ams AS5048A-HTSP Magnetic rotary encoder 14-bit angular position sensor Datasheet

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AS5048A/AS5048B
Datasheet
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Magnetic Rotary Encoder
14-bit Angular Position Sensor
General Description
The AS5048 is an easy to use 360° angle position sensor with a 14-bit high resolution output. The maximum system
accuracy is 0.05° assuming linearization and averaging is done by the external microcontroller.
The IC measures the absolute position of the magnet’s rotation angle and consists of Hall sensors, analog digital
converter and digital signal processing. The zero position can be programmed via SPI or I²C command. Therefore no
programmer is needed anymore. This simplifies the assembly of the complete system because the zero position of
the magnet does not need to be mechanically aligned. This helps developers to shorten their developing time. The
sensor tolerates misalignment, air gap variations, temperature variations and as well external magnetic fields. This
robustness and wide temperature range (-40°C up to +150°C) of the AS5048 makes the IC ideal for rotation angle
sensing in harsh industrial and medical environments. Several AS5048 ICs can be connected in daisy chain for serial
data read out. The absolute position information of the magnet is directly accessible over a PWM output and can be
read out over a standard SPI or a high speed I²C interface. AS5048A has a SPI interface, AS5048B I2C interface.
Both devices offer a PWM output. An internal voltage regulator allows the AS5048 to operate at either 3.3 V or 5 V
supplies.
Applications
Key Features & Benefits
• Robotic joint position detection
• Industrial motor position control
• Medical robots and fitness equipment
Block Diagram
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360° contactless angle position sensor
Standard SPI or high speed I²C interface
Pulse width modulated output (PWM)
Simple programmable zero position via SPI or I²C
command
No programmer needed
14-bit full scale resolution
0.0219°/LSB
Angle accuracy 0.05°after system linearization and
averaging
Daisy chain capability
Tolerant to air gap variations
magnetic field input range: 30mT – 70mT
-40°C to +150°C ambient temperature range
3.3V / 5V compliant
14-pin TSSOP package (5x6.4mm)
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AS5048A/AS5048B
Datasheet
Magnetic Rotary Encoder
14-bit Angular Position Sensor
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Contents
GENERAL DESCRIPTION .................................................................................................................. 1
PIN CONFIGURATION ................................................................................................................. 5
1.1
2
P IN D ESCRIPTION ........................................................................................................................ 5
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K EY F EATURES & B ENEFITS .................................................................................................................. 1
A PPLICATIONS ..................................................................................................................................... 1
B LOCK D IAGRAM ................................................................................................................................. 1
ELECTRICAL CHARACTERISTICS ............................................................................................ 6
2.1
2.2
2.3
2.4
2.5
A BSOLUTE M AXIMUM R ATINGS .................................................................................................... 6
O PERATING C ONDITIONS ............................................................................................................. 7
DC/AC C HARACTERISTICS FOR DIGITAL INPUTS AND OUTPUTS ....................................................... 7
E LECTRICAL S YSTEM S PECIFICATIONS .......................................................................................... 8
G LOBAL T IMING C ONDITIONS ...................................................................................................... 8
3
FUNCTIONAL DESCRIPTION ...................................................................................................... 9
4
OPERATION .................................................................................................................................. 9
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4.1 S UPPLY V OLTAGE C ONFIGURATION .............................................................................................. 9
4.2 SPI I NTERFACE ......................................................................................................................... 10
4.2.1 SPI Interface Signals (4-Wire Mode, Wire_mode = 1) .......................................................... 10
4.2.2 SPI Timing ......................................................................................................................... 11
4.2.3 SPI Connection to the Host UC ........................................................................................... 12
4.2.4 SPI Communication Command Package .............................................................................. 13
4.2.5 Read Package (Value Read from AS5048A) ......................................................................... 14
4.2.6 Write Data Package (Value Written to AS5048A) ................................................................. 14
4.2.7 Register Map SPI ............................................................................................................... 15
4.2.8 SPI Interface Commands .................................................................................................... 16
4.3 I²C INTERFACE .......................................................................................................................... 19
4.3.1 I²C Electrical Specification ................................................................................................ 19
4.3.2 I²C Timing ......................................................................................................................... 20
4.3.3 Register Table .................................................................................................................... 21
4.3.4 I²C Slave address ............................................................................................................... 22
4.4 PWM INTERFACE ...................................................................................................................... 22
5
PACKAGE DRAWINGS AND MARKINGS ................................................................................. 23
5.1.1
6
Assembly Lot Code ............................................................................................................. 23
APPLICATION INFORMATION ................................................................................................. 25
6.1 P ROGRAMMING OF THE AS5048 ................................................................................................. 25
6.1.1 Programming of the zero position ....................................................................................... 25
6.1.2 Programming sequence with verification ............................................................................. 25
6.2 D IAGNOSTIC FUNCTIONS OF THE AS5048 .................................................................................... 25
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AS5048A/AS5048B
Datasheet
Magnetic Rotary Encoder
14-bit Angular Position Sensor
C HOOSING THE P ROPER M AGNET ............................................................................................... 26
P HYSICAL P LACEMENT OF THE M AGNET ..................................................................................... 27
M AGNET P LACEMENT ................................................................................................................ 27
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6.3
6.4
6.5
7
ORDERING INFORMATION ...................................................................................................... 28
8
REVISION HISTORY .................................................................................................................. 28
9
COPYRIGHTS .............................................................................................................................. 29
