Document Number: MMA7361LC
Rev 0, 03/2010

Freescale Semiconductor
Technical Data

±1.5g, ±6g Three Axis Low-g
Micromachined Accelerometer

MMA7361LCThe MMA7361LC is a low power, low profile capacitive micromachined
accelerometer featuring signal conditioning, a 1-pole low pass filter,
temperature compensation, self test, 0g-Detect which detects linear freefall,and g-Select which allows for the selection between 2 sensitivities. Zero-g
offset and sensitivity are factory set and require no external devices. The
MMA7361LC includes a Sleep Mode that makes it ideal for handheld battery
powered electronics.

MMA7361LC: XYZ AXISACCELEROMETER±1.5g, ±6g

Features
3mm x 5mm x 1.0mm LGA-14 Package
Low Current Consumption: 400 μA
Sleep Mode: 3 μA
Low Voltage Operation: 2.2 V – 3.6 V
High Sensitivity (800 mV/g @ 1.5g)
Selectable Sensitivity (±1.5g, ±6g)
Fast Turn On Time (0.5 ms Enable Response Time)
Self Test for Freefall Detect Diagnosis
0g-Detect for Freefall Protection
Signal Conditioning with Low Pass Filter
Robust Design, High Shocks Survivability
RoHS Compliant
Environmentally Preferred Product
Low Cost

Bottom View

14 LEADLGACASE 1977-01

Typical Applications

Top View

VDD

13

1
2

12

N/C
g-Select0g-Detect
N/C

7

ORDERING INFORMATION

11

VSS

N/C

10

ZOUT

Self Test

9

YOUT

3

XOUT

4

N/C

14

N/C

5

3D Gaming: Tilt and Motion Sensing, Event Recorder
HDD MP3 Player: Freefall Detection
Laptop PC: Freefall Detection, Anti-Theft
Cell Phone: Image Stability, Text Scroll, Motion Dialing, E-Compass
Pedometer: Motion Sensing
PDA: Text Scroll
Navigation and Dead Reckoning: E-Compass Tilt Compensation
Robotics: Motion Sensing

6

•
•
•
•
•
•
•
•

8

•
•
•
•
•
•
•
•
•
•
•
•
•
•

Part Number

Temperature
Range

Package
Drawing

Package

Shipping

MMA7361LCT–40 to +85°C

1977-01

LGA-14

Tray

MMA7361LCR1–40 to +85°C

1977-01

LGA-147” Tape & Reel

MMA7361LCR2–40 to +85°C

1977-01

LGA-1413” Tape & Reel

© Freescale Semiconductor, Inc., 2010. All rights reserved.

Sleep
Figure 1. Pin Connections

VDD

0g-Detectg-Select

Sleep

G-CELLSENSOR

OSCILLATOR

CLOCK
GEN

X-TEMPCOMPXOUTC to VCONVERTERGAIN+
FILTER

Y-TEMPCOMP

YOUTZ-TEMPCOMPZOUTSELFTEST
Self Test

CONTROL LOGIC
NVM TRIM
CIRCUITSVSS

Figure 2. Simplified Accelerometer Functional Block Diagram

Table 1. Maximum Ratings(Maximum ratings are the limits to which the device can be exposed without causing permanent damage.)
RatingSymbol

Value

Unit

Maximum Acceleration (all axis)

gmax

±5000

g

Supply Voltage

VDD–0.3 to +3.6

V

Drop Test(1)

Ddrop

1.8

m

Storage Temperature Range

Tstg–40 to +125

°C

1. Dropped onto concrete surface from any axis.

ELECTRO STATIC DISCHARGE (ESD)WARNING: This device is sensitive to electrostatic
discharge.
Although the Freescale accelerometer contains internal
2000 V ESD protection circuitry, extra precaution must be
taken by the user to protect the chip from ESD. A charge ofover 2000 volts can accumulate on the human body or
associated test equipment. A charge of this magnitude canalter the performance or cause failure of the chip. When
handling the accelerometer, proper ESD precautions should
be followed to avoid exposing the device to discharges which
may be detrimental to its performance.

MMA7361LC
2

Sensors
Freescale Semiconductor

Table 2. Operating Characteristics
Unless otherwise noted: -40°C < TA < 85°C, 2.2 V < VDD < 3.6 V, Acceleration = 0g, Loaded output(1)Characteristic

Symbol

Min

Typ

Max

Unit

VDD
IDD
IDD
TA

2.2
—
—
-40

3.3
400
3
—

3.6
600
10
+85

V
μA
μA
°C

gFS
gFS

—
—

±1.5
±6.0

—
—

g
g

VOFF, TA

1.485
1.32
-2.0

1.65
1.65
±0.5

1.815
1.815
+2.0

V
v
mg/°C

S1.5g
S6g
S,TA

740
190.6
-0.0075800
206±0.002860
221.5+0.0075

mV/g
mV/g
%/°C

f-3dBXY
f-3dBZ
ZO
0gdetect

—
—
—
-0.4

400
300
32
0

—
—
—
+0.4

Hz
Hz
kΩ
g

Self Test
Output Response
XOUT, YOUTZOUT
Input Low
Input HighΔgSTXY
ΔgSTZ
VIL
VIH

