Silicon Designs, Inc.

Model 2420

Triaxial Digital Accelerometer Module

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2420 AccelerometerFEATURES

DESCRIPTION

The Model 2420 is a triaxial accelerometer module which is meant to be used with the Model 3320 G-LoggerTM Acceleration Acquisition System. The 2420 contains three orthogonally mounted Model 1010 integrated accelerometers which feature a miniature, hermetically sealed, micromachined capacitive sense element, a custom integrated circuit sense amplifier and a sigma-delta A/D converter. It provides a TTL/CMOS compatible output signal for measuring accelerations in commercial or industrial environments and is tailored for zero to medium frequency instrumentation applications. It is relatively insensitive to temperature changes and gradients and its frequency response includes DC. The case is rugged anodized aluminum and is easily mounted via two #6 screws. Refer to Silicon Design’s Model 1010 data sheet for detailed descriptions of the CLK and CNT signals.

 ORDERING INFORMATION
Full Scale
Acceleration		 Model
Number

±5 G

2420-005

±10 G

2420-010

±25 G

2420-025

±50 G

2420-050

±100 G

2420-100

±200 G

2420-200

OPERATION

The Model 2420 produces three digital pulse train outputs in which the density of pulses (number of pulses per second) is proportional to applied acceleration. It operates with a single +5 volt power supply and requires a clock of 100kHz-1MHz. Each of the three outputs are ratiometric to the clock frequency and independent of the power supply voltage. The "Z" axis is perpendicular to the bottom of the package, with positive acceleration defined as a force pushing on the bottom of the package. The "X" and "Y" axis directions are marked on the cover with positive acceleration defined as acceleration in the direction of the axis arrow. External digital line drivers can be used to drive long cables or when used in an electrically noisy environment.

SIGNALS (see 1010 data sheet for signal descriptions)

+5V: (pin 5) DC Power (reddish brown wire)
GND: (pins 6-9) Ground (black wire)
CLK: (pin 1) Input reference clock; 100Khz-1MHz (white wire)
CNTX: (pin 2) X-Axis count output (green wire)
CNTY: (pin 4) Y-Axis count output (light brown wire)
CNTZ: (pin 3) Z-Axis count output (light blue wire)

 

ABSOLUTE MAXIMUM RATINGS *

Case Operating Temperature ................. -55 to +125°C
Storage Temperature ............................ -55 to +125°C
Acceleration Over-range ................... 2000g for 0.1 ms
Voltage on VDD to GND .......................... -0.5V to 6.5V
Voltage on Any Pin to GND 1........... -0.5V to VDD+0.5V
Power Dissipation ......................................... 100 mW
 

* NOTICE: Stresses above those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only. Functional operation of the device at or above these conditions is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.

PERFORMANCE - By Model: VDD=5.0VDC, TC=25°C.
Model Number 2420-005 2420-010 2420-025 2420-050 2420-100 2420-200 Units
Input Range ± 5 ± 10 ± 25 ± 50 ± 100 ± 200 G
Frequency Response (nominal, 3dB) 0 - 600 0 - 1000 0 - 1600 0 -2000 0 - 2500 0 - 2500 Hz
Sensitivity (FCLK = 1 MHz) .01 .02 .05 .10 .20 .40 mG/pulse/sec
Max. Mechanical Shock (0.1 ms) 2000 G

PERFORMANCE - All Models: Unless otherwise specified VDD=5.0VDC, FCLK=250kHz, TC=25°C.
Parameter Min Typ Max Units
Cross Axis Sensitivity   2 3 %
Bias Calibration Error 2   1 2  % of FCLK (span)
Bias Temperature Shift (TC= -55 to +125°C) 2   100 300  (ppm of FCLK)/°C
Scale Factor Calibration Error 2,3   1 2 %
Scale Factor Temperature Shift (TC= -55 to 125°C) 2   +300   ppm/°C
Non-Linearity (-90% to +90% of Full Scale) 3   0.5 1.0 % of span
Power Supply Rejection Ratio 40     dB
Operating Voltage (VS) 4.5 5 5.5 V
Operating Current 2   6.0 9.0 mA
Clock Input Voltage Range (with Respect to GND) -.5   VDD+ 0.5 V
Mass (not including cable)   21   grams
Cable Mass   15   grams/meter
Notes:
  1. Voltages on the CLK & CNT signal wires may exceed 0.5 volt above or below the supply voltage provided the current into or out of the wire is limited to 1 mA.
  2. Tighter tolerances available on special order.
  3. 100g versions and above are tested from -65 to +65 g.

 

ALTERNATE OUTPUT VERSION AVAILABLE:   A custom version may be ordered which provides the DIR (direction) output instead of the CNT (count) output. For a description of the DIR signal, see the 1010 data sheet.

ESD CONSIDERATIONS: The model 2420 accelerometer is a CMOS device subject to damage by large electrostatic dischaarges. Diode protection is provided on the inputs and outputs but care should be exercised during handling of the connector or cable wire ends (without connector). Individuals and tools should be grounded before coming in contact with the connector pins or cable wire ends.

SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE