Compact, Precision
Six Degrees of Freedom Inertial Sensor
Data Sheet
ADIS16445
Rev. F Document Feedback
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FEATURES
Triaxial digital gyroscope with digital range scaling
±62°/sec, ±125°/sec, ±250°/sec settings
Axis-to-axis alignment, <0.05°
Triaxial digital accelerometer, ±5 g minimum
Autonomous operation and data collection
No external configuration commands required
175 ms start-up time
Factory calibrated sensitivity, bias, and axial alignment
Calibration temperature range: −40°C to +85°C
SPI-compatible serial interface
Embedded temperature sensor
Programmable operation and control
Automatic and manual bias correction controls
Bartlett window FIR length, number of taps
Digital I/O: data ready, alarm indicator, general-purpose
Alarms for condition monitoring
Enable external sample clock input up to 1.1 kHz
Single command self-test
Single-supply operation: 3.15 V to 3.45 V
2000 g shock survivability
Operating temperature range: −40°C to +105°C
APPLICATIONS
Platform stabilization and control
Navigation
Robotics
GENERAL DESCRIPTION
The ADIS16445 iSensor® device is a complete inertial system
that includes a triaxial gyroscope and a triaxial accelerometer.
Each sensor in the ADIS16445 combines industry-leading
iMEMS® technology with signal conditioning that optimizes
dynamic performance. The factory calibration characterizes
each sensor for sensitivity, bias, and alignment. As a result, each
sensor has its own dynamic compensation formulas that provide
accurate sensor measurements.
The ADIS16445 provides a simple, cost-effective method for
integrating accurate, multiaxis inertial sensing into industrial
systems, especially when compared with the complexity and
investment associated with discrete designs. All necessary motion
testing and calibration are part of the production process at the
factory, greatly reducing system integration time. Tight orthogonal
alignment simplifies inertial frame alignment in navigation systems.
The SPI and register structures provide a simple interface for
data collection and configuration control.
The ADIS16445 has a compatible pinout for systems that cur-
rently use other Analog Devices, Inc., IMU products, such as
the ADIS16334 or the ADIS16485. The ADIS16445 is packaged
in a module that is approximately 24.1 mm × 37.7 mm × 10.8 mm
and has a standard connector interface.
FUNCTIONAL BLOCK DIAGRAM
CONTROLLER
CLOCK
TRIAXIAL
GYRO
TRIAXIAL
ACCEL
POWER
MANAGEMENT
CS
SCLK
DIN
DOUT
GND
VDD
TEMP
VDD
DIO1 DIO2 DIO3 DIO4 RST
SPI
SELF T EST I/O ALARMS
OUTPUT
DATA
REGISTERS
USER
CONTROL
REGISTERS
CALIBRATION
AND
FILTERS
ADIS16445
11051-001
Figure 1.
ADIS16445 Data Sheet
Rev. F | Page 2 of 22
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications ....................................................................................... 1
General Description ......................................................................... 1
Functional Block Diagram .............................................................. 1
Revision History ............................................................................... 2
Specifications ..................................................................................... 3
Timing Specifications .................................................................. 5
Absolute Maximum Ratings ............................................................ 6
ESD Caution .................................................................................. 6
Pin Configuration and Function Descriptions ............................. 7
Typical Performance Characteristics ............................................. 8
User Registers .................................................................................... 9
User Interface .................................................................................. 10
Reading Sensor Data .................................................................. 10
Device Configuration ................................................................ 11
Output Data Registers .................................................................... 12
Gyroscopes .................................................................................. 12
Accelerometers ............................................................................ 12
Internal Temperature ................................................................. 13
System Functions ............................................................................ 14
Global Commands ..................................................................... 14
Product Identification ................................................................ 14
Self-Test Function ....................................................................... 14
Status/Error Flags ....................................................................... 15
Memory Management ............................................................... 15
Input/Output Configuration ......................................................... 16
Data Ready Indicator ................................................................. 16
General-Purpose Input/Output................................................ 16
Digital Processing Configuration ................................................. 17
Gyroscopes/Accelerometers ..................................................... 17
Input Clock Configuration ....................................................... 17
Calibration ....................................................................................... 18
Gyroscopes .................................................................................. 18
Accelerometers ........................................................................... 18
Flash Updates .............................................................................. 19
Restoring Factory Calibration .................................................. 19
Alarms .............................................................................................. 20
Static Alarm Use ......................................................................... 20
Dynamic Alarm Use .................................................................. 20
Alarm Reporting ........................................................................ 20
Applications Information .............................................................. 21
Mounting Tips ............................................................................ 21
Power Supply Considerations ................................................... 21
ADIS16445/PCBZ ...................................................................... 21
PC-Based Evaluation Tools ....................................................... 21
Outline Dimensions ....................................................................... 22
Ordering Guide .......................................................................... 22
REVISION HISTORY
12/15—Rev. E to Rev. F
Change to Features Section ............................................................. 1
6/15—Rev. D to Rev. E
Changed ADIS16445AMLZ to ADIS16445BMLZ ......... Throughout
Changes to Features Section and General Description Section ........ 1
Changes to Table 1 .................................................................................. 3
Changes to Table 3 .................................................................................. 6
Changes to Figure 9 .............................................................................. 10
Changes to ADIS16445/PCBZ Section and Figure 22 ................... 21
Changes to Ordering Guide ................................................................ 22
10/14—Rev. C to Rev. D
Changes to Gyroscopes, Bias Temperature Coefficient
Parameter, and Accelerometers, Bias Temperature Coefficient
Parameter, Table 1 ............................................................................. 3
Changes to Table 41 ........................................................................ 20
5/14—Rev. B to Rev. C
Change to General Description Section ......................................... 1
Change to Status/Error Flags Section .......................................... 15
Added Mounting Tips Section...................................................... 21
7/13—Rev. A to Rev. B
Change to Linear Acceleration Effect on Bias Parameter, Table 1 .... 3
Changes to Burst Read Function Section .................................... 11
3/13—Rev. 0 to Rev. A
Changes to Table 1 ............................................................................. 3
Deleted Mounting Approaches Section ....................................... 21
Updated Outline Dimensions ....................................................... 22
10/12—Revision 0: Initial Version
Data Sheet ADIS16445
Rev. F | Page 3 of 22
SPECIFICATIONS
TA = 25°C, VDD = 3.3 V, angular rate = 0°/sec, dynamic range = ±250°/sec ± 1 g, unless otherwise noted.
Table 1.
Parameter Test Conditions/Comments Min Typ Max Unit
GYROSCOPES
Dynamic Range ±250 °/sec
Initial Sensitivity ±250°/sec, see Table 12 0.01 °/sec/LSB
±125°/sec 0.005 °/sec/LSB
±62°/sec 0.0025 °/sec/LSB
Repeatability1 −40°C ≤ TA ≤ +85°C 1 %
Sensitivity Temperature Coefficient
−40°C ≤ T
A
≤ +85°C
±40
ppm/°C
Misalignment Axis to axis ±0.05 Degrees
Axis to frame (package) ±0.5 Degrees
Nonlinearity Best fit straight line ±0.1 % of FS
Bias Repeatability1, 2 −40°C ≤ TA ≤ +85°C, 1 σ 0.5 °/sec
In-Run Bias Stability 1 σ, SMPL_PRD = 0x0001 12 °/hr
Angular Random Walk 1 σ, SMPL_PRD = 0x0001 0.56 °/√hr
Bias Temperature Coefficient −40°C ≤ TA ≤ +85°C ±0.005 °/sec/°C
Linear Acceleration Effect on Bias Any axis, 1 σ ±0.015 °/sec/g
Bias Supply Sensitivity +3.15 V ≤ VDD ≤ +3.45 V ±0.2 °/sec/V
Output Noise ±250°/sec range, no filtering 0.22 °/sec rms
Rate Noise Density
f = 25 Hz, ±250°/sec range, no filtering
0.011
°/sec/√Hz rms
−3 dB Bandwidth 330 Hz
Sensor Resonant Frequency 17.5 kHz
ACCELEROMETERS
Each axis
Dynamic Range ±5 g
Initial Sensitivity See Table 16 for data format 0.2475 0.25 0.2525 mg/LSB
Repeatability1 −40°C ≤ TA ≤ +85°C 1 %
Sensitivity Temperature Coefficient −40°C ≤ TA ≤ +85°C ±40 ppm/°C
Misalignment Axis to axis ±0.2 Degrees
Axis to frame (package) ±0.5 Degrees
Nonlinearity Best fit straight line ±0.2 % of FS
Bias Repeatability1, 2 −40°C ≤ TA ≤ +85°C, 1 σ ±8 mg
In-Run Bias Stability 1 σ, SMPL_PRD = 0x0001 0.075 mg
Velocity Random Walk 1 σ, SMPL_PRD = 0x0001 0.073 m/sec/√hr
Bias Temperature Coefficient
−40°C ≤ T
A
≤ +85°C
±0.04
m
g
/°C
Bias Supply Sensitivity +3.15 V ≤ VDD ≤ +3.45 V 1.5 mg/V
Output Noise No filtering 2.25 mg rms
Noise Density No filtering 0.105 mg/√Hz rms
−3 dB Bandwidth 330 Hz
Sensor Resonant Frequency 5.5 kHz
TEMPERATURE
Sensitivity See Table 17 0.07386 °C/LSB
LOGIC INPUTS3
Input High Voltage, VIH 2.0 V
Input Low Voltage, VIL 0.8 V
Logic 1 Input Current, IIH VIH = 3.3 V ±0.2 ±10 µA
Logic 0 Input Current, IIL VIL = 0 V
All Pins Except RST 40 60 µA
RST Pin 1 mA
Input Capacitance, CIN 10 pF
ADIS16445 Data Sheet
Rev. F | Page 4 of 22
Parameter Test Conditions/Comments Min Typ Max Unit
DIGITAL OUTPUTS3
Output High Voltage, VOH ISOURCE = 1.6 mA 2.4 V
Output Low Voltage, VOL ISINK = 1.6 mA 0.4 V
FLASH MEMORY Endurance4 10,000 Cycles
Data Retention5 TJ = 85°C 20 Years
FUNCTIONAL TIMES6 Time until new data is available
Power-On Start-Up Time 175 ms
Reset Recovery Time7 55 ms
Flash Memory Back-Up Time 55 ms
Flash Memory Test Time 20 ms
Automatic Self-Test Time
SMPL_PRD = 0x0001
16
ms
CONVERSION RATE
xGYRO_OUT, xACCL_OUT SMPL_PRD = 0x0001 819.2 SPS
Clock Accuracy ±3 %
Sync Input Clock8 0.8 1.1 kHz
POWER SUPPLY Operating voltage range, VDD 3.15 3.3 3.45 V
Power Supply Current VDD = 3.15 V 74 mA
1 The repeatability specifications represent analytical projections, which are based off of the following drift contributions and conditions: temperature hysteresis (−40°C
to +85°C), electronics drift (high-temperature operating life test: 85°C, 500 hours), drift from temperature cycling (JESD22, Method A104-C, Method N, 500 cycles,
−40°C to +85°C), rate random walk (10 year projection), and broadband noise.
2 Bias repeatability describes a long-term behavior, over a variety of conditions. Short-term repeatability is related to the in-run bias stability and noise density specifications.
3 The digital I/O signals are driven by an internal 3.3 V supply, and the inputs are 5 V tolerant.
4 Endurance is qualified as per JEDEC Standard 22, Method A117, and measured at −40°C, +25°C, +85°C, and +125°C.
5 The data retention lifetime equivalent is at a junction temperature (TJ) of 85°C as per JEDEC Standard 22, Method A117. Data retention lifetime decreases with junction
temperature.
6 These times do not include thermal settling and internal filter response times (330 Hz bandwidth), which may affect overall accuracy.
7 The RST line must be held low for at least 10 μs to assure a proper reset and recovery sequence.
8 The sync input clock functions below the specified minimum value but at reduced performance levels.
Data Sheet ADIS16445
Rev. F | Page 5 of 22
TIMING SPECIFICATIONS
TA = 25°C, VDD = +3.3 V, unless otherwise noted.
Table 2.
Parameter Description
Normal Mode Burst Read
Unit Min1 Typ Max Min1 Typ Max
fSCLK Serial clock 0.01 2.0 0.01 1.0 MHz
tSTALL Stall period between data 9 N/A2 µs
tREADRATE Read rate 40 µs
tCS Chip select to SCLK edge 48.8 48.8 ns
tDAV DOUT valid after SCLK edge 100 100 ns
tDSU DIN setup time before SCLK rising edge 24.4 24.4 ns
tDHD DIN hold time after SCLK rising edge 48.8 48.8 ns
tSCLKR, tSCLKF SCLK rise/fall times, not shown in timing diagrams 5 12.5 5 12.5 ns
tDR, tDF DOUT rise/fall times, not shown in timing diagrams 5 12.5 5 12.5 ns
t
SFS
CS
high after SCLK edge
5
5
ns
t1 Input sync positive pulse width 25 25 µs
tSTDR Input sync to data ready valid transition 670 670 µs
tNV Data invalid time 210 210 µs
t3 Input sync period 910 910 µs
1 Guaranteed by design and characterization, but not tested in production.
2 When using the burst read mode, the stall period is not applicable.
Timing Diagrams
CS
SCLK
DOUT
DIN
1 2 3 4 5 6 15 16
R/W A5A6 A4 A3 A2 D2
MSB DB14
D1 LSB
DB13 DB12 DB10DB11 DB2 LSBDB1
tCS tSFS
tDAV
tDHD
tDSU
11051-002
Figure 2. SPI Timing and Sequence
CS
SCLK
tREADRATE
tSTALL
11051-003
Figure 3. Stall Time and Data Rate
CLOCK
DATA
READY
t
1
t
3
t
NV
t
STDR
11051-004
Figure 4. Input Clock Timing Diagram
ADIS16445 Data Sheet
Rev. F | Page 6 of 22
ABSOLUTE MAXIMUM RATINGS
Table 3.
Parameter Rating
Acceleration
Any Axis, Unpowered
2000
g
Any Axis, Powered 2000 g
VDD to GND −0.3 V to +3.45 V
Digital Input Voltage to GND −0.3 V to +VDD + 0.3 V
Digital Output Voltage to GND −0.3 V to +VDD + 0.3 V
Temperature
Operating Range −40°C to +105°C
Storage Range −65°C to +125°C1, 2
1 Extended exposure to temperatures outside the specified temperature
range of −40°C to +105°C can adversely affect the accuracy of the factory
calibration. For best accuracy, store the parts within the specified operating
range of −40°C to +105°C.
2 Although the device is capable of withstanding short-term exposure to
150°C, long-term exposure threatens internal mechanical integrity.
Stresses at or above those listed under Absolute Maximum Rat-
ings may cause permanent damage to the product. This is a
stress rating only; functional operation of the product at these
or any other conditions above those indicated in the operational
section of this specification is not implied. Operation beyond
the maximum operating conditions for extended periods may
affect product reliability.
Table 4. Package Characteristics
Package Type
θJA
(°C/W)
θJC
(°C/W)
Mass
(grams)
20-Lead Module (ML-20-3) 36.5 16.9 15
ESD CAUTION
Data Sheet ADIS16445
Rev. F | Page 7 of 22
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
19
DIO4/CLKIN
DOUT
CS
RST
VDD DIO2
GND
DNC
DNC
DNC
DIO3
SCLK
DIN
DIO1
VDD VDD
GND
GND
DNC
DNC
20
17
18
15
16
13
14
11
12
9
10
7
8
5
6
3
4
1
2
ADIS16445
TOP VIEW
(No t t o Scal e)
NOTES
1. THIS REPRESENTATION DISPLAYS THE TOP VI EW W HEN THE
CONNECTO R IS V ISI BLE AND FACING UP.
2. M ATING CO NNE CTOR: S AM TEC CLM- 110- 02 OR EQ UIVALENT .
3. DNC = DO NO T CO NNE CT.
11051-005
Figure 5. Pin Configuration
PI N 1
PI N 20
11051-006
Figure 6. Pin Locations
Table 5. Pin Function Descriptions
Pin No. Mnemonic Type1 Description
1 DIO3 I/O Configurable Digital Input/Output.
2 DIO4/CLKIN I/O Configurable Digital Input/Output or Sync Clock Input.
3 SCLK I SPI Serial Clock.
4
DOUT
O
SPI Data Output. Clocks the output on the SCLK falling edge.
5 DIN I SPI Data Input. Clocks the input on the SCLK rising edge.
6 CS I SPI Chip Select.
7 DIO1 I/O Configurable Digital Input/Output.
8 RST I Reset.
9
DIO2
I/O
Configurable Digital Input/Output.
10, 11, 12 VDD S Power Supply.
13, 14, 15 GND S Power Ground.
16, 17, 18, 19, 20 DNC N/A Do Not Connect. Do not connect to these pins.
1 S is supply, O is output, I is input, N/A is not applicable.
ADIS16445 Data Sheet
Rev. F | Page 8 of 22
TYPICAL PERFORMANCE CHARACTERISTICS
1000
100
10
1
0.01 0.1 110 10k1k100
ROO T AL LAN VARIANCE (°/ Hou r)
Tau (Seconds)
11051-007
+σ
AVERAGE
–σ
Figure 7. Gyroscope Root Allan Variance
0.01
0.1
1
10
0.01 0.1 110 100 10k
1k
ROO T AL LAN VARIANCE (m g)
Tau (Seconds)
11051-008
AVERAGE
+σ
–σ
Figure 8. Accelerometer Root Allan Variance
Data Sheet ADIS16445
Rev. F | Page 9 of 22
USER REGISTERS
Table 6. User Register Memory Map
Name
R/W
Flash Backup
Address
1
Default
Function
Bit Assignments
FLASH_CNT R Yes 0x00 N/A Flash memory write count See Table 26
Reserved N/A N/A 0x02 N/A N/A N/A
XGYRO_OUT R No 0x04 N/A X-axis gyroscope output See Table 9
YGYRO_OUT R No 0x06 N/A Y-axis gyroscope output See Table 10
ZGYRO_OUT R No 0x08 N/A Z-axis gyroscope output See Table 11
XACCL_OUT R No 0x0A N/A X-axis accelerometer output See Table 13
YACCL_OUT R No 0x0C N/A Y-axis accelerometer output See Table 14
ZACCL_OUT
R
No
0x0E
N/A
Z-axis accelerometer output
See Table 15
Reserved N/A N/A 0x10 to 0x16 N/A Reserved N/A
TEMP_OUT R No 0x18 N/A Temperature output See Table 17
XGYRO_OFF R/W Yes 0x1A 0x0000 X-axis gyroscope bias offset factor See Table 30
YGYRO_OFF R/W Yes 0x1C 0x0000 Y-axis gyroscope bias offset factor See Table 31
ZGYRO_OFF
R/W
Yes
0x1E
0x0000
Z-axis gyroscope bias offset factor
See Table 32
XACCL_OFF R/W Yes 0x20 0x0000 X-axis acceleration bias offset factor See Table 33
YACCL_OFF R/W Yes 0x22 0x0000 Y-axis acceleration bias offset factor See Table 34
ZACCL_OFF R/W Yes 0x24 0x0000 Z-axis acceleration bias offset factor See Table 35
Reserved N/A N/A 0x26 to 0x30 N/A Reserved N/A
GPIO_CTRL R/W No 0x32 0x0000 Auxiliary digital input/output control See Table 27
MSC_CTRL R/W Yes 0x34 0x0006 Miscellaneous control See Table 24
SMPL_PRD R/W Yes 0x36 0x0001 Internal sample period (rate) control See Table 28
SENS_AVG R/W Yes 0x38 0x0402 Dynamic range and digital filter control See Table 29
Reserved N/A N/A 0x3A N/A Reserved N/A
DIAG_STAT R No 0x3C 0x0000 System status See Table 25
Reserved N/A N/A 0x3A N/A Reserved N/A
GLOB_CMD
W
N/A
0x3E
0x0000
System command
See Table 19
ALM_MAG1 R/W Yes 0x40 0x0000 Alarm 1 amplitude threshold See Table 36
ALM_MAG2 R/W Yes 0x42 0x0000 Alarm 2 amplitude threshold See Table 37
ALM_SMPL1 R/W Yes 0x44 0x0000 Alarm 1 sample size See Table 38
ALM_SMPL2 R/W Yes 0x46 0x0000 Alarm 2 sample size See Table 39
ALM_CTRL
R/W
Yes
0x48
0x0000
Alarm control
See Table 40
Reserved N/A N/A 0x4A to 0x51 N/A Reserved N/A
LOT_ID1 R Yes 0x52 N/A Lot identification number See Table 20
LOT_ID2 R Yes 0x54 N/A Lot identification number See Table 21
PROD_ID R Yes 0x56 0x403D Product identifier See Table 22
SERIAL_NUM R Yes 0x58 N/A Lot-specific serial number See Table 23
1 Each register contains two bytes. The address of the lower byte is displayed. The address of the upper byte is equal to the address of the lower byte plus 1.
ADIS16445 Data Sheet
Rev. F | Page 10 of 22
USER INTERFACE
The ADIS16445 is an autonomous system that requires no user
initialization. When it has a valid power supply, it initializes itself
and starts sampling, processing, and loading sensor data into
the output registers at a sample rate of 819.2 SPS. DIO1 pulses
high after each sample cycle concludes. The SPI interface enables
simple integration with many embedded processor platforms,
as shown in Figure 9 (electrical connection) and Table 7 (pin
functions).
SYSTEM
PROCESSOR
SPI MASTER
ADIS16445
SCLK
CS
DIN
DOUT
SCLK
SS
MOSI
MISO
+3.3V
IRQ DIO1
VDD I/O LINESARE COM PATIBLE WITH
3.3V LOGIC LEVELS
10
6
3
5
4
7
11 12
13 14 15
11051-009
Figure 9. Electrical Connection Diagram
Table 7. Generic Master Processor Pin Names and Functions
Pin Name Function
SS Slave select
SCLK Serial clock
MOSI Master output, slave input
MISO Master input, slave output
IRQ Interrupt request
The ADIS16445 SPI interface supports full duplex serial commu-
nication (simultaneous transmit and receive) and uses the bit
sequence shown in Figure 12. Table 8 provides a list of the most
common settings that require attention to initialize the serial
port of a processor for the ADIS16445 SPI interface.
Table 8. Generic Master Processor SPI Settings
Processor Setting Description
Master The ADIS16445 operates as a slave
SCLK Rate ≤ 2 MHz
1
Maximum serial clock rate
SPI Mode 3 CPOL = 1 (polarity), CPHA = 1 (phase)
MSB-First Mode Bit sequence
16-Bit Mode Shift register/data length
1 For burst read, SCLK rate ≤ 1 MHz.
READING SENSOR DATA
The ADIS16445 provides two different options for acquiring
sensor data: a single register and a burst register. A single regis-
ter read requires two 16-bit SPI cycles. The first cycle requests
the contents of a register using the bit assignments in Figure 12.
Bit DC7 to Bit DC0 are don’t cares for a read, and then the output
register contents follow on DOUT during the second sequence.
Figure 10 includes three single register reads in succession.
In this example, the process starts with DIN = 0x0400 to request
the contents of XGYRO_OUT, then follows with 0x0600 to re-
quest YGYRO_OUT, and 0x0800 to request ZGYRO_OUT. Full
duplex operation enables processors to use the same 16-bit SPI
cycle to read data from DOUT while requesting the next set of
data on DIN. Figure 11 provides an example of the four SPI
signals when reading XGYRO_OUT in a repeating pattern.
XGYRO_OUT
DIN
DOUT
YGYRO_OUT ZGYRO_OUT
0x0400 0x0600 0x0800
11051-010
Figure 10. SPI Read Example
SCLK
CS
DIN
DOUT
DOUT = 1111 10011101 1010 = 0xF9DA = –15.74°/sec LSBs ≥ –62.96°/sec
DIN = 0000 0100 0000 0000 = 0x0400
11051-011
Figure 11. Example SPI Read, Second Sequence, SENS_AVG[15:8] = 0x04
R/W R/W
A6 A5 A4 A3 A2 A1 A0 DC7 DC6 DC5 DC4 DC3 DC2 DC1 DC0
D0D1D2D3D4D5D6D7D8D9D10D11D12D13D14D15
CS
SCLK
DIN
DOUT
A6 A5
D13D14D15
NOTES
1. THE DO UT BI T PATTERN REFLECTS THE ENTIRE CONTENTS OF THE REGISTER IDENTIFIED BY [A6:A0]
IN THE PRE V IO US 16- BIT DIN SE QUENCE WHEN R/ W = 0.
2. I F R/ W = 1 DURING THE P RE V IO US S E QUENCE, DO UT IS NOT DE FI NE D.
11051-012
Figure 12. SPI Communication Bit Sequence
Data Sheet ADIS16445
Rev. F | Page 11 of 22
Burst Read Function
The burst read function provides a way to read all of the data in
one continuous stream of bits, with no stall time. As shown in
Figure 13, start this mode by setting DIN = 0x3E00 while keeping
CS low for eight additional 16-bit read cycles. These eight cycles
produce the following sequence of output registers on DOUT:
DIAG_STAT, XGYRO_OUT, YGYRO_OUT, ZGYRO_OUT,
XACCL_OUT, YACCL_OUT, ZACCL_OUT, and TEMP_OUT.
GLOB_CMD
CS
SCLK
DIN
DOUT XGYRO_OUTDIAG_STATTEMP_OUT
11051-013
1 2 3 9
Figure 13. Burst Read Sequence
SPI Read Test Sequence
Figure 14 provides a test pattern for testing the SPI communica-
tion. In this pattern, write 0x5600 to the DIN line in a repeating
pattern and raise chip select for at least 9 µs between each 16-bit
sequence. Starting with the second 16-bit sequence, DOUT
produces the contents of the PROD_ID register, 0x403D (see
Table 22).
DOUT = 0100 0000 0011 1101 = 0x403D = 16, 445
DIN = 0101 0110 0000 0000 = 0x5600
SCLK
CS
DIN
DOUT
11051-014
Figure 14. SPI Test Read Pattern DIN = 0x5600, DOUT = 0x403D
DEVICE CONFIGURATION
The control registers in Table 6 provide users with a variety of
configuration options. The SPI provides access to these registers,
one byte at a time, using the bit assignments in Figure 12. Each
register has 16 bits, where Bits[7:0] represent the lower address,
and Bits[15:8] represent the upper address. Figure 15 provides
an example of writing 0x04 to Address 0x37 (SMPL_PRD[15:8],
using DIN = 0xB704). This example reduces the sample rate by
a factor of eight (see Table 28).
SCLK
CS
DIN
DIN = 10 11 0111 0000 0100 = 0xB704, WRITES 0x04 TO ADDRESS 0x37.
11051-015
Figure 15. Example SPI Write Sequence
Dual Memory Structure
Writing configuration data to a control register updates its SRAM
contents, which are volatile. After optimizing each relevant control
register setting in a system, set GLOB_CMD[3] = 1 (DIN =
0xBE08) to back up these settings in nonvolatile flash memory.
The flash backup process requires a valid power supply level for
the entire process time, 75 ms. Table 6 provides a user register
memory map that includes a flash backup column. A Yes in this
column indicates that a register has a mirror location in flash
and, when backed up properly, it automatically restores itself
during startup or after a reset. Figure 16 provides a diagram of
the dual memory structure used to manage operation and store
critical user settings.
NONVOLATILE
FLASH MEMORY
(NO SPI ACCESS)
MANUAL
FLASH
BACKUP
START-UP
RESET
VOLATILE
SRAM
SPI ACCESS
11051-016
Figure 16. SRAM and Flash Memory Diagram
ADIS16445 Data Sheet
Rev. F | Page 12 of 22
OUTPUT DATA REGISTERS
Each sensor in the ADIS16445 has a dedicated output register
in the user register map (see Table 6). Figure 17 provides ar-
rows, which describe the direction or rotation (gX, gY, gZ) and
acceleration (aX, aY, aZ) that produces a positive response in the
output data.
GYROSCOPES
XGYRO_OUT (see Table 9) contains x-axis gyroscope data (gX
in Figure 17), YGYRO_OUT (see Table 10) contains y-axis gyro-
scope data (gY in Figure 17), and ZGYRO_OUT (see Table 11)
contains z-axis gyroscope data (gZ in Figure 17). Table 12 illus-
trates the gyroscope data format with numerical examples.
Table 9. XGYRO_OUT (Base Address = 0x04), Read Only
Bits Description
[15:0] X-axis gyroscope data, twos complement format,
100 LSB/°/sec (SENS_AVG[15:8] = 0x04), 0°/sec = 0x0000
Table 10. YGYRO_OUT (Base Address = 0x06), Read Only
Bits Description
[15:0]
Y-axis gyroscope data, twos complement format,
100 LSB/°/sec (SENS_AVG[15:8] = 0x04), 0°/sec = 0x0000
Table 11. ZGYRO_OUT (Base Address = 0x08), Read Only
Bits Description
[15:0] Z-axis gyroscope data, twos complement format,
100 LSB/°/sec (SENS_AVG[15:8] = 0x04), 0°/sec = 0x0000
Table 12. Rotation Rate, Twos Complement Format1
Rotation
Rate (°/sec) Decimal Hex Binary
+250
25,000
0x61A8
0110 0001 1010 1000
+2 ÷ 100 +2 0x0002 0000 0000 0000 0010
+1 ÷ 100 +1 0x0001 0000 0000 0000 0001
0 0 0x0000 0000 0000 0000 0000
−1 ÷ 100 −1 0xFFFF 1111 1111 1111 1111
−2 ÷ 100 −2 0xFFFE 1111 1111 1111 1110
−250 −25,000 0x9E58 1001 1110 0101 1000
1 SENS_AVG[15:8] = 0x04, see Table 29.
ACCELEROMETERS
XACCL_OUT (see Table 13) contains x-axis accelerometer data
(aX in Figure 17), YACCL_OUT (see Table 14) contains y-axis
accelerometer data (aY in Figure 17), and ZACCL_OUT (see
Table 15) contains z-axis accelerometer data (aZ in Figure 17).
Table 16 illustrates the accelerometer data format with numerical
examples.
Table 13. XACCL_OUT (Base Address = 0x0A), Read Only
Bits Description
[15:0] X-axis acceleration data, twos complement format,
4000 LSB/g, 0 g = 0x0000
Table 14. YACCL_OUT (Base Address = 0x0C), Read Only
Bits Description
[15:0] Y-axis acceleration data, twos complement format,
4000 LSB/g, 0 g = 0x0000
Table 15. ZACCL_OUT (Base Address = 0x0E), Read Only
Bits Description
[15:0] Z-axis acceleration data, twos complement format,
4000 LSB/g, 0 g = 0x0000
Table 16. Acceleration, Twos Complement Format
Acceleration (g) Decimal Hex Binary
+5 20,000 0x4E20 0100 1110 0010 0000
+2 ÷ 4000 +2 0x0002 0000 0000 0000 0010
+1 ÷ 4000 +1 0x0001 0000 0000 0000 0001
0 0 0x0000 0000 0000 0000 0000
−1 ÷ 4000 −1 0xFFFF 1111 1111 1111 1111
−2 ÷ 4000
−2
0xFFFE
1111 1111 1111 1110
−5 −20,000 0xB1E0 1011 0001 1110 0000
Y-AXIS X-AXIS
Z-AXIS
aZ
aY
gY
aX
gX
gZ
11051-017
Figure 17. Inertial Sensor Direction Reference
Data Sheet ADIS16445
Rev. F | Page 13 of 22
INTERNAL TEMPERATURE
The internal temperature measurement data loads into the
TEMP_OUT (see Table 17) register. Table 18 illustrates the
temperature data format. Note that this temperature represents
an internal temperature reading, which does not precisely rep-
resent external conditions. The intended use of TEMP_OUT is
to monitor relative changes in temperature.
Table 17. TEMP_OUT (Base Address = 0x18), Read Only
Bits
Description
[15:12] Not used
[11:0] Twos complement, 0.07386°C/LSB, 31°C = 0x000
Table 18. Temperature, Twos Complement Format
Temperature (°C) Decimal Hex Binary
+105 +1002 0x3EA 0011 1110 1010
+85 +731 0x2DB 0010 1101 1011
+31.14771 +2 0x002 0000 0000 0010
+31.07386 +1 0x001 0000 0000 0001
+31 0 0x000 0000 0000 0000
+30.92614 −1 0xFFF 1111 1111 1111
+30.85229 −2 0xFFE 1111 1111 1110
−40 −962 0xC3E 1100 0011 1110
ADIS16445 Data Sheet
Rev. F | Page 14 of 22
SYSTEM FUNCTIONS
GLOBAL COMMANDS
The GLOB_CMD register in Table 19 provides trigger bits
for software reset, flash memory management, and calibration
control. Start each of these functions by writing a 1 to the assigned
bit in GLOB_CMD. After completing the task, the bit automati-
cally returns to 0.
For example, set GLOB_CMD[7] = 1 (DIN = 0xBE80) to initiate
a software reset. Set GLOB_CMD[3] = 1 (DIN = 0xBE08) to back
up the user register contents in nonvolatile flash. This sequence
includes loading the control registers with the data in their re-
spective flash memory locations prior to producing new data.
Table 19. GLOB_CMD (Base Address = 0x3E), Write Only
Bits Description (Default = 0x0000)
[15:8] Not used
7 Software reset
[6:4] Not used
3 Flash update
2 Not used
1 Factory calibration restore
0 Gyroscope bias correction
PRODUCT IDENTIFICATION
The PROD_ID register in Table 22 contains the binary equivalent
of 16,445. It provides a product-specific variable for systems that
need to track this in their system software. The LOT_ID1 and
LOT_ID2 registers in Table 20 and Table 21, respectively, combine
to provide a unique, 32-bit lot identification code.
The SERIAL_NUM register in Table 23 contains a binary num-
ber that represents the serial number on the device label. The
assigned serial numbers in SERIAL_NUM are lot specific.
Table 20. LOT_ID1 (Base Address = 0x52), Read Only
Bits Description
[15:0] Lot identification, binary code
Table 21. LOT_ID2 (Base Address = 0x54), Read Only
Bits Description
[15:0] Lot identification, binary code
Table 22. PROD_ID (Base Address = 0x56), Read Only
Bits
Description (Default = 0x403D)
[15:0] Product identification = 0x403D (16,445)
Table 23. SERIAL_NUM (Base Address = 0x58), Read Only
Bits Description
[15:12] Reserved
[11:0] Serial number, 1 to 4094 (0xFFE)
SELF-TEST FUNCTION
The MSC_CTRL register in Table 24 provides a self-test function
for the gyroscopes and accelerometers. This function allows the
user to verify the mechanical integrity of each MEMS sensor.
When enabled, the self-test applies an electrostatic force to each
internal sensor element, which causes them to move. The move-
ment in each element simulates its response to actual rotation/
acceleration and generates a predictable electrical response in the
sensor outputs. Set MSC_CTRL[10] = 1 (DIN = 0xB504) to activate
the internal self-test routine, which compares the response to an
expected range of responses and reports a pass/fail response to
DIAG_STAT[5]. If this bit is high, review DIAG_STAT[15:10]
to identify the failing sensor.
Table 24. MSC_CTRL (Base Address = 0x34), Read/Write
Bits Description (Default = 0x0006)
[15:12] Not used
11 Checksum memory test (cleared upon completion)1
1 = enabled, 0 = disabled
10 Internal self-test (cleared upon completion)1
1 = enabled, 0 = disabled
[9:8] Do not use, always set to 00
7 Not used
6 Point of percussion, see Figure 21
1 = enabled, 0 = disabled
[5:3] Not used
2 Data ready enable
1 = enabled, 0 = disabled
1 Data ready polarity
1 = active high when data is valid
0 = active low when data is valid
0 Data ready line select
1 = DIO2, 0 = DIO1
1 The bit is automatically reset to 0 after finishing the test.
Data Sheet ADIS16445
Rev. F | Page 15 of 22
STATUS/ERROR FLAGS
The DIAG_STAT register in Table 25 provides error flags for
a number of functions. Each flag uses 1 to indicate an error con-
dition and 0 to indicate a normal condition. Reading this register
provides access to the status of each flag and resets all of the bits
to 0 for monitoring future operation. If the error condition remains,
the error flag returns to 1 at the conclusion of the next sample
cycle. The SPI communication error flag in DIAG_STAT[3]
indicates that the number of SCLKs in a SPI sequence did not
equal a multiple of 16 SCLKs.
Table 25. DIAG_STAT (Base Address = 0x3C), Read Only
Bits Description (Default = 0x0000)
15 Z-axis accelerometer self-test failure
1 = fail, 0 = pass
14 Y-axis accelerometer self-test failure
1 = fail, 0 = pass
13 X-axis accelerometer self-test failure
1 = fail, 0 = pass
12 Z-axis gyroscope self-test failure
0 = pass
11 Y-axis gyroscope self-test failure
1 = fail, 0 = pass
10 X-axis gyroscope self-test failure
1 = fail, 0 = pass
9 Alarm 2 status
1 = active, 0 = inactive
8 Alarm 1 status
1 = active, 0 = inactive
7 Not used
6 Flash test, checksum flag
1 = fail, 0 = pass
5 Self-test diagnostic error flag
1 = fail, 0 = pass
4 Sensor overrange
1 = overrange, 0 = normal
3 SPI communication failure
1 = fail, 0 = pass
2 Flash update failure
1 = fail, 0 = pass
[1:0]
Not used
MEMORY MANAGEMENT
The FLASH_CNT register in Table 26 provides a 16-bit counter
that helps track the number of write cycles to the nonvolatile flash
memory. The flash updates every time a manual flash update
occurs. A manual flash update is initiated by the GLOB_CMD[3]
bit and is performed at the completion of the GLOB_CMD[1:0]
functions (see Table 19).
Table 26. FLASH_CNT (Base Address = 0x00), Read Only
Bits
Description
[15:0] Binary counter
Checksum Test
Set MSC_CTRL[11] = 1 (DIN = 0xB508) to perform a check-
sum test of the internal program memory. This function takes
a summation of the internal program memory and compares
it with the original summation value for the same locations
(from factory configuration). If the sum matches the correct val-
ue, DIAG_STAT[6] is equal to 0. If it does not match, DI-
AG_STAT[6] is equal to 1. Make sure that the power supply is
within specification for the entire 20 ms that this function takes
to complete.
ADIS16445 Data Sheet
Rev. F | Page 16 of 22
INPUT/OUTPUT CONFIGURATION
DATA READY INDICATOR
The data ready indicator provides a signal that indicates
when the registers are updating, so that system processors can
avoid data collision, a condition when internal register updates
happen at the same time that an external processor requests it.
The data ready signal has valid and invalid states. Using the
transition from invalid to valid to trigger an interrupt service
routine provides the most time for data acquisition (before
the next register update). See Figure 4 and Table 2 for specific
timing information.
MSC_CTRL[2:0] (see Table 24) provide control bits for ena-
bling this function, selecting the polarity of the valid state and
I/O line assignment (DIO1, DIO2). The factory default setting
of MSC_CTRL[2:0] = 110 establishes DIO1 as a data ready out-
put line and assigns the valid state with a logic high (1). Set
MSC_CTRL[2:0] = 100 (DIN = 0xB404) to change the polarity of
the data ready signal on DIO1 for interrupt inputs that require
negative logic inputs for activation.
GENERAL-PURPOSE INPUT/OUTPUT
DIO1, DIO2, DIO3, and DIO4 are configurable, general-purpose
input/output lines that serve multiple purposes. The data
ready controls in MSC_CTRL[2:0] have the highest priority
for configuring DIO1 and DIO2. The alarm indicator controls in
ALM_CTRL[2:0] have the second highest priority for configuring
DIO1 and DIO2. The external clock control associated with
SMPL_PRD[0] has the highest priority for DIO4 configuration
(see Table 28). GPIO_CTRL in Table 27 has the lowest priority
for configuring DIO1, DIO2, and DIO4, and has absolute con-
trol over DIO3.
Table 27. GPIO_CTRL (Base Address = 0x32), Read/Write
Bits Description (Default = 0x0000)
[15:12] Not used
11 General-Purpose I/O Line 4 (DIO4) data level
10 General-Purpose I/O Line 3 (DIO3) data level
9 General-Purpose I/O Line 2 (DIO2) data level
8 General-Purpose I/O Line 1 (DIO1) data level
[7:4] Not used
3 General-Purpose I/O Line 4 (DIO4) direction control
1 = output, 0 = input
2 General-Purpose I/O Line 3 (DIO3) direction control
1 = output, 0 = input
1 General-Purpose I/O Line 2 (DIO2) direction control
1 = output, 0 = input
0 General-Purpose I/O Line 1 (DIO1) direction control
1 = output, 0 = input
Example Input/Output Configuration
For example, set GPIO_CTRL[3:0] = 0100 (DIN = 0xB204)
to set DIO3 as an output signal pin and DIO1, DIO2, and
DIO4 as input signal pins. Set the output on DIO3 to 1 by set-
ting GPIO_CTRL[10] = 1 (DIN = 0xB304). Then, read
GPIO_CTRL[7:0] (DIN = 0x3200) and mask off GPIO_CTRL[9:8]
and GPIO_CTRL[11] to monitor the digital signal levels on
DIO4, DIO2, and DIO1.
Data Sheet ADIS16445
Rev. F | Page 17 of 22
DIGITAL PROCESSING CONFIGURATION
GYROSCOPES/ACCELEROMETERS
Figure 19 provides a diagram that describes all signal processing
components for the gyroscopes and accelerometers. The internal
sampling system produces new data in the xGYRO_OUT and
xACCL_OUT output data registers at a rate of 819.2 SPS. The
SMPL_PRD register in Table 28 provides two functional controls
that affect sampling and register update rates. SMPL_PRD[12:8]
provides a control for reducing the update rate, using an averaging
filter with a decimated output. These bits provide a binomial
control that divides the data rate by a factor of 2 every time this
number increases by 1. For example, set SMPL_PRD[15:8] =
0x04 (DIN = 0xB704) to set the decimation factor to 16. This
reduces the update rate to 51.2 SPS and the bandwidth to
~25 Hz. The SMPL_PRD[12:8] setting affects the update rate
for the TEMP_OUT register (see Table 17) as well.
Table 28. SMPL_PRD (Base Address = 0x36), Read/Write
Bits Description (Default = 0x0001)
[15:13] Not used
[12:8] D, decimation rate setting, binomial, see Figure 19
[7:1] Not used
0 Clock
1 = internal sampling clock, 819.2 SPS
0 = external sampling clock
INPUT CLOCK CONFIGURATION
SMPL_PRD[0] (see Table 28) provides a control for synchroniz-
ing the internal sampling to an external clock source. Set
SMPL_PRD[0] = 0 (DIN = 0xB600) and GPIO_CTRL[3] = 0
(DIN = 0xB200) to enable the external clock. See Table 2 and
Figure 4 for timing information.
Digital Filtering
The SENS_AVG register in Table 29 provides user controls for
the low-pass filter. This filter contains two cascaded averaging
filters that provide a Bartlett window, FIR filter response (see
Figure 19). For example, set SENS_AVG[2:0] = 100 (DIN = 0xB804)
to set each stage to 16 taps. When used with the default sample
rate of 819.2 SPS and zero decimation (SMPL_PRD[15:8] = 0x00),
this value reduces the sensor bandwidth to approximately 16 Hz.
0
–20
–40
–60
–80
–100
–120
–140
0.001 0.01 0.1 1
MAG NITUDE ( dB)
FREQUENCY (f/f
S
)
N = 2
N = 4
N = 16
N = 64
11051-018
Figure 18. Bartlett Window, FIR Filter Frequency Response
(Phase Delay = N Samples)
Dynamic Range
The SENS_AVG[10:8] bits provide three dynamic range
settings for the gyroscopes. The lower dynamic range settings
(±62.5°/sec and ±125°/sec) limit the minimum filter tap sizes
to maintain resolution. For example, set SENS_AVG[10:8] =
010 (DIN = 0xB902) for a measurement range of ±125°/sec.
Because this setting can influence the filter settings, program
SENS_AVG[10:8] before programming SENS_AVG[2:0] if more
filtering is required.
Table 29. SENS_AVG (Base Address = 0x38), Read/Write
Bits Description (Default = 0x0402)
[15:11] Not used
[10:8] Measurement range (sensitivity) selection
100 = ±250°/sec (default condition)
010 = ±125°/sec, filter taps ≥ 4 (Bits[2:0] ≥ 0x02)
001 = ±62.5°/sec, filter taps ≥ 16 (Bits[2:0] ≥ 0x04)
[7:3] Not used
[2:0]
Filter Size Variable B
Number of taps in each stage; NB = 2B
See Figure 18 for filter response
MEMS
SENSOR
LOW-PASS
FILTER
330Hz
CLOCK
819.2SPS
ADC
BARTLETT WINDOW
FIR FILTER
AVERAGE/
DECIMATION
FILTER
EXTERNAL CLOCK E NABLED
BY SMPL_PRD[0] = 0
GYROSCOPES
LOW-PASS, T WO - P OL E (404Hz, 757Hz )
ACCELEROMETERS
LOW-PASS, SINGLE-PO L E (330Hz)
B = SENS_AVG[2:0]
N
B
= 2
B
N
B
= NUMBER OF TAPS
(PER STAGE)
D = SM PL_PRD[ 12: 8]
N
D
= 2
D
N
D
= NUMBER OF TAPS
÷N
D
x(n)
n = 1
1N
B
N
B
x(n)
n = 1
1N
B
N
B
x(n)
n = 1
1N
D
N
D
11051-019
Figure 19. Sampling and Frequency Response Block Diagram
ADIS16445 Data Sheet
Rev. F | Page 18 of 22
CALIBRATION
The mechanical structure and assembly process of the ADIS16445
provide excellent position and alignment stability for each sensor,
even after subjected to temperature cycles, shock, vibration, and
other environmental conditions. The factory calibration includes a
dynamic characterization of each gyroscope and accelerometer over
temperature and generates sensor specific correction formulas.
GYROSCOPES
The XGYRO_OFF (see Table 30), YGYRO_OFF (see Table 31),
and ZGYRO_OFF (see Table 32) registers provide user-
programmable bias adjustment function for the x-, y-, and
z-axis gyroscopes, respectively. Figure 20 illustrates that they con-
tain bias correction factors that adjust to the sensor data imme-
diately before it loads into the output register.
xGYRO_OFF
xACCL_OFF
MEMS
SENSOR ADC FACTORY
CALIBRATION
AND
FILTERING
xGYRO_OUT
xACCL_OUT
11051-020
Figure 20. User Calibration, Gyroscopes, and Accelerometers
Gyroscope Bias Error Estimation
Any system level calibration function must start with an estimate
of the bias errors, which typically comes from a sample of gyro-
scope output data, when the device is not in motion. The sample
size of data depends on the accuracy goals. Figure 7 provides a
trade-off relationship between averaging time and the expected
accuracy of a bias measurement. Vibration, thermal gradients,
and power supply instability can influence the accuracy of this
process.
Table 30. XGYRO_OFF (Base Address = 0x1A), Read/Write
Bits Description (Default = 0x0000)
[15:0] X-axis, gyroscope offset correction factor,
twos complement, 0.0025°/sec/LSB, 0°/sec = 0x0000
Table 31. YGYRO_OFF (Base Address = 0x1C), Read/Write
Bits Description (Default = 0x0000)
[15:0] Y-axis, gyroscope offset correction factor,
twos complement, 0.0025°/sec/LSB, 0°/sec = 0x0000
Table 32. ZGYRO_OFF (Base Address = 0x1E), Read/Write
Bits Description (Default = 0x0000)
[15:0] Z-axis, gyroscope offset correction factor,
twos complement, 0.0025°/sec/LSB, 0°/sec = 0x0000
Gyroscope Bias Correction Factors
When the bias estimate is complete, multiply the estimate by
−1 to change its polarity, convert it into digital format for the
offset correction registers (see Table 30, Table 31, and Table 32),
and write the correction factors to the correction registers. For
example, lower the x-axis bias by 10 LSB (0.025°/sec) by setting
XGYRO_OFF = 0x1FF6 (DIN = 0x9B1F, 0x9AF6).
Single Command Bias Correction
GLOB_CMD[0] (see Table 19) loads the xGYRO_OFF registers
with the values that are the opposite of the values that are in
xGYRO_OUT, at the time of initiation. Use this command, to-
gether with the decimation filter (SMPL_PRD[12:8], see Table 28),
to automatically average the gyroscope data and improve the
accuracy of this function, as follows:
1. Set SENS_AVG[10:8] = 001 (DIN = 0xB901) to optimize
the xGYRO_OUT sensitivity to 0.0025°/sec/LSB.
2. Set SMPL_PRD[12:8] = 0x10 (DIN = 0xB710) to set the
decimation rate to 65,536 (216), which provides an averaging
time of 80 seconds (65,536 ÷ 819.2 SPS).
3. Wait for 80 seconds while keeping the device motionless.
4. Set GLOB_CMD[0] = 1 (DIN = 0xBE01) and wait for the
time it takes to perform the flash memory backup.
ACCELEROMETERS
The XACCL_OFF (see Table 33), YACCL _OFF (see Table 34),
and ZACCL_OFF (see Table 35) registers provide user pro-
grammable bias adjustment function for the x-, y-, and
z-axis accelerometers, respectively. These registers adjust the
accelerometer data in the same manner as XGYRO_OFF in
Figure 20.
Table 33. XACCL_OFF (Base Address = 0x20), Read/Write
Bits Description (Default = 0x0000)
[15:0] X-axis, accelerometer offset correction factor,
twos complement, 0.25 mg/LSB, 0 g = 0x0000
Table 34. YACCL_OFF (Base Address = 0x22), Read/Write
Bits Description (Default = 0x0000)
[15:14] Not used
[13:0] Y-axis, accelerometer offset correction factor,
twos complement, 0.25 mg/LSB, 0 g = 0x0000
Table 35. ZACCL_OFF (Base Address = 0x24), Read/Write
Bits Description (Default = 0x0000)
[15:14] Not used
[13:0] Z-axis, accelerometer offset correction factor,
twos complement, 0.25 mg/LSB, 0 g = 0x0000
Accelerometer Bias Error Estimation
Under static conditions, orient each accelerometer in positions
where the response to gravity is predictable. A common approach
is to measure the response of each accelerometer when they are
oriented in peak response positions, that is, where ±1 g is the
ideal measurement position. Next, average the +1 g and −1 g
accelerometer measurements together to estimate the residual
bias error. Using more points in the rotation can improve the
accuracy of the response.
Data Sheet ADIS16445
Rev. F | Page 19 of 22
Accelerometer Bias Correction Factors
When the bias estimate is complete, multiply the estimate by
−1 to change its polarity, convert it to the digital format for the
offset correction registers (see Table 33, Table 34 or Table 35),
and write the correction factors to the correction registers. For
example, lower the x-axis bias by 12 LSB (3 mg) by setting
XACCL_OFF = 0xFFF4 (DIN = 0xA1FF, 0xA0F4).
Point of Percussion Alignment
Set MSC_CTRL[6] = 1 (DIN = 0xB446) to enable this feature
and maintain the factory default settings for DIO1. This feature
performs a point of percussion translation to the point identified
in Figure 21. See Table 24 for more information on MSC_CTRL.
ORIGINALIGNMENT
REF E RE NCE POI NT
SEE MSC_CTRL[6].
11051-021
Figure 21. Point of Percussion Physical Reference
FLASH UPDATES
When using the user calibration registers to optimize system
level accuracy, set GLOB_CMD[3] = 1 (DIN = 0xBE04) to save
these settings in nonvolatile flash memory. Be sure to consider
the endurance rating of the flash memory when determining how
often to update the user correction factors in the flash memory.
RESTORING FACTORY CALIBRATION
Set GLOB_CMD[1] = 1 (DIN = 0xBE02) to execute the factory
calibration restore function, which resets the gyroscope and accel-
erometer offset registers to 0x0000 and all sensor data to 0. Then, it
automatically updates the flash memory and restarts sampling and
processing data. See Table 19 for information on GLOB_CMD.
ADIS16445 Data Sheet
Rev. F | Page 20 of 22
ALARMS
Alarm 1 and Alarm 2 provide two independent alarms with
programmable levels, polarity, and data sources.
STATIC ALARM USE
The static alarms setting compares the data source selection
(ALM_CTRL[15:8]) with the values in the ALM_MAGx registers
listed in Table 36 and Table 37, using ALM_MAGx[15] to deter-
mine the trigger polarity. The data format in these registers
matches the format of the data selection in ALM_CTRL[15:8].
See Table 41, Alarm 1, for a static alarm configuration example.
Table 36. ALM_MAG1 (Base Address = 0x40), Read/Write
Bits Description (Default = 0x0000)
[15:0] Threshold setting; matches for format of
ALM_CTRL[11:8] output register selection
Table 37. ALM_MAG2 (Base Address = 0x42), Read/Write
Bits Description (Default = 0x0000)
[15:0] Threshold setting; matches for format of
ALM_CTRL[15:12] output register selection
DYNAMIC ALARM USE
The dynamic alarm setting monitors the data selection for a
rate-of-change comparison. The rate-of-change comparison is
represented by the magnitude in the ALM_MAGx registers over
the time represented by the number-of-samples setting in the
ALM_SMPLx registers, located in Table 38 and Table 39. See
Table 41, Alarm 2, for a dynamic alarm configuration example.
Table 38. ALM_SMPL1 (Base Address = 0x44), Read/Write
Bits Description (Default = 0x0000)
[15:8] Not used
[7:0] Binary, number of samples (both 0x00 and 0x01 = 1)
Table 39. ALM_SMPL2 (Base Address = 0x46), Read/Write
Bits Description (Default = 0x0000)
[15:8] Not used
[7:0] Binary, number of samples (both 0x00 and 0x01 = 1)
ALARM REPORTING
The DIAG_STAT[9:8] bits provide error flags that indicate an
alarm condition. The ALM_CTRL[2:0] bits provide controls
for a hardware indicator using DIO1 or DIO2.
Table 40. ALM_CTRL (Base Address = 0x48), Read/Write
Bits Description (Default = 0x0000)
[15:12] Alarm 2 data source selection
0000 = disable
0001 = XGYRO_OUT
0010 = YGYRO_OUT
0011 = ZGYRO_OUT
0100 = XACCL_OUT
0101 = YACCL_OUT
0110 = ZACCL_OUT
[11:8] Alarm 1 data source selection (same as Alarm 2)
7 Alarm 2, dynamic/static (1 = dynamic, 0 = static)
6
Alarm 1, dynamic/static (1 = dynamic, 0 = static)
5 Alarm 2, polarity (1 = greater than ALM_MAG2)
4 Alarm 1, polarity (1 = greater than ALM_MAG1)
3 Data source filtering (1 = filtered, 0 = unfiltered)
2 Alarm indicator (1 = enabled, 0 = disabled)
1 Alarm indicator active polarity (1 = high, 0 = low)
0 Alarm output line select (1 = DIO2, 0 = DIO1)
Alarm Example
Table 41 offers an example that configures Alarm 1 to trigger when
filtered ZACCL_OUT data drops below 0.7 g, and Alarm 2 to
trigger when filtered ZGYRO_OUT data changes by more than
50°/sec over a 100 ms period, or 500°/sec2. The filter setting
helps reduce false triggers from noise and refines the accuracy
of the trigger points. The ALM_SMPL2 setting of 82 samples
provides a comparison period that is approximately equal to
100 ms for an internal sample rate of 819.2 SPS.
Table 41. Alarm Configuration Example
DIN Description
0xC936, ALM_CTRL = 0x36AF
0xC8AF Alarm 2: dynamic, Δ-ZGYRO_OUT
(Δ-time, ALM_SMPL2) > ALM_MAG2
Alarm 1: static, ZACCL_OUT < ALM_MAG1, filtered data
DIO2 output indicator, positive polarity
0xC313,
0xC288
ALM_MAG2 = 0x1388 = 5000 LSB = 50°/sec
0xC10A,
0xC0F0
ALM_MAG1 = 0x0AF0 = 2800 LSB = 0.7 g
0xC652 ALM_SMPL2[7:0] = 0x52 = 82 samples
82 samples ÷ 819.2 SPS = ~100 ms
Data Sheet ADIS16445
Rev. F | Page 21 of 22
APPLICATIONS INFORMATION
MOUNTING TIPS
The mounting and installation process can influence gyroscope
bias repeatability and other key parametric behaviors. To pre-
serve the best performance, use the following guidelines when
developing an attachment approach for the ADIS16445:
• Focus mounting force at the machine screw locations.
• Avoid direct force application on the substrate.
• Avoid placing mounting pressure on the package lid, except
for the edges that border the exposed side of the substrate.
• Use a consistent mounting torque of 28 inch-ounces on
mounting hardware.
• Avoid placing translational forces on the electrical connector.
For more ideas on mounting ideas and tips, please refer to
Application Note AN-1305.
POWER SUPPLY CONSIDERATIONS
The power supply must be within 3.15 V and 3.45 V for normal
operation and optimal performance. During start up, the internal
power conversion system starts drawing current when VDD
reaches 1.6 V. The internal processor begins initializing when
VDD is equal to 2.35 V. After the processor starts, VDD must
reach 2.7 V within 128 ms. Also, make sure that the power sup-
ply drops below 1.6 V to shut the device down. Figure 9 shows a
10 µF capacitor on the power supply. Using this capacitor sup-
ports optimal noise performance in the sensors.
ADIS16445/PCBZ
The ADIS16445/PCBZ includes one ADIS16445BMLZ, one
interface PCB, and one flexible connector/cable. This particular
flexible cable mates the ADIS16445BMLZ 20-pin connector to
systems that presently support the 24-pin interface from other
products in this family, such as the ADIS16365, ADIS16375,
and ADIS16488A. This combination of components enables
quicker installation for prototype evaluation and algorithm
development. Figure 22 provides a mechanical design example
for using these three components in a system.
ADIS16445BMLZ
INTERFACE PCB
33.40mm 23.75mm
20.15mm
30.10mm
10.07mm
15.05mm
J1 1
11
1
11
12
2
12
2J2
NOTES
1. USE FO UR M 2 M ACHINE S CRE WS TO ATTACH THE ADIS16445.
2. USE FO UR M 3 M ACHINE S CRE WS TO ATTACH THE INTERFACE PCB.
FLEXIBLE CONNECTOR/CABLE
15mm TO
45mm
11051-022
Figure 22. Physical Diagram for Mounting the ADIS16445/PCBZ
Figure 23 provides the pin assignments for the interface board.
12
34
56
78
910
1112
DNC
DNC
DNC
DNC
DIO2
DNC
DNC
DIO1
DIO4
DIO3
GND
J2
GND
2
4
6
8
10
1
3
5
7
9
11 12
RST
CS
GND
GND
VDD
GND
VDD
VDD
DIN
DOUT
SCLK
J1
DNC
11051-023
Figure 23. J1/J2 Pin Assignments for Interface PCB
Installation
The following steps provide an example installation process for
using these three components:
• Drill and tap M2 and M3 holes in the system frame, according
to the locations in Figure 22.
• Install the ADIS16445 using M2 machine screws. Use a
mounting torque of 25 inch-ounces.
• Install the interface PCB using M3 machine screws.
• Connect J1 on the interface flex to the ADIS16445BMLZ
connector.
• Connect J2 on the interface flex to J3 on the interface PCB.
Note that J2 (interface flex) has 20 pins and J3 (interface PCB)
has 24 pins. Make sure that Pin 1 on J2 (interface flex)
connects to Pin 20 on J3 (interface PCB). J3 has a Pin 1 in-
dicator to help guide this connection.
• Use J1 and J2 on the interface PCB to make the electrical
connection with the system supply and embedded pro-
cessor, using 12-pin, 1 mm ribbon cables. The following
parts may be useful in building this type of cable: 3M
Part Number 152212-0100-GB (ribbon crimp connector)
and 3M Part Number 3625/12 (ribbon cable).
The C1/C2 pads on the interface PCB do not have capacitors
on them, but these pads can support the suggested power sup-
ply capacitor of 10 µF (see Figure 9).
PC-BASED EVALUATION TOOLS
The EVA L -ADIS supports PC-based evaluation of the ADIS16445.
Go to www.analog.com/EVAL-ADIS, to download the user guide
(UG-287) and software (IMU evaluation).
ADIS16445 Data Sheet
Rev. F | Page 22 of 22
OUTLINE DIMENSIONS
02-072-2013-B
TOP VIEW
END VIEW
33.40
BSC
30.10
BSC
2.84 BSC
(Pi n Hei ght )
5.18 BSC
(PCB to Connect or )
19.55 BSC
12.50 BSC
0.66
BSC
2.00 BSC
2.30 BSC
(2 PLCS)
2.30 BSC
(2 PLCS)
1.00
BSC
2.00
BSC
7.57
BSC
10.23
BSC
1.00 BSC
PITCH
20.150
BSC
11.10
10.80
10.50
7.89
7.63
7.37
4.70
4.50
4.30
2.96
2.70
2.44
38.08
37.70
37.32
24.53
24.15
23.77 2. 60
Ø2.40
2.20
(4 PLCS)
Figure 24. 20-Lead Module with Connector Interface [MODULE]
(ML-20-3)
Dimensions shown in millimeters
ORDERING GUIDE
Model1 Temperature Range Package Description Package Option
ADIS16445BMLZ −40°C to +105°C 20-Lead Module with Connector Interface [MODULE] ML-20-3
ADIS16445/PCBZ Interface PCB
1 Z = RoHS Compliant Part.
©2012–2015 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D11051-0-12/15(F)
