MMA8491Q
Sensors
Freescale Semiconductor, Inc. 5
1.4 Pin descriptions
MMA8491Q is hosted in a 12-pin 3 mm x 3 mm QFN package. Ten pins are used for functions; two pins are unconnected. Refer
to Tab le 1 for complete pin descriptions and functions.
Figure 4. Pin connections (top view)
Table 1. Pin descriptions
Pin # Pin Name Function Description Pin Status
1Byp
Internal regulator output
capacitor connection
The internal regulator voltage of 1.8V is present on this pin. Connect to
external 0.1 μF bypass capacitor.
Output
2V
DD
Power Supply
Device power is supplied through the V
DD
line. Power supply
decoupling capacitors should be placed as near as possible to pin 1 of
the device.
Input
3SDA
I
2
C Data
I
2
C Slave Data Line
•7-bit I
2
C device address is 0x55.
• The SDA and SCL I2C connections are open drain, and therefore
usually require a pullup resistor
Input/Output
4EN
Enable Pin
The Enable pin fully turns on the accelerometer system when it is
pulled up to logic high. The accelerometer system is turned off when
the Enable pin is logic low.
Input
5SCL
I
2
C Clock I
2
C Slave Clock Line
Input
6Gnd
Ground
Ground
7Gnd
Ground
Ground
8 Zout
Push-pull Z-Axis Tilt Detection
Output
• Output is high when acceleration is > 0.688g (axis is |φ| > 45°).
• Output is low when acceleration is ≤ 0.688g (axis is |φ| ≤ 45°).
These pins are push-pull.
Output
9 Yout
Push-pull Y-Axis Tilt Detection
Output
Output
10 Xout
Push-pull X-Axis Tilt Detection
Output
Output
11 NC
No internal connection
12 NC
No internal connection
1
2
3
4
10
9
8
7
Xout
You t
Zout
Gnd
Byp
V
DD
SDA
EN
56
12 11
SCL
Gnd
NC
NC
