DL200 Datasheet, PDF (88/670 Pages) Motorola, Inc – Sensor

MMA2202D
Pin No.
1 thru 3
Pin Name
—
4
ST
5
6
7
8
9 thru 13
VOUT
STATUS
VSS
VDD
Trim pins
14 thru 16
—
Freescale Semiconductor, Inc.
Description
No internal connection. Leave
unconnected.
Logic input pin used to initiate
self–test.
Output voltage of the accelerome-
ter.
Logic output pin to indicate fault.
The power supply ground.
The power supply input.
Used for factory trim. Leave
unconnected.
No internal connection. Leave
unconnected.
PCB Layout
STATUS
P1
ST
P0
VOUT
VSS
VDD
R
A/D IN
1 kΩ C 0.01 µF
C 0.1 µF
VRH
C _{0.1 µF}
POWER SUPPLY
VSS
C 0.1 µF
VDD
VDD
LOGIC
INPUT
C1
0.1 µF
MMA2202D
6
4 ST
R1
8 VDD
VOUT ^{5 1 kΩ}
7 VSS
C2
0.01 µF
STATUS
OUTPUT
SIGNAL
Figure 4. SOIC Accelerometer with Recommended
Connection Diagram
Figure 5. Recommend PCB Layout for Interfacing
Accelerometer to Microcontroller
NOTES:
• Use a 0.1 µF capacitor on VDD to decouple the power
source.
• Physical coupling distance of the accelerometer to the
microcontroller should be minimal.
• Place a ground plane beneath the accelerometer to reduce
noise, the ground plane should be attached to all of the
open ended terminals shown in Figure 4.
• Use an RC filter of 1 kΩ and 0.01 µF on the output of the
accelerometer to minimize clock noise (from the switched
capacitor filter circuit).
• PCB layout of power and ground should not couple power
supply noise.
• Accelerometer and microcontroller should not be a high
current path.
• A/D sampling rate and any external power supply switching
frequency should be selected such that they do not inter-
fere with the internal accelerometer sampling frequency.
This will prevent aliasing errors.
2–52
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