ADIS16251ACCZ Analog Devices Inc, ADIS16251ACCZ Datasheet - Page 14

• Manufacturer Part Number: ADIS16251ACCZ
• Description: IC,Acceleration Detector,LGA,20PIN,PLASTIC
• Manufacturer: Analog Devices Inc
• Series: iSensor™r

Specifications of ADIS16251ACCZ

• Range °/s: ±20°/s, ±40°/s, ±80°/s
• Sensitivity: ±0.2%
• Typical Bandwidth: 49Hz
• Voltage - Supply: 4.75 V ~ 5.25 V
• Current - Supply: 18mA
• Output Type: SPI
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 20-LGA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: ADIS16251/PCBZ - BOARD EVALUATION FOR ADIS16251
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: Q3234523

ADIS16251
CALIBRATION
The ADIS16251 is factory-calibrated for sensitivity and bias. It
also provides several user calibration functions for simplifying
field-level corrections. The calibration factors are stored in
nonvolatile memory and are applied using the following linear
calibration equation:
where:
y is the calibrated output data.
m is the sensitivity scale factor.
x is the precalibration data.
b is the offset scale factor.
There are three options for system-level calibrations of the
bias in the ADIS16251: autonull, factory calibration restore,
and manual calibration updates. The autonull and factory reset
options are described in the Global Commands section. Optional
field-level calibrations use the preceding equation and require
the following two steps:
1.
2.
The GYRO_OFF provides a calibration range of ±75°/sec,
and its contents are nonvolatile. The GYRO_SCALE register
provides a calibration range of 0 to 1.9995, and its contents are
also nonvolatile.
Table 8. GYRO_OFF Register Definition
Address
0x15, 0x14
1
Table 9. GYRO_OFF Bit Descriptions
Bit
15:14
13:0
Table 10. GYRO_SCALE Register Definition
Address
0x17, 0x16
1
2
Table 11. GYRO_SCALE Bit Descriptions
Bit
15:12
11:0
Scale is the weight of each LSB.
Scale is the weight of each LSB.
Equates to a scale factor of one.
y = mx + b
Characterize the behavior of the ADIS16251 at predefined
critical operating conditions.
Use this characterization data to calculate and load the
contents of GYRO_OFF (b) and GYRO_SCALE (m).
Description
Not used
Data bits
Description
Not used
Data bits
Scale
0.00458°/sec
Scale
0.0487%
1
1
Default
0x0000
Default
0x0800
2
Format
Twos
complement
Format
Binary
Access
R/W
Access
R/W
Rev. A | Page 14 of 14
GLOBAL COMMANDS
The ADIS16251 provides global commands for common opera-
tions such as autonull, factory calibration restore, manual flash
update, auxiliary DAC latch, and software reset. Each of these
global commands has a unique control bit assigned to it in the
COMMAND register and is initiated by writing a 1 to its
assigned bit.
The autonull function does two things: it resets the contents of
the ANGL_OUT register to zero, and it adjusts the GYRO_OUT
register to zero. This automated adjustment requires the follow-
ing two steps:
1.
2.
For optimal calibration accuracy, set the number of filtering taps
to its maximum, wait for the appropriate number of samples
to process through the filter, and then exercise this option.
The factory calibration restore command sets the contents of
GYRO_OFF to 0x0000 and GYRO_SCALE to 0x0800, erasing
any field-level calibration contents. The manual flash update
writes the contents of each nonvolatile register into flash mem-
ory for storage. This process takes approximately 50 ms and
requires the power supply voltage to be within specification for
the duration of the event. It is worth noting that this operation
also automatically follows the autonull and factory reset
commands.
The DAC latch command loads the contents of AUX_DAC into
the DAC latches. Since the AUX_DAC contents must be updated
one byte at a time, this command ensures a stable DAC output
voltage during updates. Finally, the software reset command
sends the ADIS16251 digital processor into a restart sequence,
effectively doing the same thing as the RST line.
Table 12. COMMAND Register Definition
Address
0x3F, 0x3E
Table 13. COMMAND Bit Descriptions
Bit
15:8
7
6:4
3
2
1
0
Read GYRO_OUT.
Write the opposite of this value into the GYRO_OFF
register. Sensor noise influences the accuracy of this step.
Description
Not used
Software reset command
Not used
Manual flash update command
Auxiliary DAC data latch
Factory calibration restore command
Autonull command
Default
N/A
Format
N/A
Access
Write only