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AS5245
Programmable 360º Magnetic Angle Encoder with Absolute SSI and
PWM Output
www.austriamicrosystems.com/AS5245 Revision 1.5 1 - 31
Data Sheet
1 General Description
The AS5245 is a contactless magnetic angle encoder for accurate
measurement up to 360º and includes two AS5145 devices in a
punched stacked leadframe.
It is a system-on-chip, combining integrated Hall elements, analog
front end and digital signal processing in a single device.
To measure the angle, only a simple two-pole magnet, rotating over
the center of the chip is required. The magnet may be placed above
or below the IC.
The absolute angle measurement provides instant indication of the
magnet’s angular position with a resolution of 0.0879º = 4096
positions per revolution. This digital data is available as a serial bit
stream and as a PWM signal.
An internal voltage regulator allows operation of the AS5245 from
3.3V or 5.0V supplies.
The AS5245 is fully automotive qualified to AEC-Q100, grade 0.
2 Key Features
Contactless high resolution rotational position encoding over a
full turn of 360º
Two digital 12-bit absolute outputs
Quadrature A/B (10- or 12-bit) and Index output signal
User programmable zero position
Failure detection mode for magnet placement monitoring and
loss of power supply
“Red-Yellow-Green” indicators display placement of magnet in
Z-axis
Tolerant to magnet misalignment and air gap variations
Wide temperature range: - 40ºC to +150ºC
Unique Chip Identifier
Fully automotive qualified to AEC-Q100, grade 0
Small package: QFN 32 LD (7x7)
3 Applications
The AS5245 is ideal for applications with an angular travel range
from a few degrees up to a full turn of 360º. The device is suitable for
Automotive applications like Throttle position sensors, Gas/brake
pedal position sensing, Headlight position control, Contactless rotary
position sensing, Front panel rotary switches and Replacement of
potentiometer.
DSP
Hall Array
&
Frontend
Amplifier
Absolute
Interface
(SSI)
Incremental
Interface
Sin
Cos
Ang
Mag
MagINCn
MagDECn
DO
PWM
CLK
DTEST1_A
DTEST2_B
Mode_Index
PDIO
CSn
PWM
Interface
OTP
Register
VDD5V
VDD3V3
LDO 3.3V
Mux AS5245
Note: This Block Diagram presents only one die
Figure 1. AS5245 Block Diagram
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AS5245
Data Sheet - Contents
Contents
1 General Description .................................................................................................................................................................. 1
2 Key Features............................................................................................................................................................................. 1
3 Applications............................................................................................................................................................................... 1
4 Pin Assignments ....................................................................................................................................................................... 3
4.1 Pin Descriptions.................................................................................................................................................................................... 4
5 Absolute Maximum Ratings ...................................................................................................................................................... 5
6 Electrical Characteristics........................................................................................................................................................... 6
6.1 System Specifications .......................................................................................................................................................................... 7
7 Timing Characteristics .............................................................................................................................................................. 9
8 Detailed Description................................................................................................................................................................ 10
8.1 Mode_Index Pin.................................................................................................................................................................................. 10
8.2 Synchronous Serial Interface (SSI) .................................................................................................................................................... 11
8.2.1 Serial Data Contents.................................................................................................................................................................. 11
8.2.2 Z-axis Range Indication (Push Button Feature, Red/Yellow/Green Indicator)........................................................................... 12
8.2.3 Incremental Mode ...................................................................................................................................................................... 12
8.2.4 Sync Mode................................................................................................................................................................................. 14
8.2.5 Sine/Cosine Mode ..................................................................................................................................................................... 14
8.2.6 Daisy Chain Mode ..................................................................................................................................................................... 14
8.3 Pulse Width Modulation (PWM) Output.............................................................................................................................................. 15
8.3.1 Changing the PWM Frequency.................................................................................................................................................. 16
8.4 Analog Output..................................................................................................................................................................................... 16
9 Application Information ........................................................................................................................................................... 17
