ETC SMB365

Preliminary Datasheet
SMB365
Bosch Sensortec
Three-axis accelerometer
Triaxial ±2g/±10g Accelerometer SMB365
KEY FEATURES
-
Three-axis accelerometer
Switchable g-range (2g/10g)
Standard SMD package: QFN 4.0x4.0 mm2 footprint, 1.2mm height
4mg resolution at 50Hz bandwidth
Ultra-low power ASIC: 600µA at VDD 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
TYPICAL APPLICATIONS
Tilt, motion and vibration sensing in
- Cell phones
- Handhelds
- Computer peripherals
- Man-machine interfaces
- Virtual reality
- Games
GENERAL DESCRIPTION
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 twochip arrangement. An application-specific IC evaluates the output of a three-channel micromechanical acceleration-sensing element that works according to the differential capacitance principle. 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 4x4mm2 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
Bosch Sensortec
Three-axis accelerometer
TABLE OF CONTENTS
1
SPECIFICATION................................................................................................................................... 3
2
ABSOLUTE MAXIMUM RATINGS....................................................................................................... 4
3
SPI INTERFACE ................................................................................................................................... 5
3.1
3.2
3.3
4
SPI SPECIFICATION .......................................................................................................................... 5
SPI PROTOCOL ................................................................................................................................ 6
SPI TIMING ...................................................................................................................................... 7
MEMORY .............................................................................................................................................. 8
4.1
EEPROM........................................................................................................................................ 8
4.1.1
Register Arithmetic ................................................................................................................. 8
4.2
GLOBAL MEMORY MAPPING .............................................................................................................. 9
5
OPERATION ....................................................................................................................................... 10
5.1
5.2
5.3
5.4
5.5
5.6
5.7
5.8
5.9
6
PACKAGE .......................................................................................................................................... 17
6.1
6.2
6.3
6.4
7
GENERAL DESCRIPTION .................................................................................................................. 10
OPERATION MODES AND SENSITIVITY RESOLUTION .......................................................................... 10
INTERRUPT FEATURE (LOW POWER MODE) ..................................................................................... 11
ACCELERATION DATA FORMAT ........................................................................................................ 13
SELF TEST ..................................................................................................................................... 13
POLARITY OF THE ACCELERATION OUTPUT ...................................................................................... 14
PIN CONFIGURATION ...................................................................................................................... 15
CONNECTING DIAGRAM................................................................................................................... 16
HANDLING INSTRUCTION ................................................................................................................ 17
OUTLINE DIMENSIONS..................................................................................................................... 17
MARKING ....................................................................................................................................... 19
MOISTURE SENSITIVITY LEVEL AND SOLDERING ............................................................................... 19
ROHS COMPLIANCY ....................................................................................................................... 19
DISCLAIMER ...................................................................................................................................... 20
7.1
7.2
7.3
ENGINEERING SAMPLES .................................................................................................................. 20
LIMITING VALUES ............................................................................................................................ 20
LIFE SUPPORT- AND AUTOMOTIVE APPLICATIONS .............................................................................. 20
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
Bosch Sensortec
Three-axis accelerometer
1
Specification
Parameter
OPERATING RANGE
Acceleration Range
Supply Voltage
Analog
Supply Voltage
Digital
Symbol
gFS2g
gFS10g
Condition
switchable via
SPI command
VDDA
VDDD
only for SPI I/O;
VDDD ≤ VDDA
Supply Current in
Normal Mode
IDD
digital and analog
Supply Current in
Low-Power Mode
IDDlpm
digital and analog
Supply Current in
Standby Mode
IDDsbm
digital and analog
Operating
Temperature
Min
TA
Typ
Max
Units
2
g
10
g
2.3
2.5
3.6
V
1.6
1.8
3.6
V
600
µA
500
µA
5
µA
-40
+85
°C
OUTPUT SIGNAL
S2g
g-range 2g
240
256
272
LSB/g
S10g
g-range 10g
47
51
55
LSB/g
Off
TA=25°C, VDDD=2.5V
±10
LSB
Zero-g Offset
Temperature Drift
TCO
-15°C ≤ TA ≤ +55°C
±0.5
LSB/K
Ratiometricity Error3
δrat_off
Offset drift vs. VDDA
±30
LSB/V
Sensitivity
Zero-g Offset
2
st
Bandwidth
f-3dB
1 order filter
Nonlinearity
NL
best fit straight line
Self Test Response
Output Noise
Rev. 1.2
TST
nrms
activated
via SPI
25
50
±0.5
2g xy
300
2g z
150
10g xy
60
10g z
30
rms
1
75
Hz
%FS
LSB
LSB
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
Bosch Sensortec
Three-axis accelerometer
MECHANICAL
CHARACTERISTICS
2
Cross Axis
Sensitivity
S
relative contribution
between 3 axes
0.2
%
Alignment Error
δa
relative to package
outline
±0.5
°
Absolute Maximum Ratings
Parameter
Supply Voltage
Condition
VDDD and VDDA
Min
-0.3
Max
3.6
Units
V
-50
+150
°C
duration ≤ 50µs
10,000
g
duration ≤ 1.0ms
2,000
g
1.5
m
2
kV
500
V
Storage Temperature
range
Mechanical Shock
free fall onto
hard surfaces
ESD
HBM, at any pin
CDM
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
Bosch Sensortec
Three-axis accelerometer
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 VDDD.