+0.05
+0.8
VSS
0.7 VDD

-0.1
+1.0
—
—

—
+1.2
0.3 VDD
VDD

g
g
V
V

Noise
Power Spectral Density RMS (0.1 Hz – 1 kHz)(4)

nPSD

—

350

—

μg/ HztRESPONSE
tENABLE
tST

—
—
—

1.0
0.5
2.0

2.0
2.0
5.0

ms
ms
ms

fGCELLXY
fGCELLZ
fCLK

—
—
—

6.0
3.4
11

—
—
—

kHz
kHz
kHz

Output Stage Performance
Full-Scale Output Range (IOUT = 3 µA)

VFSO

VSS+0.1—

VDD–0.1

V

Nonlinearity, XOUT, YOUT, ZOUT

NLOUT

-1.0

—

+1.0

%FSO

VXY, XZ, YZ

-5.0

—

+5.0

%

(2)

Operating Range
Supply Voltage(3)Supply Current(4)Supply Current at Sleep Mode(4)Operating Temperature Range
Acceleration Range, X-Axis, Y-Axis, Z-Axis
g-Select: 0
g-Select: 1
Output Signal
Zero-g (TA = 25°C, VDD = 3.3 V)(5), (6)XYZ
Zero-g(4)Sensitivity (TA = 25°C, VDD = 3.3 V)
1.5g
6g
Sensitivity(4)Bandwidth Response
XY
Z
Output Impedance
0g-Detect

Control Timing
Power-Up Response Time(7)Enable Response Time(8)Self Test Response Time(9)Sensing Element Resonant Frequency
XY
ZInternal Sampling Frequency

Cross-Axis Sensitivity(10)VOFF

1. For a loaded output, the measurements are observed after an RC filter consisting of an internal 32 kΩ resistor and an external 3.3 nF capacitor(recommended as a minimum to filter clock noise) on the analog output for each axis and a 0.1μF capacitor on VDD - GND. The output sensor
bandwidth is determined by the Capacitor added on the output. f = 1/2π * (32 x 103) * C. C = 3.3 nF corresponds to BW = 1507 HZ, which is
the minimum to filter out internal clock noise.
2. These limits define the range of operation for which the part will meet specification.
3. Within the supply range of 2.2 and 3.6 V, the device operates as a fully calibrated linear accelerometer. Beyond these supply limits the device
may operate as a linear device but is not guaranteed to be in calibration.
4. This value is measured with g-Select in 1.5g mode.
5. The device can measure both + and – acceleration. With no input acceleration the output is at midsupply. For positive acceleration the output
will increase above VDD/2. For negative acceleration, the output will decrease below VDD/2.
6. For optimal 0g offset performance, adhere to AN3484 and AN3447
7. The response time between 10% of full scale VDD input voltage and 90% of the final operating output voltage.
8. The response time between 10% of full scale Sleep Mode input voltage and 90% of the final operating output voltage.
9. The response time between 10% of the full scale self test input voltage and 90% of the self test output voltage.
10. A measure of the device’s ability to reject an acceleration applied 90° from the true axis of sensitivity.

MMA7361LC
Sensors
Freescale Semiconductor

3

PRINCIPLE OF OPERATIONThe Freescale accelerometer is a surface-micromachined
integrated-circuit accelerometer.
The device consists of a surface micromachined
capacitive sensing cell (g-cell) and a signal conditioning ASIC
contained in a single package. The sensing element is sealed
hermetically at the wafer level using a bulk micromachined
cap wafer.
The g-cell is a mechanical structure formed fromsemiconductor materials (polysilicon) using semiconductor
processes (masking and etching). It can be modeled as a setof beams attached to a movable central mass that move
between fixed beams. The movable beams can be deflectedfrom their rest position by subjecting the system to an
acceleration (Figure 3).
As the beams attached to the central mass move, thedistance from them to the fixed beams on one side will
increase by the same amount that the distance to the fixed
beams on the other side decreases. The change in distanceis a measure of acceleration.
The g-cell beams form two back-to-back capacitors(Figure 3). As the center beam moves with acceleration, thedistance between the beams changes and each capacitor'svalue will change, (C = Aε/D). Where A is the area of thebeam, ε is the dielectric constant, and D is the distance
between the beams.
The ASIC uses switched capacitor techniques to measure
the g-cell capacitors and extract the acceleration data fromthe difference between the two capacitors. The ASIC also
signal conditions and filters (switched capacitor) the signal,
providing a high level output voltage that is ratiometric andproportional to acceleration.
Acceleration

