EVAL-ADXL350Z Analog Devices, EVAL-ADXL350Z Datasheet - Page 14

• Manufacturer Part Number: EVAL-ADXL350Z
• Description: Acceleration Sensor Development Tools EB
• Manufacturer: Analog Devices

Specifications of EVAL-ADXL350Z

• Rohs: yes
• Interface Type: I2C, SPI
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Product: Evaluation Boards
• Factory Pack Quantity: 1

ADXL350
THEORY OF OPERATION
The
system with a selectable measurement range of ±1 g, ±2 g, ±4 g,
or ±8 g. It measures both dynamic acceleration resulting from
motion or shock and static acceleration, such as gravity, which
allows the device to be used as a tilt sensor.
The sensor is a polysilicon surface-micromachined structure
built on top of a silicon wafer. Polysilicon springs suspend the
structure over the surface of the wafer and provide a resistance
against acceleration forces.
Deflection of the structure is measured using differential capacitors
that consist of independent fixed plates and plates attached to the
moving mass. Acceleration deflects the beam and unbalances the
differential capacitor, resulting in a sensor output whose amplitude
is proportional to acceleration. Phase-sensitive demodulation is
used to determine the magnitude and polarity of the acceleration.
Table 6. Power Sequencing
Condition
Power Off
Bus Disabled
Bus Enabled
Standby or Measurement
ADXL350
is a complete 3-axis acceleration measurement
V
Off
On
Off
On
S
V
Off
Off
On
On
DD I/O
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Description
The device is completely off, but there is the potential for a communication
bus conflict.
The device is on in standby mode, but communication is unavailable and
creates a conflict on the communication bus. The duration of this state should
be minimized during power-up to prevent a conflict.
No functions are available, but the device does not create a conflict on the
communication bus.
At power-up, the device is in standby mode, awaiting a command to enter
measurement mode, and all sensor functions are off. After the device is
instructed to enter measurement mode, all sensor functions are available.
POWER SEQUENCING
Power can be applied to V
damaging the ADXL350. All possible power-on modes are
summarized in Table 6.
The interface voltage level is set with the interface supply volt-
age, V
does not create a conflict on the communication bus. For
single-supply operation, V
supply, V
differ from V
long as V
After V
consumption is minimized and the device waits for V
applied and for the command to enter measurement mode to be
received. (This command can be initiated by setting the measure
bit in the POWER_CTL register (Address 0x2D).) In addition, any
register can be written to or read from to configure the part while
the device is in standby mode. It is recommended to configure the
device in standby mode and then to enable measurement mode.
Clearing the measure bit returns the device to the standby mode.
DD I/O
S
is applied, the device enters standby mode, where power
S
S
. In a dual-supply application, however, V
is greater than V
, which must be present to ensure that the
S
to accommodate the desired interface voltage, as
DD I/O
S
DD I/O
or V
.
can be the same as the main
DD I/O
in any sequence without
Data Sheet
DD I/O
ADXL350
DD I/O
can
to be