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
Parameter
Clock input frequency
Capacitive load (MISO)
Symbol
fSPI
Condition
CSPI
VDDD minimum
Min
0.5
Typ
Max
8
Units
MHz
25
pF
0.3* VDDD
V
Input-low level
VIL_SPI
Input-high level
VIH_SPI
0.7*VDDD
V
VHYST_SPI
0.1* VDDD
V
RCSB
70
Hysteresis of the inputs
CSB pull-up resistor
Rev. 1.2
120
190
kΩ
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.
Preliminary Datasheet
SMB365
Bosch Sensortec
Three-axis accelerometer
3.2
SPI Protocol
The used protocol corresponds to the standard SPI mode 3.
SPI Memory Write cycle description
CSB
SCK
MOSI
R/W
A6
A5
A4
A3
A2
A1
A0
D7
D6
D5
D4
D3
D2
D1
D0
HiZ
MISO
A6 .. A0 :
D7 .. D0 :
7 Address bits
8 Data bits
SCK frequency : 8 MHz max.
SPI Memory Read cycle description (divided in two SPI cycles due to EEPROM read access time)
CSB
SCK
MOSI
R/W
A6
A5
A4
A3
A2
A1
A0
HiZ
MISO
A6 .. A0 :
D7 .. D0 :
R/W
X
X
X
X
X
D6
D5
D4
X
X
X
X
D3
D2
D1
D0
A6
A5
A4
HiZ
A3
A2
A1
A0
X
D7
D6
D5
D4
D3
D2
D1
D0
HiZ
7 Address bits
8 Data bits
SPI Acceleration/Temperature Read cycle description
CSB
SCK
MOSI
R/W
A6
A5
A4
HiZ
MISO
A6 .. A0 :
D7 .. D0 :
A3
A2
A1
A0
X
D7
HiZ
7 Address bits
8 Data bits
EM/WIL 08/10/03
Due to the standard 16-bit protocol, the digital codes for the acceleration values must be read by two
successive SPI cycles. The user has to read the 7 MSB first and then the 3 LSB. It is also possible to
read only the 7 MSB.
The 3 LSB are protected in such a way that during the read-out of the 7 MSB the LSB are not changed or
updated. The update of the LSB does not take place before the MSB are read again. Therefore it cannot
happen that a mixed acceleration value is read.
Rev. 1.2
Page 6
© 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
Bosch Sensortec
Three-axis accelerometer
3.3
SPI Timing
1
2
CSB
3
4
SCK
7
MISO
MOSI
6
5
Rev. 1.2
#
1
Parameter
CSB setup time
Symbol
tsetup_csb
Min
16
2
CSB hold time
thold_csb
16
3
SCK high period
thigh_sck
25
4
SCK low period
tlow_sck
25
5
MOSI setup time
tsetup_mosi
10
6
MOSI hold time
thold_mosi
10
7
MISO delay time
tvalid_miso
22
Units
ns
Page 7
© 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
Bosch Sensortec
Three-axis accelerometer
4
Memory
4.1
EEPROM
An EEPROM is used to store the non-volatile data, calibration parameters and the current working
modes. These are in detail
g-range (2g or 10g)
operation mode (full performance, low-power, standby)
interrupt mode (global or independent)
interrupt acceleration threshold and hysteresis level
self test.