Figure 3. Simplified Transducer Physical Model

SPECIAL FEATURES
0g-Detect
The sensor offers a 0g-Detect feature that provides a logic
high signal when all three axes are at 0g. This featureenables the application of Linear Freefall protection if thesignal is connected to an interrupt pin or a poled I/O pin on a
microcontroller.
Self Test
The sensor provides a self test feature that allows theverification of the mechanical and electrical integrity of theaccelerometer at any time before or after installation. Thisfeature is critical in applications such as hard disk drive

protection where system integrity must be ensured over thelife of the product. Customers can use self test to verify thesolderability to confirm that the part was mounted to the PCB
correctly. To use this feature to verify the 0g-Detect function,
the accelerometer should be held upside down so that theZ-axis experiences -1g. When the self test function is
initiated, an electrostatic force is applied to each axis tocause it to deflect. The X- and Y-axis are deflected slightly
while the Z-axis is trimmed to deflect 1g. This procedureassures that both the mechanical (g-cell) and electronic
sections of the accelerometer are functioning.
g-Select
The g-Select feature allows for the selection between two
sensitivities. Depending on the logic input placed on pin 10,
the device internal gain will be changed allowing it to function
with a 1.5g or 6g sensitivity (Table 3). This feature is ideal
when a product has applications requiring two different
sensitivities for optimum performance. The sensitivity can bechanged at anytime during the operation of the product. The
g-Select pin can be left unconnected for applications
requiring only a 1.5g sensitivity as the device has an internal
pull-down to keep it at that sensitivity (800 mV/g).
Table 3. g-Select Pin Description
g-Selectg-Range

Sensitivity

0

1.5g

800 mV/g

1

6g

206 mV/g

Sleep Mode
The 3 axis accelerometer provides a Sleep Mode that is
ideal for battery operated products. When Sleep Mode isactive, the device outputs are turned off, providing significant
reduction of operating current. A low input signal on pin 7(Sleep Mode) will place the device in this mode and reducethe current to 3 μA typ. For lower power consumption, it isrecommended to set g-Select to 1.5g mode. By placing a highinput signal on pin 7, the device will resume to normal modeof operation.
Filtering
The 3 axis accelerometer contains an onboard single-poleswitched capacitor filter. Because the filter is realized using
switched capacitor techniques, there is no requirement forexternal passive components (resistors and capacitors) to set
the cut-off frequency.
Ratiometricity
Ratiometricity simply means the output offset voltage andsensitivity will scale linearly with applied supply voltage. Thatis, as supply voltage is increased, the sensitivity and offset
increase linearly; as supply voltage decreases, offset andsensitivity decrease linearly. This is a key feature wheninterfacing to a microcontroller or an A/D converter because
it provides system level cancellation of supply induced errors
in the analog to digital conversion process.

MMA7361LC
4

Sensors
Freescale Semiconductor

BASIC CONNECTIONSPCB Layout

Pin Descriptions
Top View

POWER SUPPLY

P2
P3

Accelerometer

XOUT
YOUT

12

ZOUT

Pin Name

1

N/C

No internal connection
Leave unconnected

2

XOUT

X direction output voltage

3

YOUT

Y direction output voltage

4

ZOUT

Z direction output voltage

5

VSS

Power Supply Ground

6

VDD

Power Supply Input

7

Sleep

Logic input pin to enable product or Sleep Mode

8

NC

No internal connection
Leave unconnected

C

C

P1

C
C
C

A/DIN

C

Microcontroller

130g-Detect
Self Test

11

1
2
3

VSS

10

N/C

7

0g-Detect

Pin No.

A/DIN
A/DIN

Description

90g-DetectLinear Freefall digital logic output signal

10

g-Select

Logic input pin to select g level

11

N/C

Unused for factory trim
Leave unconnected

12

N/C

Unused for factory trim
Leave unconnected

13

Self Test

14

N/C

Input pin to initiate Self Test
Unused for factory trim
Leave unconnected

10

13

GND

0g-Delect

XOUT

6

VDD

YOUT

2

3.3 nF30.1 μF
5

7

Figure 6. Recommended PCB Layout for Interfacing
Accelerometer to Microcontroller
NOTES:
1. Use 0.1 µF capacitor on VDD to decouple the powersource.
2. Physical coupling distance of the accelerometer tothe microcontroller should be minimal.
3. Place a ground plane beneath the accelerometer toreduce noise, the ground plane should be attached toall of the open ended terminals shown in Figure 6.
4. Use a 3.3 nF capacitor on the outputs of theaccelerometer to minimize clock noise (from theswitched capacitor filter circuit).
5. PCB layout of power and ground should not couple
power supply noise.
6. Accelerometer and microcontroller should not be ahigh current path.
7. A/D sampling rate and any external power supply
switching frequency should be selected such thatthey do not interfere with the internal accelerometer
sampling frequency (11 kHz for the sampling
frequency). This will prevent aliasing errors.