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10 DISCLAIMER .............................................................................................................................. 29
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List of Figures
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F IGURE 1: P IN CONFIGURATION TSSOP14 ................................................................................................. 5
F IGURE 2: C ONNECTIONS FOR 5V AND 3.3V SUPPLY VOLTAGES .................................................................. 9
F IGURE 3 SPI C ONNECTION AS5048A WITH U C ...................................................................................... 10
F IGURE 4 SPI C OMMAND /R ESPONSE D ATA F LOW .................................................................................... 10
F IGURE 5 SPI T IMING D IAGRAM ............................................................................................................. 11
F IGURE 6 S INGLE S LAVE M ODE .............................................................................................................. 12
F IGURE 7 M ULTIPLE S LAVE , N +3 W IRE (S EPARATE C HIP S ELECT ) ............................................................. 12
F IGURE 8 D AISY C HAIN , 4 W IRE ............................................................................................................ 13
F IGURE 9 READ C OMMAND ................................................................................................................... 16
F IGURE 10 WRITE C OMMAND ............................................................................................................... 16
F IGURE 11 CLEAR ERROR FLAG C OMMAND ........................................................................................ 17
F IGURE 12 NOP C OMMAND ................................................................................................................... 18
F IGURE 13 S LAVE ADDRESS CONSTRUCTION ............................................................................................ 22
F IGURE 14 PWM F ORMAT ...................................................................................................................... 23
F IGURE 15 P ACKAGE M ARKING .............................................................................................................. 23
F IGURE 16: T YPICAL MAGNET AND MAGNETIC FLUX DISTRIBUTION ........................................................... 26
F IGURE 17: D EFINED CHIP CENTER AND MAGNET DISPLACEMENT RADIUS .................................................. 27
F IGURE 18: V ERTICAL PLACEMENT OF THE MAGNET ................................................................................. 27
1: P IN DESCRIPTION TSSOP14 ....................................................................................................... 5
2 A BSOLUTE M AXIMUM R ATINGS .................................................................................................. 6
3: O PERATING C ONDITION ............................................................................................................. 7
4:DC/AC CHARACTERISTICS ......................................................................................................... 7
5 S YSTEM SPECIFICATION .............................................................................................................. 8
6 G LOBAL TIMING CONDITIONS ...................................................................................................... 8
7 SPI T IMING C HARACTERISTICS ................................................................................................. 11
8 SPI C OMMAND P ACKAGE ......................................................................................................... 13
9 SPI READ PACKAGE .................................................................................................................. 14
10 SPI WRITE DATA PACKAGE ...................................................................................................... 14
11 SPI REGISTER MAP ................................................................................................................. 15
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T ABLE
T ABLE
T ABLE
T ABLE
T ABLE
T ABLE
T ABLE
T ABLE
T ABLE
T ABLE
T ABLE
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List of Tables
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AS5048A/AS5048B
Datasheet
Magnetic Rotary Encoder
14-bit Angular Position Sensor
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12 C LEAR E RROR F LAG C OMMAND .............................................................................................. 17
13 NOP C OMMAND ..................................................................................................................... 18
14 I²C E LECTICAL S PECIFICATION ............................................................................................... 19
15 I²C T IMING ............................................................................................................................ 20
16 R EGISTER M AP I2C ................................................................................................................ 21
17 PWM P ERIOD AND RESOLUTION .............................................................................................. 23
18: O RDERING I NFORMATION ...................................................................................................... 28
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T ABLE
T ABLE
T ABLE
T ABLE
T ABLE
T ABLE
T ABLE
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AS5048A/AS5048B
Datasheet
Magnetic Rotary Encoder
14-bit Angular Position Sensor
Pin Configuration
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1
Figure 1: Pin configuration TSSOP14
1.1
Pin
Pin Description
AS5048A
Type
Description
AS5048B
Type
Description
1
CSn
DI_ST
SPI chip select - active low
SDA
2
CLK
DI_ST
SPI clock input
SCL
DI_ST
I2C clock input
3
MISO
A2
DI_ST
I2C address selection pin 3
4
MOSI
DI_ST
A1
DI_ST
I2C address selection pin 4
5
TEST
AIO
Test pin, see Note
6
TEST
AIO
Test pin, see Note
7
TEST
AIO
Test pin, see Note
8
TEST
AIO
Test pin, see Note
9
TEST
AIO
Test pin, see Note
AIO
Test pin, see Note
TEST
11
VDD5V
12
VDD3V
GND
14
PWM
S
DO
S
AIO
DI_ST
DO
DIO _ST
DIO _OD
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PIN Types:
S
Same as AS5048A
Positive Supply Voltage, 3.0 to 5.5 V
3.3V Regulator output; internally regulated
from VDD. Connect to VDD for 3V supply
voltage. 10µF capacitor to GND required in
5V operation mode
Negative Supply Voltage (GND)
Pulse Width Modulation output
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13
S
SPI master out/slave in
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10
DIO_ST SPI master in/slave out
DIO_OD Data pin I2C interface
...
...
…
...
...
...
Table 1: Pin description TSSOP14
supply pad
analog I/O
digital input with schmitt trigger
digital output – push-pull
digital I/O with schmitt trigger in the input path
digital I/O with open drain output
Note: Pin 5, 6, 7, 8, 9, 10 should be grounded to GND.
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AS5048A/AS5048B
Datasheet
Magnetic Rotary Encoder
14-bit Angular Position Sensor
2
Absolute Maximum Ratings
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2.1
Electrical Characteristics
Symbol
Min
Max
Unit
DC supply voltage at VDD pin
VDD5V
-0.3
7
V
DC voltage at VDD3V pin
VDD3V
-0.3
5
V
GND
-0.3
0.3
V
VDD+0.3
V
100
mA
Norm: Jedec 78
Norm: MIL 883 E method 3015
DC voltage at GND pin
Input pin voltage
V_in
Input current (latchup immunity)
I_scr
Electrostatic discharge
ESD
+/-2
kV
P_t
150
mW
150
°C
Total power dissipation (all supplies and
outputs)
Storage temperature
T_strg
Package body temperature
Humidity non-condensing
-100
-55
T_body
H
MSL
5
260
°C
85
%
3
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Moisture Sensitive Level
Note
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Parameter
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Stresses beyond those listed under “Absolute Maximum Ratings“ may cause permanent damage to the device. These are stress ratings only. Functional operation of
the device at these or any other conditions beyond those indicated under “Operating Conditions” is not implied. Exposure to absolute maximum rating conditions for
extended periods may affect device reliability.