4.1.1
Register Arithmetic
The following arithmetics are used for memory registers.
Register
AX|Y|Z (acceleration values)
Rev. 1.2
Format
2's complement
Bit width
10
THRESHOLD
(TH or TH_X|Y|Z)
unsigned positive
either 5 or 7
HYSTERESIS
(HY or HY_X|Y|Z)
unsigned positive
either 3 or 7
Page 8
© 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
Bosch Sensortec
Three-axis accelerometer
4.2
Global Memory Mapping
The global memory mapping comprises EEPROM and latches.
bit7
bit6
bit5
bit4
bit3
bit2
bit1
bit0
40h - 7Fh
30h - 3Fh
2Ch - 2Fh
2Bh
2Ah
29h
hy_Y(2)
hy_Z(2)
hy_X(2)
hy_Y(1)
hy(6)
hy_Z(1)
th(6)
hy_X(1)
hy_Y(0)
hy(5)
hy_Z(0)
th(5)
hy_X(0)
th_Y(4)
hy(4)
th_Z(4)
th(4)
th_X(4)
th_Y(3)
hy(3)
th_Z(3)
th(3)
th_X(3)
Oscillator trimming
28h
th_Y(2)
hy(2)
th_Z(2)
th(2)
th_X(2)
th_Y(1)
hy(1)
th_Z(1)
th(1)
th_X(1)
Bandgap trimming
27h
Self Test
Sensor ID
26h
Int. mode
Operation mode + PROT
25h
2g / 10g
24h
23h
22h
21h
20h
unused bits
1Fh
1Eh
A_Y (LSB)
A_Y (Current value of Z axis Acceleration) (MSB)
1Dh
unused bits
A_Z (LSB)
A_Z (Current value of Y axis Acceleration) (MSB)
1Ch
1Bh
unused bits
1Ah
A_X (LSB)
A_X (Current value of X axis Acceleration) (MSB)
unused addresses
10h-19h
0FH
0Eh
0Dh
0Ch
0Bh
reserved adress
0Ah
09h
08h
07h
06h
05h
04h
03h
02h
01h
00h
EEPROM
Protected
EEPROM
Read-only
th_Y(0)
hy(0)
th_Z(0)
th(0)
th_X(0)
Reset
NA
NA
00h
00h
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
00h
00h
00h
00h
00h
00h
NA
00h
00h
00h
NA
00h
00h
NA
00h
00h
00h
00h
00h
00h
00h
00h
00h
Image
The image registers are read-only. All EEPROM registers are duplicated into the corresponding image
registers.
Rev. 1.2
Page 9
© 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
Bosch Sensortec
Three-axis accelerometer
5
Operation
5.1
General Description
The SMB365 is a triaxial low-g acceleration sensor. It allows measurements of static as well as dynamic
accelerations in all three dimensions. Due to its three perpendicular axes it gives the absolute orientation
in a gravity field. The sensor is set up as a two-chip arrangement in a standard mold package. An
application-specific IC evaluates the output of a three-channel micromechanical acceleration-sensing
element that works according to the differential capacitance principle.
The ASIC is produced in a standard CMOS process. The production of the sensing element is based on
standard semiconductor process steps followed by special steps providing the functional structure. These
steps start with the deposition of a thick epitaxial layer on a sacrificial oxide. The large thickness allows
the design of working capacitances of up to 1pF. This in turn enables the hybrid two-chip assembly. The
poly layer is patterned by deep reactive ion etching in an inductive coupled plasma (DRIE-ICP, the socalled Bosch process). A large aspect ratio and a very high anisotropy is achieved by periodic passivation
of the side walls in between the etch intervals. Afterwards the sacrificial layer is removed. Eventually the
sensing element is hermetically sealed by a bulk mircromachined cap to prevent damages of the
structure by dicing, packaging and operation of the device. The encapsulation is performed in a
cleanroom environment to reduce the risk of particle contamination to a minimum. Finally, the sensor is
packaged in a standard surface mountable micro leadframe QFN housing. Here the ASIC is stacked onto
the sensing element.