9.1 Programming the AS5245 .................................................................................................................................................................. 17
9.1.1 Zero Position Programming ....................................................................................................................................................... 17
9.1.2 OTP Memory Assignment.......................................................................................................................................................... 18
9.1.3 User Selectable Settings ........................................................................................................................................................... 18
9.1.4 OTP Default Setting................................................................................................................................................................... 19
9.1.5 Redundancy............................................................................................................................................................................... 19
9.1.6 Redundant Programming Option............................................................................................................................................... 19
9.2 Alignment Mode.................................................................................................................................................................................. 20
9.3 3.3V / 5V Operation............................................................................................................................................................................ 21
9.4 Choosing the Proper Magnet.............................................................................................................................................................. 22
9.5 Failure Diagnostics............................................................................................................................................................................. 23
9.5.1 Magnetic Field Strength Diagnosis ............................................................................................................................................ 23
9.5.2 Power Supply Failure Detection ................................................................................................................................................ 23
9.6 Angular Output Tolerances................................................................................................................................................................. 23
9.6.1 Accuracy.................................................................................................................................................................................... 23
9.6.2 Transition Noise......................................................................................................................................................................... 25
9.6.3 High Speed Operation ............................................................................................................................................................... 25
9.6.4 Propagation Delays ................................................................................................................................................................... 26
9.6.5 Internal Timing Tolerance .......................................................................................................................................................... 26
9.6.6 Temperature .............................................................................................................................................................................. 26
9.6.7 Accuracy over Temperature ...................................................................................................................................................... 26
9.7 AS5245 Differences to AS5045.......................................................................................................................................................... 27
10 Package Drawings and Markings ......................................................................................................................................... 28
11 Ordering Information ............................................................................................................................................................. 30
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AS5245
Data Sheet - Pin Assignments
4 Pin Assignments
Figure 2. Pin Assignments (Top Vie w)
AS5245
252627282930
161514131211
24
23
22
21
20
19
1
2
3
4
5
6
7
8
18
17
3132
109
VSS_Bottom
PDIO_Top
PDIO_Bottom
CLK_Top
CLK_Bottom
DO_Top
DO_Bottom
CSn_Bottom
VDD3V_Bottom
NC
NC
NC
NC
PWM_Top
PWM_Bottom
CSn_Top
DTest1_A_Top
MagDECn_Bottom
MagDECn_Top
MagINCn_Bottom
MagINCn_Top
VDDA5V_Top
VDDA5V_Bottom
VDD3V_Top
DTest1_A_Bottom
DTest2_B_Top
DTest2_B_Bottom
NC
NC
Mode_Index_Top
Mode_Index_Bottom
VSS_Top
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AS5245
Data Sheet - Pin Assignments
4.1 Pin Descriptions
Table 1. Pin Descriptions
Pin Name Pin Number Pin Type Description
DTest1_A 1, 32 Digital output Test output in default mode
DTest2_B 2, 3 Digital output Test output in default mode
NC 4, 5 - For internal use. Must be left unconnected
Mode_Index 6, 7 Digital I/O pull-down Select between slow (open, low: VSS) and fast (high) mode. Internal pull-
down resistor. Hard wired connection to VDD or GND recommended.
VSS 8, 9 Supply pin Negative Supply Voltage (GND)
PDIO 10, 11 Digital input pull-down
OTP Programming Input and Data Input for Daisy Chain mode.
Internal pull-down resistor (74kΩ). Should be connected to VSS if
programming is not used.
CLK 12, 13 Digital input, Schmitt-
trigger input Clock Input of Synchronous Serial Interface; Schmitt-Trigger input
DO 14, 15 Digital output / tri-
state Data Output of Synchronous Serial Interface
CSn 16, 17 Digital input pull-up,
Schmitt-trigger input
Chip Select. Active low. Schmitt-Trigger input, internal pull-up resistor
(50kΩ)
PWM 18, 19 Digital output Pulse Width Modulation
NC 20, 21 - For internal use. Must be left unconnected
NC 22, 23 - For internal use. Must be left unconnected
VDD3V3 24, 25 Supply pin 3V-Regulator Output for internal core, regulated from VDD5V. Connect to
VDD5V for 3V supply voltage. Do not load externally.
