ANALOG DEVICES ADXL202EB Service Manual

6/15/00 4:00PM

Dual Axis Accelerometer

a

GENERAL DESCRIPTION

The ADXL202EB is a simple evaluation board that allows the
user to quickly evaluate the performance of the ADXL202 dual
axis ± 2 g accelerometer. Only three additional through-hole
passive components must be added, depending on the bandwidth
required in your application. The ADXL202EB has a 5-pin

0.1-inch spaced header for access to all power and signal lines
that may be attached to a prototyping board (breadboard) or wired
via a standard plug. Two holes are provided for mechanical
attachment of the ADXL202EB to your application.

CIRCUIT DESCRIPTION

The schematic and parts list of the ADXL202EB are shown in
Figure 1 and Table I respectively. The minimal application will
require at least one resistor (R
PWM period (T2). Analog bandwidth may be set by adding
capacitors C2 and C3. Refer to the ADXL202 data sheet for a
complete description of the operation of the accelerometer.

The part layout of the ADXL202EB is shown in Figure 2. The
ADXL202EB has two factory- installed 2200 pF capacitors (C1
and C4) at X

FILT

and Y

FILT

specification of the ADXL202. Your application will likely require
narrower bandwidth (and lower noise), in which case a through­hole capacitor may be added 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 pinout descrip­tion of the ADXL202EB is shown in Table II.

) added to the board to set the

SET

to satisfy the minimum filter capacitor

Evaluation Board

ADXL202EB

ADXL202EB

C5

0.47␮F

R

SET

ADDED

BY

USER

Figure 1. ADXL202EB Schematic

1

ADDED

USER

C3

BY

2200pF

C4

C1
2200pF

V

A

DD

X

D

OUT

Y

C

OUT

E

COM

ST

B

C2
ADDED
BY
USER

SETTING THE PERIOD OF THE DUTY CYCLE
MODULATOR

The DCM period is set by R
and 2 M⍀. See Table III for some typical R

. Choose a value between 100 k⍀

SET

SET

values.

REV. 0

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reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
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Fax: [phone] © Analog Devices, Inc., 2000

6/15/00 4:00PM

ADV611/ADV612

Table I. ADXL202EB Parts List

Reference Value Function

C1 2200 pF/25V X
C2 Added by User X
C3 Added by User Y
C4 2200 pF/25V Y
J1 Connector All power and signal connection through J1
R1 Added by User R
U1 ADXL202 Dual axis ± 2g accelerometer

. Sets X axis analog bandwidth along with C2

FILT

. Sets X axis analog bandwidth along with C1

FILT

. Sets Y axis analog bandwidth along with C4

FILT

. Sets Y axis analog bandwidth along with C3

FILT

. Sets the PWM period (T2)

SET

Table II. ADXL202EB Pinout Description

Pin Reference Pinout

E GROUND
B SELF-TEST INPUT
D X AXIS DUTY CYCLE OUT
C Y AXIS DUTY CYCLE OUT
A +V SUPPLY (3 to 5.25 VDC)

Table III. DCM Period vs. R

T2 Period R

SET

SET

Value

1 ms 124 k⍀
2 ms 248 k⍀
5 ms 620 k⍀
10 ms 1.24 M⍀

Table IV. Typical X

FILT

and Y

Values vs. Bandwidth and

FILT

Noise Performance

X

FILT

, Y

FILT

Bandwidth RMS Noise

0.01 ␮F 500 Hz 12.7 mg

0.047 ␮F 100 Hz 7 mg

0.1 ␮F 50 Hz 4.2 mg

0.47 ␮F 10 Hz 2.3 mg

C5

R

SET

U1

C1

C2

C4

C3

J1

ACEBD

Figure 2. ADXL202EB Part Layout (Top View)

SPECIAL NOTES ON HANDLING

Note that the ADXL202EB is not reverse polarity protected.
Reversing the +V

and Ground pins will damage the

SUPPLY

ADXL202.

Dropping the ADXL202EB on a hard surface may generate
several thousand g of acceleration. Enough to damage the accel­erometer. Please refer to the ADXL202 data sheet for information
on shock survivability.

C01939–0-6/00 (rev. 0)

SETTING THE ADXL202’S BANDWIDTH

The ADXL202EB is supplied with the minimum specified X
and Y

values installed. Your application will likely require a

FILT

FILT

narrower bandwidth to improve noise performance. See Table
IV for some typical capacitor values.

–2–

PRINTED IN U.S.A.

REV. 0