In the ASIC, three different so called self-balancing bridges convert the change of capacitances into
voltages. These signals are preconditioned by first order 50Hz filters and then multiplexed, amplified and
ASIC
Sensing Element
C1x
C2x
Self-Balancing
Bridge X-axis
Low-Pass
Filter (30Hz)
SCK
Amplifier
(50Hz)
CSB
C1y
C2y
Self-Balancing
Bridge Y-Axis
Low-Pass
Filter (30Hz)
ADC
MUX
SPI
MOSI
(50Hz)
INT
C1z
C2z
Self-Balancing
Bridge Z-Axis
Low-Pass
Filter (30Hz)
EEPROM
PTAT
(50Hz)
VDDD
VDDA
VSS
converted into a digital output signal.
5.2
MISO
Operation Modes and Sensitivity Resolution
The sensor can be operated in three different modes:
•
normal mode
•
low-power mode
•
standby mode.
The different modes are chosen via the SPI interface (see EEPROM mapping). In normal mode the
sensor reaches its full performance. In the low-power (interrupt) mode the sensor is fully functional but
Rev. 1.2
Page 10
© 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
Bosch Sensortec
Three-axis accelerometer
the performance is reduced. If the sensor is switched to standby, the ASIC enters a sleep mode. Only a
part of the logic and the SPI block are active. All analog blocks including EEPROM are deactivated.
The sensitivity resolution varies as follows:
Operation Mode
Normal
Sensitivity Resolution
10
Units
Low-power (Interrupt)
7
bit
Standby
-
10bit roughly corresponds to 4mg, 7bit to 30mg resolution.
Due to non-perfect decoupling, any SPI activity will perturb the A/D conversions. The best case is the
absence of SPI activity during A/D conversion which is not possible all the time because of
synchronization issues.
The A/D conversion for the acceleration signals about X-, Y-, Z-axis are performed sequentially.
Therefore it is very unlikely that the A/D conversion of a given axis will be systematically perturbed by SPI
activity because the duration of a SPI cycle is very short compared to an A/D conversion. Of course, this
is only valid if there are not to many other peripherals on this SPI bus.
5.3
Interrupt Feature (Low Power Mode)
The sensor (slave) can inform the host system (master) about an acceleration change even if SPI
communication is not taking place. This feature can be used as a “wake-up” for instance. It is working in
both g-range modes (2g and 10g), but only in low-power mode. No interrupt is generated in normal mode
and/or during SPI traffic.
In case of a certain acceleration change the sensor will send an interrupt signal (INT, active high) via the
interrupt pin and will keep it up as long as the acceleration is larger then a certain hysteresis level.
Via SPI command it can be chosen between a global and a channel independent interrupt mode. In the
global mode the same values for interrupt threshold and hysteresis level are valid for all three channels
(both with 7 bit resolution, i.e. 16mg resolution in 2g-mode). In the independent mode theses values can
be chosen individually for each channel (interrupt 5 bit, hysteresis 3 bit resolution, i.e. 63mg/250mg
resolution in 2g-mode).
The interrupt is activated when the acceleration signal (absolute value) in at least one of the channels
exceeds its individual interrupt threshold (TH_X, TH_Y and TH_Z respectively) or the global interrupt
threshold (TH) depending on the chosen interrupt mode. It is deactivated as soon as all channels fall (or
still are) below their respective levels threshold levels minus their respective hysteresis values (individual:
HY_X, HY_Y. HY_Z; global: HY).
As mentioned in the register arithmetic, all threshold and hysteresis values (TH_X, TH_Y, TH_Z, TH,
HY_X, HY_Y. HY_Z and HY) are unsigned. The acceleration codes for the 3 channels A_X, A_Y and A_Z
have a 2’s complement format and a coding on 10 bits. The MSB of the acceleration code gives the sign
of the acceleration and the 9 LSB contain the information of the absolute acceleration value.
