Document Number: MMA7260QT
Rev 3, 06/2007

Freescale Semiconductor
Technical Data

±1.5g - 6g Three Axis Low-g
Micromachined Accelerometer
The MMA7260QT low cost capacitive micromachined accelerometerfeatures signal conditioning, a 1-pole low pass filter, temperaturecompensation and g-Select which allows for the selection among 4
sensitivities. Zero-g offset full scale span and filter cut-off are factory set andrequire no external devices. Includes a Sleep Mode that makes it ideal for
handheld battery powered electronics.
Features

MMA7260QT: XYZ AXISACCELEROMETER±1.5g/2g/4g/6g

Selectable Sensitivity (1.5g/2g/4g/6g)
Low Current Consumption: 500 μA
Sleep Mode: 3 μA
Low Voltage Operation: 2.2 V – 3.6 V
6mm x 6mm x 1.45mm QFNHigh Sensitivity (800 mV/g @ 1.5g)
Fast Turn On Time
Integral Signal Conditioning with Low Pass Filter
Robust Design, High Shocks Survivability
Pb-Free Terminations
Environmentally Preferred Package
Low Cost

Bottom View

16 LEADQFNCASE 1622-02

Typical Applications
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
Gaming: Tilt and Motion Sensing, Event Recorder
Robotics: Motion Sensing

16 15

MMA7260QT–40 to +105°C

1622-02

QFN-16, Tray

MMA7260QR2–40 to +105°C

1622-02

QFN-16,Tape & Reel

ZOUT

g-Select2 2

11 N/C

VDD 3

10 N/C

VSS 4

9 N/C
5

6

7

8
N/C

Package

Device Name

12

N/C

Package
Drawing

Sleep
Mode

g-Select1 1

N/C

Temperature
Range

14 13

N/C

ORDERING INFORMATIONYOUTTop View

N/C

•
•
•
•
•
•
•
•

XOUT

•
•
•
•
•
•
•
•
•
•
•
•

MMA7260QT

Figure 1. Pin Connections© Freescale Semiconductor, Inc., 2005-2007. All rights reserved.

VDD

g-Select1
g-Select2

G-CellSensorSleep Mode

Oscillator

Clock
Generator

X-TempComp

XOUT

C to V
Converter

Gain+
FilterY-TempComp

YOUT

Z-TempComp

ZOUTControl Logic
EEPROM Trim Circuits

VSS

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

±2000

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.

MMA7260QT
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Table 2. Operating Characteristics
Unless otherwise noted: –40°C < TA < 105°C, 2.2 V < VDD < 3.6 V, Acceleration = 0g, Loaded output(1)Characteristic

SymbolMin

Supply Voltage(3)

VDD

2.2

3.3

3.6

V

Supply Current

IDD

—

500

800

μA

Supply Current at Sleep Mode(4)

IDD

—

3.0

10

μA

Operating Temperature Range

TA

–40

—

+105

°C

g-Select1 & 2: 00

gFS

—

±1.5

—

g

g-Select1 & 2: 10

gFS

—

±2.0

—

g

g-Select1 & 2: 01

gFS

—

±4.0

—

g

g-Select1 & 2: 11

gFS

—

±6.0

—

g

VOFF

1.485

1.65

1.815

Operating Range

Typ

Max

Unit

(2)

Acceleration Range, X-Axis, Y-Axis, Z-Axis

Output Signal
Zero-g (TA = 25°C, VDD = 3.3 V)(5)
Zero-g(4)X-axisY-axisZ-axisSensitivity (TA = 25°C, VDD = 3.3 V)
1.5g
2g
4g
6g
Sensitivity(4)VOFF, TAV
mg/°C

±2.6(6)±0.6±3.8(7)(6)±5.8±5.9(7)

(6)

±1.0

±0.8

±0.8(7)

S1.5g

740

800

860

mV/g

S2g

555

600

645

mV/g

S4g

277.5

300

322.5

mV/g

S6g

185

200

215

mV/g

±0.02(6)±0.02±0.02(7)±0.01(6)±0.01±0.01(7)

(6)

±0.00

±0.01(7)

±5.8

S,TA

X-axisY-axisZ-axisBandwidth Response

%/°C

±0.01

XY

f-3dB

—

350

—

Hz

Z

f-3dB

—

150

—

Hz

RMS (0.1 Hz – 1 kHz)(4)

nRMS

—

4.7

—

mVrms

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

nPSD

—

350

—

μg/ HzPower-Up Response Time(8)tRESPONSE

—

1.0

2.0

ms

Enable Response Time(9)tENABLE

—

0.5

2.0

ms

XY

fGCELL

—

6.0

—

kHz

Z

fGCELL

—

3.4

—

kHz

fCLK

—

11

—

kHz

Noise

Control Timing

Sensing Element Resonant Frequency

Internal Sampling Frequency
Output Stage Performance
Full-Scale Output Range (IOUT = 30 µA)
Nonlinearity, XOUT, YOUT, ZOUT
Cross-Axis Sensitivity(10)VFSO

