Preliminary Datasheet
SMB365
Three-axis accelerometer
Bosch Sensortec
Triaxial
±2g/±10g
Accelerometer SMB365
K
EY
F
EATURES
-
-
-
-
-
-
-
-
-
-
Three-axis accelerometer
Switchable g-range (2g/10g)
Standard SMD package: QFN 4.0x4.0 mm
2
footprint, 1.2mm height
4mg resolution at 50Hz bandwidth
Ultra-low power ASIC: 600µA at V
DD
2.5V
SPI interface
Interrupt feature for mobile wake-up or zero-g detection (free fall)
Full self-test capability
RoHS lead-free compliant
Based on automotive-proven Bosch Silicon Surface Micromachining Process
T
YPICAL
A
PPLICATIONS
Tilt, motion and vibration sensing in
-
Cell phones
-
Handhelds
-
Computer peripherals
-
Man-machine interfaces
-
Virtual reality
-
Games
G
ENERAL
D
ESCRIPTION
The SMB365 is a triaxial low-g acceleration sensor for consumer market applications. It allows
measurements of static as well as dynamic accelerations. Due to its three perpendicular axes it
gives the absolute orientation in a gravity field. As all other Bosch inertial sensors, it is a two-
chip arrangement. An application-specific IC evaluates the output of a three-channel microme-
chanical acceleration-sensing element that works according to the differential capacitance prin-
ciple. The underlying micromachining process has proven its capability in more than 100 million
Bosch accelerometers and gyroscopes so far.
The SMB365 provides a digital 10bit output signal via an SPI interface. With an appropriate SPI
command the full measurement range can be chosen to 2g or 10g. A first-order filter with a
pole-frequency of 50Hz is included to provide preconditioning of the measured acceleration
signal. Typical noise level and quantization lead to a sensitivity resolution of 4mg or an accuracy
of 0.3° in an inclination sensing application, respectively. The current consumption is typically
600µA at a supply voltage of 2.5V. Furthermore, the sensor can be switched into a low-power
mode where it informs the host system about an acceleration change via an interrupt pin. This
feature can be used to wake-up the host system from a sleep mode.
The sensor also features full self-test capability. It is activated via SPI command which results in
a physical deflection of the seismic mass in the sensing element due to an electrostatic force.
Thus, it provides full testing of the complete signal evaluation path including the micromachined
sensor structure and the evaluation ASIC.
The sensor is available in a standard SMD QFN package with a footprint of 4x4mm
2
and a
height of 1.2mm.
Rev. 1.2
Page 1
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as
copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
7211RB11
.
Preliminary Datasheet
SMB365
Three-axis accelerometer
Bosch Sensortec
T
ABLE OF
C
ONTENTS
1
2
3
SPECIFICATION................................................................................................................................... 3
ABSOLUTE MAXIMUM RATINGS....................................................................................................... 4
SPI INTERFACE ................................................................................................................................... 5
3.1
3.2
3.3
SPI S
PECIFICATION
.......................................................................................................................... 5
SPI P
ROTOCOL
................................................................................................................................ 6
SPI T
IMING
...................................................................................................................................... 7
4
MEMORY .............................................................................................................................................. 8
4.1
EEPROM........................................................................................................................................ 8
4.1.1
Register Arithmetic ................................................................................................................. 8
4.2
G
LOBAL
M
EMORY
M
APPING
.............................................................................................................. 9
5
OPERATION ....................................................................................................................................... 10
5.1
5.2
5.3
5.4
5.5
5.6
5.7
5.8
5.9
G
ENERAL
D
ESCRIPTION
.................................................................................................................. 10
O
PERATION
M
ODES AND
S
ENSITIVITY
R
ESOLUTION
.......................................................................... 10
I
NTERRUPT
F
EATURE
(L
OW
P
OWER
M
ODE
) ..................................................................................... 11
A
CCELERATION
D
ATA
F
ORMAT
........................................................................................................ 13
S
ELF
T
EST
..................................................................................................................................... 13
P
OLARITY OF THE
A
CCELERATION
O
UTPUT
...................................................................................... 14
P
IN
C
ONFIGURATION
...................................................................................................................... 15
C
ONNECTING
D
IAGRAM
................................................................................................................... 16
H
ANDLING
I
NSTRUCTION
................................................................................................................ 17
6
PACKAGE .......................................................................................................................................... 17
6.1
6.2
6.3
6.4
O
UTLINE
D
IMENSIONS
..................................................................................................................... 17
M
ARKING
....................................................................................................................................... 19
M
OISTURE
S
ENSITIVITY
L
EVEL AND
S
OLDERING
............................................................................... 19
R
O
HS C
OMPLIANCY
....................................................................................................................... 19
E
NGINEERING
S
AMPLES
.................................................................................................................. 20
L
IMITING VALUES
............................................................................................................................ 20
L
IFE SUPPORT
-
AND AUTOMOTIVE APPLICATIONS
.............................................................................. 20
7
DISCLAIMER ...................................................................................................................................... 20
7.1
7.2
7.3
Rev. 1.2
Page 2
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as
copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
7211RB11
.
