Evaluation Board User Guide
UG-315
One Technology Way • P.O. Box 9106 • Norwood, MA 02062-9106, U.S.A. • Tel: 781.329.4700 • Fax: 781.461.3113 • www.analog.com
Evaluating the ±2 g, Dual Axis, PWM Output Accelerometer
GENERAL DESCRIPTION
SPECIAL NOTES ON HANDLING
The EVAL-ADXL212Z is a simple evaluation board that allows
quick evaluation of the performance of the ADXL212 dual
axis ±2 g accelerometer with PWM outputs. The user needs to
add only three additional through-hole passive components,
depending on the bandwidth required in the application. The
EVAL-ADXL212Z has a 5-pin, 0.1 inch-spaced header for
access to all power and signal lines that the user can attach to
a prototyping board (breadboard) or wire using a standard
plug. Two holes are provided for mechanical attachment of
the EVAL-ADXL212Z to the application.
Note that the EVAL-ADXL212Z is not reverse polarity protected. Reversing the power supply or applying inappropriate
voltages to any pin (outside the absolute maximum ratings
listed in the ADXL212 data sheet) may damage the EVALADXL212Z.
Dropping the EVAL-ADXL212Z on a hard surface can generate
several thousand g of acceleration, enough to damage the accelerometer. See the ADXL212 data sheet for information on shock
survivability.
CIRCUIT DESCRIPTION
SCHEMATICS, LAYOUT, AND PARTS LIST
PIN 1
The layout of the EVAL-ADXL212Z evaluation board is shown
in Figure 2. The EVAL-ADXL212Z has two factory-installed
2200 pF capacitors (C1 and C4) at XFILT and YFILT to satisfy the
minimum filter capacitor specification for the ADXL212. Many
applications require a narrower bandwidth (and lower noise), in
which case the user can add a through-hole capacitor in parallel
in the space provided at C2 and C3, respectively. When
calculating the capacitance required to achieve the desired
analog bandwidth, do not forget to subtract the 2200 pF already
on the PCB.
The pin function descriptions for the EVAL-ADXL212Z are
listed in Table 2.
ADXL212
RSET
ADDED
BY USER
C3
ADDED
BY USER
C5
0.47µF
A
VDD
D
XOUT
C
YOUT
E
COMMON
B
ST
C2
ADDED
BY USER
C4
C1
2200pF 2200pF
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The schematic and parts list of the EVAL-ADXL212Z are shown
in Figure 1 and Table 1, respectively. The minimal application
circuit requires at least one resistor (RSET) added to the board
to set the PWM period (T2). Analog bandwidth can be set by
adding Capacitors C2 and C3. See the ADXL212 data sheet for
a complete description of the operation of the accelerometer.
Figure 1. EVAL-ADXL212Z Schematic
C5
C1
C2
U1
RSET
SETTING THE PERIOD OF THE DUTY CYCLE
MODULATOR
C4
The DCM period is set by RSET. Choose a value between
100 kΩ and 2 MΩ. See Table 3 for typical RSET values.
C3
E
B
D
C
A
Figure 2. EVAL-ADXL212Z Board Layout
PLEASE SEE THE LAST PAGE FOR AN IMPORTANT
WARNING AND LEGAL TERMS AND CONDITIONS.
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Evaluation Board User Guide
Table 1. EVAL-ADXL212Z Parts List
Table 2. EVAL-ADXL212Z Pin Function Descriptions
Reference
C1
Value
2200 pF/25 V
C2
Added by user
C3
Added by user
Pin Reference
E
B
D
C
A
C4
2200 pF/25 V
J1
Connector
R1
U1
Added by user
ADXL212
Function
XFILT. Sets X axis analog
bandwidth along with C2.
XFILT. Sets X axis analog
bandwidth along with C1.
YFILT. Sets Y axis analog
bandwidth along with C4.
YFILT. Sets Y axis analog
bandwidth along with C3.
All power and signal connection
through J1.
RSET. Sets the PWM period (T2).
Dual axis ±2 g accelerometer.
Function
Ground
Self-test input
X-axis duty cycle out
Y-axis duty cycle out
+V supply (3 VDC to 5.25 VDC)
Table 3. DCM Period vs. RSET Value
T2 Period
1 ms
2 ms
5 ms
10 ms
RSET
124 kΩ
248 kΩ
620 kΩ
1.24 MΩ
ESD Caution
ESD (electrostatic discharge) sensitive device. Charged devices and circuit boards can discharge without detection. Although this product features patented or proprietary protection
circuitry, damage may occur on devices subjected to high energy ESD. Therefore, proper ESD precautions should be taken to avoid performance degradation or loss of functionality.