The reflow peak soldering
temperature (body
temperature)specified is in
accordance with IPC/JEDEC JSTD-020 “Moisture Solid State
Surface Mount Devices”. The lead
finish from Pb-free leaded
packages is matte tin (100% Sn)
Represents a maximum floor life
time of 168h
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Table 2 Absolute Maximum Ratings
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AS5048A/AS5048B
Datasheet
Magnetic Rotary Encoder
14-bit Angular Position Sensor
2.2
Operating Conditions
Symbol
Min
Max
Unit
Positive supply voltage
VDD5V
4.5
5.5
V
5V Operation via LDO
VDD3V
3
3.6
V
LDO output voltage
VDDCORE
3
3.6
V
GND
0
0
V
T_amb
-40
150
°C
15
mA
Ambient temperature
Supply Current
Only for 5V operation.
T_amb_max for 3V is 125°C
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Negative supply voltage
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Parameter
Positive core supply voltage
Note
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All in this specification defined tolerances for external components need to be assured over the whole operation conditions
range and also over lifetime.
I_sup
Table 3: Operating Condition
2.3
DC/AC Characteristics for digital inputs and outputs
Parameter
Symbol
Min
CMOS digital input with schmitt trigger: CSn, CLK, MOSI
High level input voltage
V_IH
0.7 * VDD5V
Low level input voltage
Input leakage current
CMOS output: PWM, MISO
High level output voltage
Capacitive load
Unit
V
l_LEAK
1
µA
V_OH
VDD5V-0.5
V
V_OL
GND+0.4
V
C_L
50
pF
4
mA
I_OUT
Note
V
0.3 * VDD5V
Table 4:DC/AC characteristics
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Output current
Max
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Low level output voltage
Typ
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AS5048A/AS5048B
Datasheet
Magnetic Rotary Encoder
14-bit Angular Position Sensor
VDD5V = 5V, TAmbient = -40 to +150°C unless noted otherwise
Symbol
Min
Typ
Max
Unit
Magnetic input field
Bz
30
50
70
mT
Output sampling rate
fsample
10.2
11.25
12.4
kHz
Output Resolution
RES
Sensor output noise
Noise
14
Bit
0.06
Deg
Note
2.73LSB@14bit, rms
value
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Parameter
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Electrical System Specifications
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2.4
System propagation delay
tprop
90.7
100
110.2
µs
PWM frequency
fPWM
0.907
1
1.102
kHz
±0.4
Deg
Assuming 8 mm
diameter of magnet
Deg
Assuming 8 mm
diameter of magnet and
500 um displacement in
x and y
Assuming 8 mm
diameter of magnet and
500 um displacement in
x and y
Non-linearity optimum placement of
magnet
INLOPT
Non-linearity @displacement of
magnet
INLDIS
Non-linearity @displacement of
magnet and temperature -40 -150
degC
Startup Time
±0.7
INLDIS+TEMP
±1.2
Deg
tstartup
10
ms
Table 5 System specification
Global Timing Conditions
Parameter
Symbol
Internal Master Clock
Min
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2.5
FOSC
Typ
Max
4.5
4.95
1/FOSC
Unit
MHz
Note
±10%
Hz
Table 6 Global timing conditions
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TOSC
4.05
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AS5048A/AS5048B
Datasheet
Magnetic Rotary Encoder
14-bit Angular Position Sensor
3
Functional Description
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The AS5048 is a magnetic Hall sensor system manufactured in a CMOS process. A lateral Hall sensor array is used to measure
the magnetic field components perpendicular to the surface of the chip. The AS5048 is uses self-calibration methods to
eliminate signal offset and sensitivity drifts.
The integrated Hall sensors are placed around the center of the device and deliver a voltage representation of the magnetic flux
Bz.
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Through Sigma-Delta Analog-to-Digital Converter (ADC) and Digital Signal-Processing (DSP) algorithms, the AS5048 provides
accurate high-resolution absolute angular position information. This is accomplished by a Coordinate Rotation Digital Computer
(CORDIC) calculates the angle and the magnitude of the Hall array signals.
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The DSP is also used to provide digital information at the outputs that indicate movements of the magnet towards or away from
the device’s surface, in the z-axis.
A small diametrically magnetized (two-pole) standard magnet provides the angular position information. Depending on the
system requirements different magnet diameters are possible. Additional flexibility is given by the wide range of the magnetic
input range. The AS5048 can be combined with NeFeB, SmCo and alternative magnet materials e.g. hard ferrites. The AS5048
provides a 14-bit binary code representing the angular position of the magnet. The type of output is pre-programmed as SPI
version A or I2C version B. Simultaneously a PWM output signal is available in 12 bit format.
A simple programming of the zero position is possible over the interface. No additional programmer is needed. The AS5048
uses one time programmable (OTP) fuses for permanent programming of the user settings. The verification is possible over a
simple digital readout of the OTP content.
4
4.1
Operation
Supply Voltage Configuration
The AS5048 operates at 5V ±10%, using an internal Low-Dropout (LDO) voltage regulator. In addition a 3.3V operation is
possible. The VDD3V output is intended for internal use only. It must not be loaded with an external load.