VDD5V 26, 27 Supply pin Positive Supply Voltage, 3.0V to 5.5V
MagINCn 28, 29 Digital output open
drain
Magnet Field Magnitude Increase. Active low. Indicates a distance
reduction between the magnet and the device surface.
MagDECn 30, 31 Digital output open
drain
Magnet Field Magnitude Decrease. Active low. Indicates a distance
increase between the device and the magnet.
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AS5245
Data Sheet - Absolute Maximum Ratings
5 Absolute Maximum Ratings
Stresses beyond those listed in Table 2 may cause permanent damage to the device. These are stress ratings only, and functional operation of
the device at these or any other conditions beyond those indicated in Electrical Characteristics on page 6 is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect device reliability.
Table 2. Absolute Maximum Ratings
Parameter Min Max Units Comments
DC supply voltage at pin VDD5V -0.3 7 V
DC supply voltage at pin VDD3V3 -0.3 5 V
Input pin voltage -0.3 7 V Pins Prog, MagINCn, MagDECn, CLK, CSn
Input current (latchup immunity) -100 100 mA Norm: EIA/JESD78 Class II Level A
Electrostatic discharge ±2 kV Norm: JESD22-A114E
Storage temperature -55 +150 ºC
Body temperature (Lead-free package) 260 ºC t=20 to 40s, Norm: IPC/JEDEC J-Std-020C
Lead finish 100% Sn “matte tin”
Humidity non-condensing 5 85 %
Ambient temperature -40 150 ºC
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AS5245
Data Sheet - Electrical Characteristics
6 Electrical Characteristics
TAMB = -40 to +150ºC, VDD5V = 3.0-3.6V (3V operation) VDD5V = 4.5-5.5V (5V operation) unless otherwise noted.
Table 3. Electrical Characteristics
Symbol Parameter Condition Min Typ Max Unit
Operating Conditions
TAMB Ambient temperature -40 +150 ºC
Isupp Supply current (one die only) 16 21 mA
VDD5V Supply voltage at pin VDD5V
5V Operation
4.5 5.0 5.5
V
VDD3V3 Voltage regulator output voltage at pin
VDD3V3 3.0 3.3 3.6
VDD5V Supply voltage at pin VDD5V 3.3V Operation
(pin VDD5V and VDD3V3 connected)
3.0 3.3 3.6 V
VDD3V3 Supply voltage at pin VDD3V3 3.0 3.3 3.6
VON Power-on reset thresholds
On voltage; 300mV typ. hysteresis
DC supply voltage 3.3V (VDD3V3)
1.37 2.2 2.9
V
VOFF Power-on reset thresholds
Off voltage; 300mV typ. hysteresis 1.08 1.9 2.6
Programming Conditions
VPROG Programming voltage Voltage applied during programming 3.3 3.6 V
VProgOff Programming voltage off level Line must be discharged to this level 0 1 V
IPROG Programming current Current during programming 100 mA
Rprogrammed Programmed fuse resistance (log 1) 10µA maximum current@100mV 100k ∞Ω
Runprogrammed Unprogrammed fuse resistance (log
0) 2mA maximum current@100mV 50 100 Ω
DC Characteristics CMOS Schmitt-Tr igger Inputs: CLK, CSn (CSn = Internal Pull-up)
VIH High level input voltage Normal operation 0.7 *
VDD5V V
VIL Low level input voltage 0.3 *
VDD5V V
VIon- VIoff Schmitt Trigger hysteresis 1 V
ILEAK Input leakage current CLK only -1 1 µA
IiL Pull-up low level input current CSn only, VDD5V: 5.0V -30 -100
DC Characteristics CMOS / Program Input: PDIO
VIH High level input voltage 0.7 *
VDD5V VDD5V V
VPROG High level input voltage During programming,
Either with 3.3V or 5V supply 3.3 3.6 V
VIL Low level input voltage 0.3 *
VDD5V V
IiL High level input current VDD5V: 5.5V 30 100 µA
DC Characteristics CMOS Output Open Drain: MagINCn, MagDECn
IOZ Open drain leakage current 1 µA
VOL Low level output voltage VSS
+0.4 V
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AS5245
Data Sheet - Electrical Characteristics
6.1 System Specifications
TAMB = -40 to +150ºC, VDD5V = 3.0 to 3.6V (3V operation) VDD5V = 4.5 to 5.5V (5V operation) unless otherwise noted.