Legal Terms and Conditions
By using the evaluation board discussed herein (together with any tools, components documentation or support materials, the “Evaluation Board”), you are agreeing to be bound by the terms and conditions
set forth below (“Agreement”) unless you have purchased the Evaluation Board, in which case the Analog Devices Standard Terms and Conditions of Sale shall govern. Do not use the Evaluation Board until you
have read and agreed to the Agreement. Your use of the Evaluation Board shall signify your acceptance of the Agreement. This Agreement is made by and between you (“Customer”) and Analog Devices, Inc.
(“ADI”), with its principal place of business at One Technology Way, Norwood, MA 02062, USA. Subject to the terms and conditions of the Agreement, ADI hereby grants to Customer a free, limited, personal,
temporary, non-exclusive, non-sublicensable, non-transferable license to use the Evaluation Board FOR EVALUATION PURPOSES ONLY. Customer understands and agrees that the Evaluation Board is provided
for the sole and exclusive purpose referenced above, and agrees not to use the Evaluation Board for any other purpose. Furthermore, the license granted is expressly made subject to the following additional
limitations: Customer shall not (i) rent, lease, display, sell, transfer, assign, sublicense, or distribute the Evaluation Board; and (ii) permit any Third Party to access the Evaluation Board. As used herein, the term
“Third Party” includes any entity other than ADI, Customer, their employees, affiliates and in-house consultants. The Evaluation Board is NOT sold to Customer; all rights not expressly granted herein, including
ownership of the Evaluation Board, are reserved by ADI. CONFIDENTIALITY. This Agreement and the Evaluation Board shall all be considered the confidential and proprietary information of ADI. Customer may
not disclose or transfer any portion of the Evaluation Board to any other party for any reason. Upon discontinuation of use of the Evaluation Board or termination of this Agreement, Customer agrees to
promptly return the Evaluation Board to ADI. ADDITIONAL RESTRICTIONS. Customer may not disassemble, decompile or reverse engineer chips on the Evaluation Board. Customer shall inform ADI of any
occurred damages or any modifications or alterations it makes to the Evaluation Board, including but not limited to soldering or any other activity that affects the material content of the Evaluation Board.
Modifications to the Evaluation Board must comply with applicable law, including but not limited to the RoHS Directive. TERMINATION. ADI may terminate this Agreement at any time upon giving written notice
to Customer. Customer agrees to return to ADI the Evaluation Board at that time. LIMITATION OF LIABILITY. THE EVALUATION BOARD PROVIDED HEREUNDER IS PROVIDED “AS IS” AND ADI MAKES NO
WARRANTIES OR REPRESENTATIONS OF ANY KIND WITH RESPECT TO IT. ADI SPECIFICALLY DISCLAIMS ANY REPRESENTATIONS, ENDORSEMENTS, GUARANTEES, OR WARRANTIES, EXPRESS OR IMPLIED, RELATED
TO THE EVALUATION BOARD INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTY OF MERCHANTABILITY, TITLE, FITNESS FOR A PARTICULAR PURPOSE OR NONINFRINGEMENT OF INTELLECTUAL
PROPERTY RIGHTS. IN NO EVENT WILL ADI AND ITS LICENSORS BE LIABLE FOR ANY INCIDENTAL, SPECIAL, INDIRECT, OR CONSEQUENTIAL DAMAGES RESULTING FROM CUSTOMER’S POSSESSION OR USE OF
THE EVALUATION BOARD, INCLUDING BUT NOT LIMITED TO LOST PROFITS, DELAY COSTS, LABOR COSTS OR LOSS OF GOODWILL. ADI’S TOTAL LIABILITY FROM ANY AND ALL CAUSES SHALL BE LIMITED TO THE
AMOUNT OF ONE HUNDRED US DOLLARS ($100.00). EXPORT. Customer agrees that it will not directly or indirectly export the Evaluation Board to another country, and that it will comply with all applicable
United States federal laws and regulations relating to exports. GOVERNING LAW. This Agreement shall be governed by and construed in accordance with the substantive laws of the Commonwealth of
Massachusetts (excluding conflict of law rules). Any legal action regarding this Agreement will be heard in the state or federal courts having jurisdiction in Suffolk County, Massachusetts, and Customer hereby
submits to the personal jurisdiction and venue of such courts. The United Nations Convention on Contracts for the International Sale of Goods shall not apply to this Agreement and is expressly disclaimed.
©2011 Analog Devices, Inc. All rights reserved. Trademarks and
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