3.3V Operation
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5V Operation
10µF
VDD3V
VDD3V
100nF
10µF
100nF
LDO
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LDO
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VDD5V
VDD5V
Internal
VDD3.3V
Internal
VDD3.3V
4.5 - 5.5V
3.0 - 3.6V
GND
GND
Figure 2: Connections for 5V and 3.3V supply voltages
Note: The pin VDD3V must always be buffered by a 10 µF capacitor in 5V operation. It must not be left floating, as this may
cause unstable internal supply voltages which may lead to larger output jitter of the measured angle.
In 3V operation the VDD3V must be shorted to VDD5V. The ambient temperature Tamb is limited to 125 degC in this mode.
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AS5048A/AS5048B
Datasheet
Magnetic Rotary Encoder
14-bit Angular Position Sensor
SPI Interface
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4.2
4.2.1
SPI Interface Signals (4-Wire Mode, Wire_mode = 1)
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The 16 bit SPI Interface enables read / write access to the register blocks and is compatible to a standard micro controller
interface. The SPI is active as soon as CSn is pulled low. The AS5048A then reads the digital value on the MOSI(master out
slave in) input with every falling edge of CLK and writes on its MISO (master in slave out) output with the rising edge. After 16
clock cycles CSn has to be set back to a high status in order to reset some parts of the interface core.
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The AS5048A only supports slave operation mode. Therefore CLK for the communication as well as the CSn signal has to be
provided by the test equipment. The following picture shows a basic interconnection diagram with one master and an AS5048A
device and a principle schematic of the interface core.
Figure 3 SPI Connection AS5048A with uC
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Because the interface has to decode the sent command before it can react and provide data the response of the chip to a
specific command applied at a time T can be accessed in the next transmission cycle ending at T + TCOM.
The data are sent and read with MSB first. Every time the chip is accessed it is sending and receiving data.
Revision 1.3
Figure 4 SPI Command/Response Data Flow
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AS5048A/AS5048B
Datasheet
Magnetic Rotary Encoder
14-bit Angular Position Sensor
4.2.2
SPI Timing
CSn
(Input )
tL
tclk
tclkL
tclkH
tH
CLK
(Input )
tOZ
MISO
(Output )
data [15]
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tMISO
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tCSn
data [14]
data[0]
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tOZ
tMOSI
MOSI
(Input )
data[15]
data [14]
data [0]
Figure 5 SPI Timing Diagram
Parameter
tL
tL
Description
Min
Max
Unit
Time between CSn falling edge and CLK rising edge
10 (2)
ns
Time between CSn falling edge and CLK rising edge
350 (1)
ns
TCLK
Serial clock period
100
ns
tCLKL
Low period of serial clock
50
ns
tCLKH
High period of serial clock
tH
Time between last falling edge of CLK and rising edge of CSn
50
ns
tCLK / 2
ns
TCSnH
High time of CSn between two transmissions
10 (2)
ns
TCSnH
High time of CSn between two transmissions
350 (1)
ns
tMOSI
Data input valid to clock edge
tMISO
CLK edge to data output valid
20
20
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Table 7 SPI Timing Characteristics
Notes:
(1) Synchronization with the internal clock 2 * t CL K_ SYS + 10 ns (e.g. at 8 MHz 253 ns)
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(2) No synchronization needed because the internal clock is inactive
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ns
ns
AS5048A/AS5048B
Datasheet
Magnetic Rotary Encoder
14-bit Angular Position Sensor
4.2.3
SPI Connection to the Host UC
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Single Slave Mode
Figure 6 Single Slave Mode
3 Wire Mode (read only):
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Multiple Slave, n+3 Wire (Separate ChipSelect)
Revision 1.3
Figure 7 Multiple Slave, n+3 Wire (Separate ChipSelect)
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AS5048A/AS5048B
Datasheet
Magnetic Rotary Encoder
14-bit Angular Position Sensor
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Daisy Chain, 4 Wire
Figure 8 Daisy Chain, 4 Wire
4.2.4
SPI Communication Command Package
Every command sent to the AS5048A is represented with the following layout.
Command Package
MSB
14
PAR
RWn
13
12
11
10
9
8
7
6
5
4
3
2
1
Address<13:0>
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Bit
Bit Definition & Description
PAR
Parity bit (EVEN)
14 bit address code
Table 8 SPI Command Package
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Address
Indicates read(1) or write(0) command
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RWn
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LSB
AS5048A/AS5048B
Datasheet
Magnetic Rotary Encoder
14-bit Angular Position Sensor
4.2.5
Read Package (Value Read from AS5048A)
Read Package
Bit
MSB
14
PAR
EF
13
12
11
10
9
8
7
6
5
4
3
Data<13:0>
Parity bit (EVEN)
EF
Error flag indicating a transmission error in a previous host transmission
Data
14 bit addressed data
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PAR
2
1
LSB
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Bit Definition & Description
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The read frame always contains two alarm bits, the parity and error flags and the addressed data of the previous read
command.
Table 9 SPI read package
4.2.6
Write Data Package (Value Written to AS5048A)
The write frame is compatible to the read frame and contains two additional bits, parity flag and R flag.
If the previous command was a write command a second package has to be transmitted.
Data Package
Bit
MSB
14
PAR
R
13
12
11
10
9
8
7
6
5
4
3
2
1
Data <13:0>
Bit Definition & Description
PAR
Parity bit (EVEN)
R
Has to be 0
Data
14 bit data to write to former selected address
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Table 10 SPI write data package
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LSB
AS5048A/AS5048B
Datasheet
Magnetic Rotary Encoder
14-bit Angular Position Sensor
SPI NOP
x0001 Clear Error Flag
x0003
Programming
Control
OTP Register
x0016
Zero Position Hi
OTP Register
Zero Position
Low 6 LSBs
R
R
R/W
R/W
+
Program
R/W
+
Program
R
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Diagnostics +
x3FFD Automatic Gain
Control (AGC)
x3FFE
Magnitude
R
x3FFF
Angle
R
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Revision 1.3
Access
Type Bit Nr.