● Example of an interrupt generated by the X channel for the interrupt mode 1 (individual):
INT is activated when ABS(A_X) ≥ 16*TH_X
Rev. 1.2
Page 11
© 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
Bosch Sensortec
Three-axis accelerometer
INT is deactivated when ABS(A_X) < 16*TH_X - 64*HY_X
and no interrupt activation by the other channels
● Example of an interrupt generated by the X channel for the interrupt mode 0 (global):
INT is activated when ABS(A_X) ≥ 4*TH
INT is deactivated when ABS(A_X) < 4*TH - 4*HY
and no interrupt activation by the other channels
Notice that TH_X(4..2) is always larger than HY_X, i.e. TH_X>4*HY_X. This is also valid for all other
channels and the global values, where we have TH>HY (both are coded on 7 bits). If the user does not
respect this rule (for all channels) or as soon as one of the interrupt thresholds is set to 0, the interrupt is
deactivated. The EEPROM registers dedicated to interrupt thresholds and hysteresis levels accept all
code combinations which is required for storing the chip alignment error/cross axis sensitivity data.
If the user modifies any threshold and/or hysteresis value, the interrupt output is not updated immediately
but only after a refresh of the acceleration codes.
Application Hints
Wake-Up:
A normal lifting of the sensor (like taking an object from a table) easily leads to acceleration gradients of
25g/s=100mg/4ms and to an amplitude of 500mg.
Zero-g/Free Fall Detection:
The interrupt can also be used for zero-g or free-fall detection. To this end 2g- and global interrupt mode
have to be chosen and the output signal has to be interpreted as active low.
In case of a free fall all axes will experience zero-g. Therefore the interrupt threshold should be chosen
close to 0 with the minimum hysteresis. The exact values depend on the application but a minimum value
of ~100mg is required taking into account the 0g-offset tolerance and temperature drift:
In this case the interrupt will be at high level if the sensor is in normal use. Only in case of a free fall all 3
axes will experience accelerations smaller than 100mg and the output will switch to low level.
Rev. 1.2
Page 12
© 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
Bosch Sensortec
Three-axis accelerometer
5.4
Acceleration Data Format
The description of the digital signal is "2's complement". From negative to positive accelerations, the
following sequence for the ±2g measurement range can be observed (±10g correspondingly):
-2.000g :
-1.996g :
...
-0.004g :
0.000g :
+0.004g :
...
+1.992g :
+1.996g :
5.5
10 0000 0000
10 0000 0001
11 1111 1111
00 0000 0000
00 0000 0001
01 1111 1110
01 1111 1111
Self Test
The sensor features an on-chip self-test which can be activated by changing the corresponding self test
bit in the corresponding via SPI. The self test is realized by a physical deflection of the seismic mass 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 self test is activated by setting the self test activation bit to 1. The test works in all measurement
modes (2g, 10g, normal, low-power) and acts on all three channels simultaneously. The typical change in
output will be 300LSB in the 2g-mode and 60LSB in the 10g-mode. The self test response remains as a
static offset on the output as long as the self test register is not set back to 0.
While the self test is activated, any acceleration or gravitational force applied to the sensor will be
observed in the output signal as a superposition of both acceleration and self test signal.
Output Signal [LSB]
Self Test Response
Self Test Activation Bit
1
0
Rev. 1.2
Page 13
© 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
Bosch Sensortec
Three-axis accelerometer
5.6
Polarity of the Acceleration Output
If the sensor is accelerated in the indicated directions, the corresponding channel will deliver a positive
acceleration signal (dynamic acceleration). If the sensor is at rest and the force of gravity is working along
the indicated directions, the output of the corresponding channel will be negative.
z
x
top side
y
1
Rev. 1.2
Page 14
© 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
Bosch Sensortec
Three-axis accelerometer
5.7
Pin Configuration
Pin 1 identifier
Pin No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Rev. 1.2
Name
NC
VDDA
VSS
DNC
CSB
DNC
INT
SCK
DNC
MOSI
MISO
VDDD
NC
NC
Function
not connected
ASIC analog core supply
ASIC ground
do not connect
SPI select (chip select bar)
do not connect
Interrupt output signal
SPI clock
do not connect
SPI output (master out slave in)
SPI input (master in slave out)
ASIC digital core supply
not connected
not connected
Page 15
© 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
Bosch Sensortec
Three-axis accelerometer
5.8
Connecting Diagram
The following external components are recommended to decouple the power source.
