ADIS16334/PCBZ Analog Devices Inc, ADIS16334/PCBZ Datasheet - Page 9

• Manufacturer Part Number: ADIS16334/PCBZ
• Description: ADIS16334/PCB EVAL. BD. PB Free
• Manufacturer: Analog Devices Inc
• Series: iSensor™r

Specifications of ADIS16334/PCBZ

• Sensor Type: Gyroscope, 3 Axis
• Sensing Range: ±75 ~ 300°/s
• Interface: Serial
• Sensitivity: 0.0125°/sec/LSB
• Embedded: No
• Utilized Ic / Part: ADIS16334
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Supply: -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

THEORY OF OPERATION
The ADIS16334 is a six degree of freedom (6DOF) inertial sensing
system. This sensing system collects data autonomously and
makes it available to any processor system that supports a 4-wire
serial peripheral interface (SPI).
GYROSCOPES
Angular rate sensing in the ADIS16334 begins with a MEMS
gyroscope that operates on the principle of a resonator gyro. Two
polysilicon sensing structures each contain a dither frame that
is electrostatically driven to resonance, producing the necessary
velocity element to produce a Coriolis force during angular rate.
At two of the outer extremes of each frame, orthogonal to the
dither motion, are movable fingers that are placed between
fixed pickoff fingers to form a capacitive pickoff structure that
senses Coriolis motion. The resulting signal is fed to a series of
gain and demodulation stages that produce the electrical rate
signal output. The dual-sensor design rejects external g-forces
and vibration.
ACCELEROMETERS
Acceleration sensing in the ADIS16334 starts with a MEMS
accelerometer core on each axis, which provides a linear motion-to-
electrical transducer function. Tiny polysilicon springs to tether a
movable structure to a fixed frame inside the sensor core. The
springs and mass of the movable structure provide a dependable
relationship between acceleration and physical displacement
between them. The moving structure and fixed frame have
electrical plates in a balanced, differential capacitor network.
When experiencing dynamic or static acceleration, it causes a
physical deflection, which causes an imbalance in the capacitive
network. A modulation/de-modulation circuit translates the
capacitor imbalance into a representative electrical signal.
SENSOR
MEMS
Figure 9. Simplified Sensor Signal Processing Diagram
ADC
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CONTROLLER
DIGITAL I/O
FILTERING AND
CALIBRATION
DATA SAMPLING AND PROCESSING
The analog signals from each inertial sensor feed into a mixed
signal processing circuit, which includes buffering, analog
filtering, digital sampling, digital filtering, and calibration.
CALIBRATION
The digital processing stage includes a correction function for
each accelerometer and gyroscope sensor. Each sensor within
each unit has unique correction formulas, which optimize their
bias and sensitivity accuracy over temperature and supply. The full,
6DOF characterization also enables an internal frame alignment,
which minimizes cross-axis sensitivity and simplifies frame
alignment after system installation.
USER INTERFACE
SPI Interface
The user registers manage user access to both sensor data and
configuration inputs. Each 16-bit register has its own unique bit
assignment and two addresses: one for its upper byte and one for
its lower byte. Table 8 provides a memory map for each register,
along with its function and lower byte address. Each data collection
and configuration command both use the SPI, which consists of
four wires. The chip select ( CS ) signal activates the SPI interface
and the serial clock (SCLK) synchronizes the serial data lines.
Input commands clock into the DIN pin, one bit at a time, on
the SCLK rising edge. Output data clocks out of the DOUT pin
on the SCLK falling edge. As a SPI slave device, the DOUT contents
reflect the information requested using a DIN command.
REGISTERS
REGISTERS
CONTROL
OUTPUT
ADIS16334