VSS+0.25—

VDD–0.25

V

NLOUT

–1.0

—

+1.0

%FSO

VXY, XZ, YZ

—

—

5.0

%

1. For a loaded output, the measurements are observed after an RC filter consisting of a 1.0 kΩ resistor and a 0.1 µF capacitor on VDD-GND.
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. These values represent the 10th percentile, not the minimum.
7. These values represent the 90th percentile, not the maximum.
8. The response time between 10% of full scale VDD input voltage and 90% of the final operating output voltage.
9. The response time between 10% of full scale Sleep Mode input voltage and 90% of the final operating output voltage.
10. A measure of the device’s ability to reject an acceleration applied 90 from the true axis of sensitivity.

MMA7260QT
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3

PRINCIPLE OF OPERATIONThe Freescale accelerometer is a surface-micromachined
integrated-circuit accelerometer.
The device consists of two surface micromachined
capacitive sensing cells (g-cell) and a signal conditioning
ASIC contained in a single integrated circuit package. The
sensing elements are 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

SPECIAL FEATURES
g-Select
The g-Select feature allows for the selection among 4
sensitivities present in the device. Depending on the logic
input placed on pins 1 and 2, the device internal gain will bechanged allowing it to function with a 1.5g, 2g, 4g, or 6g
sensitivity (Table 3). This feature is ideal when a product hasapplications requiring different sensitivities for optimum
performance. The sensitivity can be changed at anytime
during the operation of the product. The g-Select1 andg-Select2 pins 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 (800mV/g).
Table 3. g-Select Pin Descriptions
g-Select2

g-Select1

g-Range

Sensitivity

0

0

1.5g

800 mV/g

012g

600 mV/g

104g

300 mV/g11

6g

200 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 12(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-Select1 and g-Select2 to 1.5g mode.
By placing a high input signal on pin 12, the device will
resume to normal mode of operation.
Filtering
The 3 axis accelerometer contains onboard single-poleswitched capacitor filters. 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.

Figure 3. Simplified Transducer Physical Model

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.

MMA7260QT
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BASIC CONNECTIONSPCB Layout

Pin Descriptions

g-Select1

ZOUT

POWER SUPPLY

14 13

1

12

VDD

Sleep Mode

C

C

VRH

VDD

P0

VSS

3

10

N/C

g-Select1

P1

VSS

4

9

N/C

g-Select2

P2

5

6

7

8

Accelerometer

VDD

N/C

N/C

N/C

11

N/C

2

N/C

g-Select2

VSS
Sleep Mode

XOUT

R

YOUT

R

ZOUT

R

C
C

Figure 4. Pinout Description
Table 4. Pin Descriptions
Pin No.

Pin Name1g-Select1

Logic input pin to select g level.

2

g-Select2

Logic input pin to select g level.

3

VDD

Power Supply Input

4

VSSPower Supply Ground

5-7

N/C

No internal connection.
Leave unconnected.

8 - 11

N/C

Unused for factory trim.
Leave unconnected.

12Sleep Mode

13

ZOUT

Z direction output voltage.

14

YOUT

Y direction output voltage.

15

XOUT

X direction output voltage.

16

N/C

No internal connection.
Leave unconnected.

Logic
Inputs1

Logic input pin to enable product or
Sleep Mode.

g-Select1

ZOUT

13

1 kΩ
0.1 μF

MMA7260QT
3

VDD

YOUT

14

0.1 μF
4
12
Logic
Input

A/DIN
A/DIN

Description

2 g-Select2

VDD

C

A/DIN

C

Microcontroller

16 15

YOUT

N/C

XOUT

Top View

VSS
Sleep ModeXOUT 15

Figure 6. Recommended PCB Layout for Interfacing
Accelerometer to Microcontroller
NOTES:
1. To ensure start up operation below 0°C, verify VDD
line has the ability to reach 2.2 V in < 0.1 ms as
measured on the device at the VDD pin. Rise times
greater than this most likely will prevent cold start up
operation.
2. Physical coupling distance of the accelerometer tothe microcontroller should be minimal.
3. The flag underneath the package is internallyconnected to ground. It is not recommended for theflag to be soldered down.
4. 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.
5. Use an RC filter with 1.0 kΩ and 0.1 µF on the
outputs of the accelerometer to minimize clock noise(from the switched capacitor filter circuit).
6. PCB layout of power and ground should not couple
power supply noise.

1 kΩ

7. Accelerometer and microcontroller should not be ahigh current path.

0.1 μF

8. 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.

1 kΩ
0.1 μF

Figure 5. Accelerometer with Recommended
Connection Diagram

9. PCB layout should not run traces or vias under the
QFN part. This could lead to ground shorting to theaccelerometer flag.

MMA7260QT
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5

DYNAMIC ACCELERATION
Top View

+Y
14

13

1

12

2

11

3

10

4

9
5

6

7

-X

-Z

Bottom

+X

15

Top

16

Side View

+Z

8

-Y

: Arrow indicates direction of mass movement.
16-Pin QFN Package

STATIC ACCELERATION
Direction of Earth’s gravity field.*

Top View

Side View

XOUT@ 0g = 1.65 V
YOUT @ -1g = 0.85 V
ZOUT@ 0g = 1.65 V

XOUT @ 0g = 1.65 V
YOUT @ 0g = 1.65 V
ZOUT@ +1g = 2.45 V

XOUT @ -1g = 0.85 V
YOUT @ 0g = 1.65 V
ZOUT@ 0g = 1.65 V

XOUT @ +1g = 2.45 V
YOUT @ 0g = 1.65 V
ZOUT@ 0g = 1.65 V

XOUT @ 0g = 1.65 V
YOUT @ 0g = 1.65 V
ZOUT@ -1g = 0.85 V

XOUT @ 0g = 1.65 V
YOUT @ +1g = 2.45 V
ZOUT@ 0g = 1.65 V* When positioned as shown, the Earth’s gravity will result in a positive 1g output.

MMA7260QT
6

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Freescale SemiconductorMINIMUM RECOMMENDED FOOTPRINT FOR SURFACE MOUNTED APPLICATIONS
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.
The flag underneath the package is internally connected to
ground. It is not recommended for the flag to be soldered
down.

Pin 1 ID
(non-metallic)

Do not solder down
flag and 4 corner
ground pads on the
package for
consumer application
Do not place any top
metal patterns or via
structures beneaththe package

Note: The die pad (flag) is not generally recommended to besoldered down for consumer product application. All dimensions
are in mm.

Figure 7. PCB Footprint for 16-Lead QFN, 6x6 mm forConsumer Grade Products and Applications

MMA7260QT
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Freescale Semiconductor

7

PCB DESIGN GUIDELINES
The following are the recommended guidelines to follow
for mounting QFN sensors for either automotive or consumer
applications.
1. NSMD (Non Solder Mask Defined) is shown in
Figure 8.
2. Solder mask opening = PCB land pad +0.1 mm.
3. Stencil aperture size = PCB land pad – 0.025mm, as
shown in Figure 9 with a 6mil stencil.
4. Do not place insertion components or vias at a
distance less than 2mm from the package land area.
5. Signal trace connected to pads should be as
symmetric as possible. Put dummy traces if there is
NC pads, in order to have same length of exposed
trace for all pads. Signal traces with 0.1mm width andmin. 0.5mm length for all PCB land pad near package
are recommended as shown in Figure 8 and
Figure 9. Wider trace can be continued after the
0.5mm zone.
6. Use a standard pick and place process andequipment (no hand soldering process).
7. It is recommended to use a cleanable solder pastewith an additional cleaning step after SMT mount
8. It is recommended to avoid screwing down the PCB
to fix it into an enclosure since this may cause the
PCB to bend.
9. PC boards should be rated for multiple reflow of leadfree conditions with 260°C maximum temperature.

PCB land pattern - NSMD

Package Pad

Signal trace 0.1mm widthand 0.5mm (min) length nearpackage. Wider trace can becontinued after these traces.

0.50 mm0.55 mm
Cu: 0.55 x 0.50 mm sq.

Solder mask opening =PCB land pad +0.1mm=0.65x0.60 mm sq.
Figure 8. NSMD Solder Mask Design Guidelines
Signal trace near package: 0.1mm width and
0.5mm (min) length are recommended nearpackage. Wider trace can be continued after
these.

Stencil opening (black) for land pad (yellow)= PCB landing pad -0.025mm= 0.525mmx0,475mm

Package foot pirnt

Figure 9. Stencil Design Guidelines

MMA7260QT
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Freescale SemiconductorPACKAGE DIMENSIONSPAGE 1 OF 3

CASE 1622-02
ISSUE B
16-LEAD QFNMMA7260QT
Sensors
Freescale Semiconductor

9

PACKAGE DIMENSIONSPAGE 2 OF 3

CASE 1622-02
ISSUE B
16-LEAD QFNMMA7260QT
10

Sensors
Freescale SemiconductorPACKAGE DIMENSIONSPAGE 3 OF 3

CASE 1622-02
ISSUE B
16-LEAD QFNMMA7260QT
Sensors
Freescale Semiconductor

11

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MMA7260QT
Rev. 306/2007