1.8V
INT
VDDD
CSB
SCK
MISO
2.5V
VDDA
VSS
C1
100nF
C2
100nF
C3
10nF
MOSI
5.9
Handling Instruction
Micromechanical sensors are designed to sense acceleration with high accuracy even at low amplitudes
and contain highly sensitive structures inside the sensor element. The micromachined sensors can
tolerate mechanical shocks up to several thousand g's. However, these limits might be exceeded in
conditions with extreme shock loads such as e.g. hammer blow on or next to the sensor, dropping of the
sensor onto hard surfaces etc.
We recommend to avoid g-forces beyond the specified limits (see section 2) during transport, handling
and mounting of the sensors in a defined and qualified installation process.
Rev. 1.2
Page 16
© 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
Bosch Sensortec
Three-axis accelerometer
6
Package
6.1
Outline Dimensions
The sensor housing is a standard QFN package. It is compliant with JEDEC Standard MO-220. Its
dimensions are the following:
Rev. 1.2
Page 17
© 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
Bosch Sensortec
Three-axis accelerometer
Rev. 1.2
Page 18
© 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
Bosch Sensortec
Three-axis accelerometer
6.2
Marking
product part number
date code
sensor lot number
ASIC lot number
41003
YYWW
XXXXX
ZZZZZZ
pin 1 identifier
Engineering Samples are marked with the following symbol: *
6.3
Moisture Sensitivity Level and Soldering
The moisture sensitivity level of the SMB365 sensors corresponds to JEDEC Level 3, see also
-
IPC/JEDEC J-STD-020C "Joint Industry Standard: Moisture/Reflow Sensitivity Classification for
Nonhermetic Solid State Surface Mount Devices"
-
IPC/JEDEC J-STD-033A "Joint Industry Standard: Handling, Packing, Shipping and Use of
Moisture/Reflow Sensitive Surface Mount Devices".
The sensor fulfils the lead-free soldering requirements of the above-mentioned IPC/JEDEC standard, i.e.
reflow soldering with a peak temperature up to 260°C.
6.4
RoHS Compliancy
The SMB365 sensor meets the requirements of the EC restriction of hazardous substances (RoHS)
directive, see also
"Directive 2002/95/EC of the European Parliament and of the Council of 27 January 2003 on the
restriction of the use of certain hazardous substances in electrical and electronic equipment".
Rev. 1.2
Page 19
© 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
Bosch Sensortec
Three-axis accelerometer
7
Disclaimer
7.1
Engineering Samples
Engineering samples (marked with *) may not fulfill the complete technical data within this specification.
As well, Engineering samples (marked with *) are not determined for use in safety relevant automotive
applications, life support appliances reselling or passing to final consumers. The customer indemnifies
Bosch Sensortec for product liability claims or waives of recourse to Bosch Sensortec, if third parties
advance due to or in connection with a failure, a defect in function or misuse of the customer samples
supplied by Bosch Sensortec.
7.2
Limiting values
Limiting values given are in accordance with the Absolute Maximum Ratings (Chapter 2). Stress above
one or more of the limiting values may cause permanent damage to the device. Operation of the device
at these or at any other conditions above is not implied. Exposure to limiting values for extended periods
may also affect device reliability.
7.3
Life support- and automotive applications
The SMB365 is not designed for use in life support- or safety relevant automotive appliances, devices, or
systems where malfunction of these products can reasonably be expected to result in personal injury. Again,
the customer of Bosch Sensortec using or selling the SMB365 for use in such applications do so at one’s own
risk and agree again to fully indemnify Bosch Sensortec for any damages resulting from such improper use or
sale.
Rev. 1.2
Page 20
© 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
Bosch Sensortec
Three-axis accelerometer
Document History and Modification
Rev. No Chapter
0.0
6.1
1.1
5.7
1.11
1.2
7
5.7
1
4.2
5.7
Description of Modification/Changes
Name
- New outline dimensions
- New pin configuration
Review
- Disclaimer
- Pin1 identifier
Test signal z
Memory Mapping
Pin allocation
Date
02-Feb-06
27-Apr-06
27-May-06
30-May-06
Bosch Sensortec GmbH
Gerhard-Kindler-Strasse 8
72770 Reutlingen
[email protected]
www.bosch-sensortec.com
Modifications reserved | Printed in Germany
Version_1.2_062006
Rev. 1.2
Page 21
© 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.