(TA = TMIN to TMAX, TA = +258C for J Grade only, VDD = +5 V,
RSET = 125 kV, Acceleration = 0 g, unless otherwise noted)
PIN FUNCTION DESCRIPTIONS
PACKAGE CHARACTERISTICS
ABSOLUTE MAXIMUM RATINGS*Acceleration (Any Axis, Unpowered for 0.5 ms) . . . . . .1000 g
Acceleration (Any Axis, Powered for 0.5 ms) . . . . . . . . .500 g
+VS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .–0.3 V to +7.0 V
Output Short Circuit Duration
(Any Pin to Common) . . . . . . . . . . . . . . . . . . . . . .Indefinite
Operating Temperature . . . . . . . . . . . . . . . . .–55°C to +125°C
Storage Temperature . . . . . . . . . . . . . . . . . . .–65°C to +150°C
*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.
CAUTIONESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000V readily
accumulate on the human body and test equipment and can discharge without detection.
Although the ADXL202/ADXL210 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.
Drops onto hard surfaces can cause shocks of greater than 1000 g
and exceed the absolute maximum rating of the device. Care
should be exercised in handling to avoid damage.
PIN CONFIGURATIONFigure 1 shows the response of the ADXL202 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. The ADXL210 reacts similarly with out-
put changes appropriate to its scale.
Figure 1.ADXL202/ADXL210 Nominal Response Due to
Gravity
ORDERING GUIDEADXL202AQC
ADXL210JQC
ADXL202/ADXL210
TEMPERATURE – 8C
PERIOD NORMALIZED TO 1 AT 25
0.96Figure 2.Normalized DCM Period (T2) vs. Temperature
TEMPERATURE – 8C
ZERO
OFFSET SHIFT IN
0.2Figure 3.Typical Zero g Offset vs. Temperature
TEMPERATURE – 8C
SUPPLY CURRENT – mA20406080
(@ +258C RSET = 125 kV, VDD = +5 V, unless otherwise noted)TYPICAL CHARACTERISTICSFigure 5.Typical X Axis Sensitivity Drift Due to
Temperature
Figure 6.Typical Turn-On Time
DUTY CYCLE OUTPUT – % per g
PERCENTAGE OF SAMPLESFigure 8.Typical Sensitivity per g at +25°C
CX, CY
BANDWIDTH
0.01mF
500Hz
0.47mF
10Hz
0.047mF
100Hz
TOTAL RMS NOISE – m
0.1mF
50HzFigure 9.Typical Noise at XFILT Output
Figure 10.Typical Noise at Digital Outputs
Figure 11.Rotational Die Alignment
ADXL202/ADXL210
DEFINITIONSLength of the “on” portion of the cycle.Length of the total cycle.
Duty CycleRatio of the “on” time (T1) of the cycle to the total
cycle (T2). Defined as T1/T2 for the ADXL202/
ADXL210.
PulsewidthTime period of the “on” pulse. Defined as T1 for
the ADXL202/ADXL210.
THEORY OF OPERATIONThe ADXL202/ADXL210 are complete dual axis acceleration
measurement systems on a single monolithic IC. They contain a
polysilicon surface-micromachined sensor and signal condition-
ing circuitry to implement an open loop acceleration measure-
ment architecture. For each axis, an output circuit converts the
analog signal to a duty cycle modulated (DCM) digital signal
that can be decoded with a counter/timer port on a micropro-
cessor. The ADXL202/ADXL210 are capable of measuring
both positive and negative accelerations to a maximum level of2 g or –10 g. The accelerometer measures static acceleration
forces such as gravity, allowing it to be used as a tilt sensor.
The sensor is a surface micromachined polysilicon structure
built on top of the silicon wafer. Polysilicon springs suspend the
structure over the surface of the wafer and provide a resistance
against acceleration forces. Deflection of the structure is mea-
sured using a differential capacitor that consists of independent
fixed plates and central plates attached to the moving mass. The
fixed plates are driven by 180° out of phase square waves. An
acceleration will deflect the beam and unbalance the differential
capacitor, resulting in an output square wave whose amplitude
is proportional to acceleration. Phase sensitive demodulation
techniques are then used to rectify the signal and determine the
direction of the acceleration.
The output of the demodulator drives a duty cycle modulator
(DCM) stage through a 32 kW resistor. At this point a pin is
available on each channel to allow the user to set the signal
bandwidth of the device by adding a capacitor. This filtering
improves measurement resolution and helps prevent aliasing.
After being low-pass filtered, the analog signal is converted to a
duty cycle modulated signal by the DCM stage. A single resistor
sets the period for a complete cycle (T2), which can be set be-
tween 0.5 ms and 10 ms (see Figure 12). A 0 g acceleration
produces a nominally 50% duty cycle. The acceleration signal
can be determined by measuring the length of the T1 and T2
pulses with a counter/timer or with a polling loop using a low
cost microcontroller.
An analog output voltage can be obtained either by buffering the
signal from the XFILT and YFILT pin, or by passing the duty cycle
signal through an RC filter to reconstruct the dc value.
The ADXL202/ADXL210 will operate with supply voltages as
low as 3.0 V or as high as 5.25 V.
APPLICATIONS
POWER SUPPLY DECOUPLINGFor most applications a single 0.1 mF capacitor, CDC, will ad-
equately decouple the accelerometer from signal and noise on
the power supply. However, in some cases, especially where digital
devices such as microcontrollers share the same power supply, digi-
tal noise on the supply may cause interference on the ADXL202/
ADXL210 output. This is often observed as a slowly undulating
fluctuation of voltage at XFILT and YFILT. If additional decou-
pling is needed, a 100 W (or smaller) resistor or ferrite beads,
may be inserted in the ADXL202/ADXL210’s supply line.
DESIGN PROCEDURE FOR THE ADXL202/ADXL210The design procedure for using the ADXL202/ADXL210 with a
duty cycle output involves selecting a duty cycle period and a
filter capacitor. A proper design will take into account the appli-
cation requirements for bandwidth, signal resolution and acqui-
sition time, as discussed in the following sections.
VDDThe ADXL202/ADXL210 have two power supply (VDD) Pins:
13 and 14. These two pins should be connected directly together.
COMThe ADXL202/ADXL210 have two commons, Pins 4 and 7.
These two pins should be connected directly together and Pin 7
grounded.
VTPThis pin is to be left open; make no connections of any kind to
this pin.
Decoupling Capacitor CDCA 0.1 mF capacitor is recommended from VDD to COM for
power supply decoupling.
The ST pin controls the self-test feature. When this pin is set to
VDD, an electrostatic force is exerted on the beam of the acceler-
ometer. The resulting movement of the beam allows the user to
test if the accelerometer is functional. The typical change in
output will be 10% at the duty cycle outputs (corresponding to
800 mg). This pin may be left open circuit or connected to
common in normal use.
Duty Cycle DecodingThe ADXL202/ADXL210’s digital output is a duty cycle modu-
lator. Acceleration is proportional to the ratio T1/T2. The
nominal output of the ADXL202 is:
0 g = 50% Duty Cycle
Scale factor is 12.5% Duty Cycle Change per g
The nominal output of the ADXL210 is:
0 g = 50% Duty Cycle
Scale factor is 4% Duty Cycle Change per g
These nominal values are affected by the initial tolerance of the
device including zero g offset error and sensitivity error.
T2 does not have to be measured for every measurement cycle.
It need only be updated to account for changes due to tempera-
ture, (a relatively slow process). Since the T2 time period is