Symbol
13
:
0
13
:
3
2
1
0
13
:
7
6
5
4
3
2
1
0
Default
NOP
0
not used
n.a.
Parity Error
Command Invalid
Framing Error
0
Description
No operation dummy information
Error Register. All errors are cleared by access
13
:
8
7
:
0
13
:
6
5
:
0
13
12
11
10
9
8
7
:
0
13
:
0
13
:
0
not used
Verify
not used
0
Burn
Programming control register.
Programming must be enabled before burning the
fuse(s). After programming is a verification mandatory.
See programming procedure.
reserved
Programming Enable
not used
0
Zero Position <13>
:
Zero Position <6>
0
:
0
not used
0
Zero Position <5>
:
Zero Position <0>
0
:
0
not used
n.a.
Comp High
Comp Low
COF
OCF
AGC value<7>
:
AGC value<0>
Magnitude<13>
:
Magnitude<0>
Angle <13>
:
Angle<0>
0
0
0
1
1
:
0
0
:
0
0
:
0
Zero Position value high byte
ca
x0017
ch
Readout Registers
Programmable Customer settings
Control and Error Registers
x0000
Name
lv
Address
hex
al
id
Register Map SPI
am
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4.2.7
Zero Position remaining 6 lower LSB's
Diagnostics flags
Automatic Gain Control value.
0 decimal represents high magnetic field
255 decimal represents low magnetic field
Magnitude information after ATAN calculation
Angle information after ATAN calculation
and zero position adder
Table 11 SPI register map
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Page 15 of 29
AS5048A/AS5048B
Datasheet
Magnetic Rotary Encoder
14-bit Angular Position Sensor
4.2.8
SPI Interface Commands
al
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READ Command
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lv
For a single READ command two transmission sequences are necessary. The first package written to the AS5048 contains the
READ command (MSB-1 high) and the address the chip has to access, the second package transmitted to the AS5048 device
can be any command the chip has to process next. The content of the desired register is available in the MISO register of the
master device at the end of the second transmission cycle.
Figure 9 READ Command
WRITE Command
Te
ch
ni
ca
A single WRITE command takes two transmission cycles. With a NOP command after the WRITE command you can verify the
sent data with three transmission cycles because the data will be send back during the following command.
Revision 1.3
Figure 10 WRITE Command
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Page 16 of 29
AS5048A/AS5048B
Datasheet
Magnetic Rotary Encoder
14-bit Angular Position Sensor
al
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CLEAR ERROR FLAG Command
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The CLEAR ERROR FLAG command is implemented as READ command. This command clears the ERROR FLAG which is
contained in every READ frame. Before the ERROR FLAG is cleared the error register content comes back with the information
which error type was occurred. On the next new READ register the ERROR FLAG is cleared
Figure 11 CLEAR ERROR FLAG Command
The package necessary to perform a CLEAR ERROR FLAG is built up as follows.
MSB
14
PAR
1
13
12
11
10
9
8
7
6
5
4
3
2
1
LSB
0
0
0
0
0
0
0
0
0
0
0
0
0
1
ni
Bit
ca
CLEAR ERROR FLAG Command
Table 12 Clear Error Flag Command
ch
Possible conditions which force the ERROR FLAG to be set:
wrong parity
wrong number of clocks (no full transmission cycle or too many clocks)
Te
Note: If the error flag is set to high because of a communication problem the flag remains set until it will be cleared by the
CLERAR ERROR FLAG command.
Revision 1.3
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AS5048A/AS5048B
Datasheet
Magnetic Rotary Encoder
14-bit Angular Position Sensor
NOP Command
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The NOP command represents a dummy write to the AS5048.
Figure 12 NOP Command
The NOP command frame looks like follows.
NOP Command
Bit
MSB
14
13
12
11
10
9
8
7
6
5
4
3
2
1
LSB
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
ca
Table 13 NOP Command
Te
ch
ni
The chip’s response on this command is 0x0000 – if no error happens.
Revision 1.3
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AS5048A/AS5048B
Datasheet
Magnetic Rotary Encoder
14-bit Angular Position Sensor
4.3
I²C interface
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The AS5048B supports 2-wire high-speed I²C protocol in device mode. The host MCU (master) has to initiate the data
transfers. The 7-bit device address of the slave depends on the state of the OTP I2C register 21 (0x15) bit 0…4 + 2 I2C
address selection pin 3 and 4.
Random/Sequential Read
Byte/Page Write
Standard : 0 to 100kHz clock frequency (slave mode)
Fast Mode : 0 to 400kHz clock frequency (slave mode)
High Speed: 0 to 3.4MHz clock frequency (slave mode)
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Supported modes:
The SDA signal is bidirectional and is used to read and write the serial data. The SCL signal is the clock generated by the
host MCU, to synchronize the SDA data in read and write mode. The maximum I²C clock frequency is 3.4MHz, data are
triggered on the rising edge of SCL.
4.3.1
I²C Electrical Specification
HS-mode CB=100pF
FS-mode+
Symbol
Parameter
Condition
HS-mode CB=400pF
Min
Max
Min
Max
Min
Max
Unit
VIL
LOW-Level Input Voltage
-0.5
0.3VDD
-0.5
0.3VDD
-0.5
0.3VDD
V
VIH
HIGH-Level Input Voltage
0.7VDD
VDD + 0.5
(1)
0.7VDD
VDD +
0.7VDD
VDD + 0.5
(1)
V
0.5 (1)
Hysteresis of Schmitt Trigger
Inputs
VDD< 2V
0.1VDD
--
0.1VDD
--
0.1VDD
--
V
VOL
LOW-Level Output Voltage
(open-drain or open-collector)
at 3mA Sink Current
VDD < 2V
--
0.2VDD
--
0.2VDD
--
0.2VDD
V
IOL
LOW-Level Output Current
--
--
--
--
mA
ICS
Pull-up current of SCLH
current source
tSP
Pulse Width of Spikes that
must be suppressed by the
Input Filter
ca
Vhys
20
ch
ni
VOL = 0.4V
Input Current at each I/O Pin
CB
Total Capacitive Load for
each Bus Line
Te
Ii
CI/O
I/O Capacitance (SDA, SCL)
Input Voltage
between
--
--
3
12
3
12
mA
--
50 (2)
--
10
--
10
ns
-10
+10 (3)
--
10
--
10
µA
--
550
--
100
--
400
pF
--
10
--
10
--
10
pF
Table 14 I²C Electical Specification
(1) Maximum V IH = V DDmax +0.5V or 5.5V
(2) Input filters on the SDA and SCL inputs suppress noise spikes of less than 50 ns.
(3) I/O pins of Fast-mode and Fast-mode Plus devices must not obstruct the SDA and SCL lines if VDD is switched
off.
Revision 1.3
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Page 19 of 29
AS5048A/AS5048B
Datasheet
Magnetic Rotary Encoder
14-bit Angular Position Sensor
I²C Timing
FS-mode+
Symbol
Parameter
Condition
HS-mode CB=100pF
HS-mode CB=400pF
(5)
al
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4.3.2
Min
Max
Min
Max
Min
Max
Unit
--
1000
--
3400
--
1700
kHz
500
--
ns
SCL clock Frequency
tBUF
Bus Free Time; time between
STOP and START Condition
500
--
500
--
tHD;STA
Hold Time; (Repeated) START
Condition (1)
260
--
160
--
tLOW
LOW Period of SCL Clock
500
--
160
--
tHIGH
HIGH Period of SCL Clock
260
--
60
tSU;STA
Setup Time for a Repeated
START condition
260
--
tHD;DAT
Data Hold Time (2)
0
tSU;DAT
Data Setup Time (3)
tR
Rise Time of SDA and SCL
Signals
50
20+0.1
Cb
tF
Fall time of SDA and SCL signals
trCL
Rise time of SCLH signal
trCL1
160
ns
320
--
ns
--
120
--
ns
160
--
160
--
ns
450
0
70
0
150
ns
--
10
--
10
--
ns
120
--
--
--
--
ns
20+0.1
Cb
120 (4)
--
--
--
--
ns
Ext. pull-up
source of 3mA
--
--
10
40
20
80
ns
Rise time of SCLH signal after
repeated START condition and
after an acknowledge bit
Ext. pull-up
source of 3mA
--
--
10
80
20
160
ns
tfCL
Output rise time of SCLH signal
Ext. pull-up
source of 3mA
--
--
10
40
20
80
ns
trDA
Output rise time of SDAH signal
--
--
10
80
20
160
ns
tfDA
Output rise time of SDAH signal
--
--
10
80
20
160
ns
tSU;STO
260
--
160
--
160
--
ns
Noise margin at LOW level
0.1VDDp
--
0.1VDDp
--
0.1VDDp
--
V
Noise margin at HIGH level
0.2VDDp
--
0.2VDDp
--
0.2VDDp
--
V
ca
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--
ni
lv
fSCLK
Setup Time for STOP Condition
VnL
ch
VnH
after this time the first clock is generated
A device must internally provide a minimum hold time (120ns / max 250ns for Fast-mode Plus, 80ns / max 150ns for Highspeed mode) for the SDA signal (referred to the V I Hm in of the SCL) to bridge the undefined region of the falling edge of SCL.
A fast-mode device can be used in standard-mode system, but the requirement t SU; D AT = 250ns must then e met. This is
automatically the case if the device does not stretch the LOW period of the SCL signal. If such a device does strech the LOW
period of the SCL signal, it must output the next data bit to the SDA line t Rm ax + T SU; DAT = 1000 + 250 = 1250ns before the SCL
line is released.
In Fast-mode Plus, fall time is specified the same for both output stage and bus timing. If series resistors are used this has to
be considered for bus timing
For capacitive bus loads between 100pF and 400pF, the timing parameters must be linearly interpolated
Te
(1)
(2)
Table 15 I²C Timing
(3)
(4)
(5)
Revision 1.3
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AS5048A/AS5048B
Datasheet
Magnetic Rotary Encoder
14-bit Angular Position Sensor
4.3.3
Register Table
Programmable Customer settings
21
R/W
I²C slave
address
R/W
+
Program
22
OTP Register
Zero Position
Hi
R/W
+
Program
23
OTP Register
Zero Position
Low 6 LSBs
R/W
+
Program
250
Automatic
Gain
Control
R
252
Diagnostics
R
R
Magnitude
R
ni
253
R
ch
254
Angle
Te
255
Revision 1.3
Symbol
7
6
5
4
3
2
1
0
7
:
5
Default
Description
not used
Verify
not used
Burn
0
reserved
Programming Enable
not used
n.a.
4
I²C address<4>
:
0
7
:
0
7
6
5
:
0
7
:
0
7
:
4
3
2
1
0
7
:
0
7
6
5
:
0
7
:
0
7
6
5
:
0
:
I²C address<0>
Zero Position <13>
:
Zero Position <6>
internally
inverted
:
0
0
:
0
ca
251
Readout Registers
Programming
Control
Access
Type Bit Nr.
Programming control register.
Programming must be enabled before burning the
fuse(s). After programming is an verification mandatory.
See programming procedure.
lv
3
Name
am
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nt
st
il
Control OTP
Address
dec
al
id
The following registers / functions are accessible over the serial I²C interface.
R
not used
n.a.
Zero Position <5>
:
Zero Position <0>
AGC value<7>
:
AGC value<0>
0
:
0
1
:
0
not used
n.a.
Comp High
Comp Low
COF
OCF
Magnitude<13>
:
Magnitude<6>
0
0
0
1
0
:
0
not used
Magnitude<5>
:
Magnitude<0>
Angle<13>
:
Angle<6>
n.a.
0
:
0
0
:
0
not used
n.a.
Angle<5>
:
Angle<0>
0
:
0
Table 16 Register Map I2C
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Page 21 of 29
I²C slave address
slave address consist of 5 programable bits (MSBs)
and the hardware setting of Pins A1 and A2
I²C address <4> is by default not programmed and due
to the inversion defined as '1'
Zero Position value high byte
Zero Position remaining 6 lower LSB's
Automatic Gain Control value.
0 decimal represents high magnetic field
255 decimal represents low magnetic field
Diagnostic flags
Magnitude information afer ATAN calculation
Angle Value afer ATAN calculation
and zero position adder
AS5048A/AS5048B
Datasheet
Magnetic Rotary Encoder
14-bit Angular Position Sensor
X X X X X X X X
ACK
R/W
ACK
X X X X X X X X
Register Address
Data Byte (n)
al
id
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st
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LSB
Slave Address
ACK
Stop
A A
1 0 0 0 0
2 1
Start
Data Byte (n)
HW
Pins
OTP cotent
(Default)
random write
X X X X X X X X
LSB
Slave Address
LSB
Register Address
R/W
ACK
X X X X X X X X
ACK
Start
Start
Slave Address
A A
1 0 0 0 0
2 1
lv
HW
Pins
A A
1 0 0 0 0
2 1
Stop
HW
Pins
OTP cotent
(Default)
random read
ACK
I²C Slave address
R/W
ACK
4.3.4
Figure 13 Slave address construction
The slave address consists of the hardware setting on pins A1, A2 and upper MSBs programmable by the user. The MSB of
the slave address (yellow) is internally inverted. This means that by default the resulting data is ‘1’. A read of the I²C slave
address register 21 will return a ‘0’ at the MSB.
4.4
PWM interface
The AS5048 provides a pulse width modulated output (PWM), whose duty cycle is proportional to the measured angle. The
PWM frequency is internally trimmed to an accuracy of ± 10% over full temperature range. This tolerance can be cancelled
by measuring the complete duty cycle.
The PWM signal consists of different sections:
•
-> PWM = ‘not(system_error)’
Data:
4095 clocks -> PWM = ‘angle_zero’ / ‘low’ (in case of error)
Exit:
8 clocks
ch
•
Error_n:
4 clocks
-> PWM = ‘high’
ca
•
Init:
12 clocks
ni
•
-> PWM = ‘low’
Te
In case of an error the data section is set to zero.
Revision 1.3
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AS5048A/AS5048B
Datasheet
Figure 14 PWM Format
Symbol
Value
Unit
T_PWM
4119
T_PWM_BIT
PWM – Bit Time
T_PWM_BIT
1
T_OSC
PWM Resolution
N_PWM
4096
bit
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Parameter
PWM – Period
Table 17 PWM Period and resolution
5
lv
al
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Magnetic Rotary Encoder
14-bit Angular Position Sensor
Package Drawings and Markings
ch
ni
ca
Package type: TSSOP14
Figure 15 Package Marking
Te
5.1.1
Assembly Lot Code
The assembly lot code for standard “ YYWWIZZ ” is composed as follows:
X
-
Interface type: A=SPI / B=I 2 C
YY
-
Year
WW
-
Week
I
-
Plant identification letter
ZZ
-
Letters for free traceability
Revision 1.3
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AS5048A/AS5048B
Datasheet
Magnetic Rotary Encoder
14-bit Angular Position Sensor
Te
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14-Lead Thin Shrink Small Outline Package TSSOP-14
Revision 1.3
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Page 24 of 29
AS5048A/AS5048B
Datasheet
Magnetic Rotary Encoder
14-bit Angular Position Sensor
Application Information
6.1
Programming of the AS5048
6.1.1
Programming of the zero position
al
id
6
lv
The absolute angle position can be permanent programmed over the interface. This could be useful for random placement of
the magnet on the rotation axis. A readout at the mechanical zero position can be performed and written back into the IC.
With permanent programming the position is non-reversible stored in the IC. This programming can be performed only once.
6.1.2
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To simplify the calculation of the zero position it is only needed to write the value in the IC which was read out before from
the angle register.
Programming sequence with verification
To program the zero position is needed to perform following sequence:
1.
2.
3.
4.
5.
6.
7.
8.
Read angle information
Set the Programming Enable bit in the OTP control register
Write previous read angle position into OTP zero position register
Read back for verification the zero position register data
Set the Burn bit to start the automatic programming procedure
Read angle information (equals to 0)
Set the Verify bit to load the OTP data again into the internal registers with modified threshold comparator levels
Read angle information (equals to 0)
The programming can either be performed in 5V operation using the internal LDO, or in 3V operation but using a minimum
supply voltage of 3.3V. In case of 3V operation, also a 10uF capacitor is required on the VDD3 pin.