Preliminary Datasheet
SMB365
Three-axis accelerometer
Bosch Sensortec
1
Specification
Symbol
g
FS2g
g
FS10g
V
DDA
V
DDD
I
DD
I
DDlpm
I
DDsbm
T
A
only for SPI I/O;
V
DDD
≤
V
DDA
digital and analog
digital and analog
digital and analog
-40
Condition
switchable via
SPI command
2.3
1.6
Min
Typ
2
10
2.5
1.8
600
500
5
+85
3.6
3.6
Max
Units
g
g
V
V
µA
µA
µA
°C
Parameter
O
PERATING
R
ANGE
Acceleration Range
Supply Voltage
Analog
Supply Voltage
Digital
Supply Current in
Normal Mode
Supply Current in
Low-Power Mode
Supply Current in
Standby Mode
Operating
Temperature
O
UTPUT
S
IGNAL
Sensitivity
Zero-g Offset
2
Zero-g Offset
Temperature Drift
Ratiometricity Error
3
Bandwidth
Nonlinearity
S
2g
S
10g
Off
TCO
δ
rat_off
f
-3dB
NL
g-range 2g
g-range 10g
T
A
=25°C, V
DDD
=2.5V
-15°C
≤
T
A
≤
+55°C
Offset drift vs. V
DDA
1
st
order filter
best fit straight line
2g xy
2g z
10g xy
10g z
240
47
256
51
±10
±0.5
±30
272
55
LSB/g
LSB/g
LSB
LSB/K
LSB/V
25
50
±0.5
300
150
60
30
1
75
Hz
%FS
Self Test Response
TST
activated
via SPI
LSB
Output Noise
n
rms
rms
LSB
Rev. 1.2
Page 3
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as
copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
7211RB11
.
Preliminary Datasheet
SMB365
Three-axis accelerometer
Bosch Sensortec
M
ECHANICAL
C
HARACTERISTICS
Cross Axis
Sensitivity
Alignment Error
S
relative contribution
between 3 axes
relative to package
outline
0.2
±0.5
%
°
δ
a
2
Absolute Maximum Ratings
Parameter
Supply Voltage
Storage Temperature
range
duration
≤
50µs
Mechanical Shock
duration
≤
1.0ms
free fall onto
hard surfaces
ESD
HBM, at any pin
CDM
Condition
V
DDD
and V
DDA
Min
-0.3
-50
Max
3.6
+150
10,000
2,000
1.5
2
500
Units
V
°C
g
g
m
kV
V
Rev. 1.2
Page 4
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as
copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
7211RB11
.
Preliminary Datasheet
SMB365
Three-axis accelerometer
Bosch Sensortec
3
-
-
-
-
-
-
-
-
-
SPI Interface
16-bit SPI protocol (mode 3)
Clock frequency up to 8MHz
1 read/write bit (R/W=0 for writing, R/W=1 for reading)
7 address bits
8 data bits
The most significant bit (MSB) is transferred first during address and data phases.
The data acquisition by the sensor occurs at the rising edge of SCK.
The output data provided by the sensor is synchronized with the falling edges of SCK.
The CSB input has a 120kΩ pull-up resistor to V
DDD
.
The SPI is used for regular reading of the acceleration signal coded on 10 bits. Periodically, an update of
the digitalized temperature is also available (see the timing diagrams for a detailed description). For a
complete readout of the acceleration, two successive read cycles are required because a maximum of 8
bits is readable within a cycle. A 10-bit coded signal is split into 7 MSB and 3 LSB.
The SPI interface is also used for the EEPROM programming/reading. Due to finite access time, the read
cycle of an EEPROM byte needs two SPI cycles, in order to keep the standard protocol.
3.1
SPI Specification
Symbol
f
SPI
C
SPI
V
IL_SPI
V
IH_SPI
V
HYST_SPI
R
CSB
0.7*V
DDD
0.1* V
DDD
70
120
190
Condition
V
DDD
minimum
Min
0.5
Typ
Max
8
25
0.3* V
DDD
Units
MHz
pF
V
V
V
kΩ
Parameter
Clock input frequency
Capacitive load (MISO)
Input-low level
Input-high level
Hysteresis of the inputs
CSB pull-up resistor
Rev. 1.2
Page 5
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as
copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
7211RB11
.
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