9
g-Select

MMA7361LC

Logic
Input

P0

g-Select

Table 4. Pin Descriptions

VDD

Sleep
g-Select

N/C

Figure 4. Pinout Description

Logic
Input

VDD

VSS

Sleep

Logic
Input

VRH

N/C

9

VSS
VDD

VDD

Self Test

8

ZOUT

4

YOUT

5

XOUT

6

N/C

14

N/C

8. 10 MΩ or higher is recommended on XOUT, YOUT and
ZOUT to prevent loss due to the voltage divider
relationship between the internal 32 kΩ resistor andthe measurement input impedance.

3.3 nF
VSS
ZOUT
Sleep

4

3.3 nF

Figure 5. Accelerometer with Recommended
Connection Diagram
MMA7361LC
Sensors
Freescale Semiconductor

5

DYNAMIC ACCELERATION

Top View

+Y
4

3

2

1

7

+X

14

8

9

10

11

12

+Z

Bottom

-X

5

Top

6

Side View

-Z

13

-Y

: Arrow indicates direction of package movement.

14-Pin LGA Package

STATIC ACCELERATION
Direction of Earth's gravity field.*

Top View
6

5

4

3

2

1

7

14

X

13

Y

@ +1g = 2.45 V

5Z@ 0g = 1.65 V

OUT
OUT

12

1

@ 0g = 1.65 V

6

OUT

4

10

3

Z

9

2

8
7

OUT

OUT

13

@ +1g = 2.45 V

12

11

10

9

8

X

OUT

@ 0g = 1.65 V@ 0g = 1.65 V

OUT@ 0g = 1.65 V@ +1g = 2.45 V

Bottom1

Z

OUT@ 0g = 1.65 V

14

Y

OUT

OUT

Y

13

X

Bottom
X

12

11

2

13

11

3

12

10

4

11

9

5

10

8

6

9

7

14

8

Side View
Top

14

7

@ -1g = 0.85 V

Y@ 0g = 1.65 V

Z@ 0g = 1.65 V

OUT

OUT

Top
X

OUT

Y

@ 0g = 1.65 V

Z@ -1g =0.85 V

OUT

OUT

1

2

3

X

OUT

4

5

6

@ 0g = 1.65 VY@ -1g = 0.85 V

Z@ 0g = 1.65 V

OUT

OUT

@ 0g = 1.65 V* When positioned as shown, the Earth’s gravity will result in a positive 1g output.

MMA7361LC
6

Sensors
Freescale SemiconductorX-TCO mg/degC

LSL

-2

X-TCS %/degC

Target

-1

0

USL

1

2

Y-TCO mg/degC

LSL

-2

0

USL

1

2

Z-TCO mg/degC

LSL

-2

-0.005

0

USL

.005

.01

LSL

-0.01

Target-0.005

0

USL

.005

.01

Z-TCS %/degC

Target-1-0.01

TargetY-TCS %/degC

Target

-1

LSL

0

USL

1

2

LSL

-0.01

Target-0.005

0

USL

.005

.01

Figure 7. MMA7361LC Temperature Coefficient of Offset (TCO) and
Temperature Coefficient of Sensitivity (TCS) Distribution Charts

MMA7361LC
Sensors
Freescale Semiconductor

7

MINIMUM RECOMMENDED FOOTPRINT FOR SURFACE MOUNTED APPLICATIONSPCB Mounting Recommendations
MEMS based sensors are sensitive to Printed Circuit
Board (PCB) reflow processes. For optimal zero-g offset after
PCB mounting, care must be taken to PCB layout and reflow
conditions. Reference application note AN3484 for bestpractices to minimize the zero-g offset shift after PCB
mounting.
Surface mount board layout is a critical portion of the total
design. The footprint for the surface mount packages must be
the correct size to ensure proper solder connection interface
between the board and the package.
With the correct footprint, the packages will self-align whensubjected to a solder reflow process. It is always
recommended to design boards with a solder mask layer toavoid bridging and shorting between solder pads.

1

13

10x0.86x2

6
8
14x0.612x1

14x0.9

MMA7361LC
8

Sensors
Freescale SemiconductorPACKAGE DIMENSIONSCASE 1977-01
ISSUE A
14-LEAD LGA
MMA7361LC
Sensors
Freescale Semiconductor

9

PACKAGE DIMENSIONSCASE 1977-01
ISSUE A
14-LEAD LGA

MMA7361LC
10

Sensors
Freescale Semiconductor

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MMA7361LC
Rev. 003/2010