6.2
Diagnostic functions of the AS5048
The AS5048 provides diagnostics functions of the IC and also diagnostic functions of the magnetic input field
ca
Following diagnostic flags are available:
See Table 11 register address x3FFD (AS5048A) or Table 16 register address 251 dec (AS5048B)
ni
OCF ( O ffset C ompensation F inished), logic high indicates the finished Offset Compensation Algorithm. After power up the
flag remains always to logic high.
ch
COF ( C ordic O ver f low), logic high indicates an out of range error in the CORDIC part. When this bit is set, the angle and
magnitude data is invalid. The absolute output maintains the last valid angular value.
Te
COMP low , indicates a weak magnetic field. It is recommended to monitor in addition the magnitude value.
COMP high , indicated a high magnetic field. It is recommended to monitor the magnitude value.
Revision 1.3
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AS5048A/AS5048B
Datasheet
Magnetic Rotary Encoder
14-bit Angular Position Sensor
6.3
Choosing the Proper Magnet
al
id
The AS5048 works with a variety of different magnets in size and shape. A typical magnet could be 6-8 mm in diameter and
≥2.5mm in height The magnetic field strength perpendicular to the die surface has to be in the range of ±30mT…±70mT
(peak).
am
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ty p. 6-8mm diameter
lv
The magnet’s field strength should be verified using a gauss-meter. The magnetic flux B Z at a given distance, along a
concentric circle with a radius of 1.1mm (R1), should be in the range of ±30mT…±70mT.
N
S
Magnet axis
R1
Magnet axis
Vertical field
component
N
S
R1 concentric circle;
radius 1.1mm
Vertical field
component
(30…70mT)
0
Figure 16: Typical magnet and magnetic flux distribution
Te
Revision 1.3
360
3 60
ch
ni
ca
Bv
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Page 26 of 29
AS5048A/AS5048B
Datasheet
Magnetic Rotary Encoder
14-bit Angular Position Sensor
6.4
Physical Placement of the Magnet
3.2 mm
1
2.5 mm
Defined
center
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Rd
lv
3.2 mm
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The best linearity can be achieved by placing the center of the magnet exactly over the defined center of the chip as shown
in the drawing below:
2.5 mm
Area of recommended maximum
magnet misalignment
Figure 17: Defined chip center and magnet displacement radius
6.5
Magnet Placement
The magnet’s center axis should be aligned within a displacement radius R d of 0.25 mm (larger magnets allow more
displacement e.g. 0.5 mm) from the defined center of the IC.
The magnet may be placed below or above the device. The distance should be chosen such that the magnetic field on the
die surface is within the specified limits The typical distance “z” between the magnet and the package surface is 0.5mm to
2.5mm, provided the use of the recommended magnet material and dimensions (6mm x 3mm). Larger distances are
possible, as long as the required magnetic field strength stays within the defined limits.
N
Package surface
0.2299±0.100
0.2341±0.100
Te
S
Die surface
0.7701±0.150
ch
ni
ca
However, a magnetic field outside the specified range may still produce usable results, but the out-of-range condition will be
indicated by indication flags.
Figure 18: Vertical placement of the magnet
Revision 1.3
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Page 27 of 29
AS5048A/AS5048B
Datasheet
Magnetic Rotary Encoder
14-bit Angular Position Sensor
al
id
Ordering Information
Package
14 –Bit Programmable Magnetic Rotary Encoder
with SPI-Interface
Tape&Reel
TSSOP 14
14 –Bit Programmable Magnetic Rotary Encoder
with I2C-Interface
Tape&Reel
Description
AS5048A-HTSP
AS5048B-HTSP
lv
Delivery
Form
Model
TSSOP 14
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7
Table 18: Ordering Information
8
Revision History
Revision
Date
Owner
mub
Description
1.0
10-April-2012
Initial revision
1.1
16-April-2012
mub
Minor correction text
1.2
09-May-2012
mub
Default pin configuration added. Minor text corrections
1.3
20-June-2012
mub
I2C Slave address explanation. Minor corrections.
Te
ch
ni
ca
www.austriamicrosystems.com
Revision 1.3
www.austriamicrosystems.com/AS5048
Page 28 of 29
AS5048A/AS5048B
Datasheet
Magnetic Rotary Encoder
14-bit Angular Position Sensor
9
Copyrights
Trademarks Registered ®. All rights reserved. The material herein may not be reproduced, adapted, merged,
translated, stored, or used without the prior written consent of the copyright owner.
al
id
Copyright © 1997-2012, austriamicrosystems AG, Schloss Premstaetten, 8141 Unterpremstaetten, Austria-Europe.
All products and companies mentioned are trademarks or registered trademarks of their respective companies.
lv
This product is protected by U.S. Patent No. 7,095,228.
10 Disclaimer
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Devices sold by austriamicrosystems AG are covered by the warranty and patent indemnification provisions appearing in its
Term of Sale. austriamicrosystems AG makes no warranty, express, statutory, implied, or by description regarding the
information set forth herein or regarding the freedom of the described devices from patent infringement.
austriamicrosystems AG reserves the right to change specifications and prices at any time and without notice. Therefore,
prior to designing this product into a system, it is necessary to check with austriamicrosystems AG for current information.
This product is intended for use in normal commercial applications. Applications requiring extended temperature range,
unusual environmental requirements, or high reliability applications, such as military, medical life-support or lifesustaining
equipment are specifically not recommended without additional processing by austriamicrosystems AG for each application.
Te
ch
ni
ca
The information furnished here by austriamicrosystems AG is believed to be correct and accurate. However,
austriamicrosystems AG shall not be liable to recipient or any third party for any damages, including but not limited to
personal injury, property damage, loss of profits, loss of use, interruption of business or indirect, special, incidental or
consequential damages, of any kind, in connection with or arising out of the furnishing, performance or use of the technical
data herein. No obligation or liability to recipient or any third party shall arise or flow out of austriamicrosystems AG
rendering of technical or other services.
Revision 1.3
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