IOOutput current VDD5V: 4.5V 4 mA
VDD5V: 3V 2
DC Characteristics CMOS Output: PWM
VOH High level output voltage VDD5V–
0.5 V
VOL Low level output voltage VSS
+0.4 V
IOOutput current VDD5V: 4.5V 4 mA
VDD5V: 3V 2
DC Characteristi cs CMO S Output: A, B, Index
VOH High level output voltage VDD5V–
0.5 V
VOL Low level output voltage VSS
+0.4 V
IOOutput current VDD5V: 4.5V 4 mA
VDD5V: 3V 2
DC Characteristics Tri-state CMOS Output: DO
VOH High level output voltage VDD5V–
0.5 V
VOL Low level output voltage VSS
+0.4 V
IOOutput current VDD5V: 4.5V 4 mA
VDD5V: 3V 2
IOZ Tri-state leakage current 1 µA
Table 4. Input Specification
Symbol Parameter Condition Min Typ Max Unit
RES Resolution 0.088 deg 12 bit
INLopt Integral non-linearity (optimum)
Maximum error with respect to the best line fit.
Centered magnet without calibration, TAMB
=25ºC.
±0.5 deg
INLtemp Integral non-linearity (optimum)
Maximum error with respect to the best line fit.
Centered magnet without calibration,
TAMB = -40 to +150ºC
±0.9 deg
INL Integral non-linearity
Best line fit = (Errmax – Errmin) / 2
Over displacement tolerance with 6mm
diameter magnet, without calibration,
TAMB = -40 to +150ºC
±1.4 deg
DNL Differential non-linearity 12bit, no missing codes ±0.044 deg
TN Transition noise
1 sigma, fast mode (MODE = 1) 0.06
Deg
RMS
1 sigma, slow mode
(MODE = 0 or open) 0.03
Table 3. Electrical Characteristics
Symbol Parameter Condition Min Typ Max Unit
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AS5245
Data Sheet - Electrical Characteristics
Figure 3. Integral and Differential Non-Linearity Example
Integral Non-Linearity (INL) is the maximum deviation between actual position and indicated position.
Differential Non-Linearity (DNL) is the maximum deviation of the step length from one position to the next.
Transition Noise (TN) is the repeatability of an indicated position.
tPwrUp Power-up time
Fast mode (Mode = 1);
Until status bit OCF = 1 20
ms
Slow mode (Mode = 0 or open);
Until OCF = 1 80
tdelay
System propagation delay
absolute output : delay of ADC, DSP
and absolute interface
Fast mode (MODE = 1) 96
µs
Slow mode (MODE = 0 or open) 384
fSInternal sampling rate for absolute
output:
TAMB = 25ºC, slow mode
(MODE=0 or open) 2.48 2.61 2.74
kHz
TAMB = -40 to +150ºC, slow mode (MODE=0
or open) 2.35 2.61 2.87
fSInternal sampling rate for absolute
output
TAMB = 25ºC, fast mode
(MODE = 1) 9.90 10.42 10.94
kHz
TAMB = -40 to +150ºC, fast mode
(MODE=1) 9.38 10.42 11.46
CLK/SEL Read-out frequency Maximum clock frequency to read out serial
data 1MHz
Table 4. Input Specification
Symbol Parameter Condition Min Typ Max Unit
180° 360
°
0
°
0
512
1023
α
α
10bit code
0
1
2
0.35°
INL
Ideal curve
Actual curve
TN
512
1023
DNL+1LSB
[degrees]
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AS5245
Data Sheet - Timing Characteristics
7 Ti ming Characteristics
TAMB= -40 to +150ºC, VDD5V= 3.0 to 3.6V (3V operation) VDD5V= 4.5 to 5.5V (5V operation), unless otherwise noted.
Table 5. Timing Characteristics
Symbol Parameter Conditions Min Typ Max Units
Synchronous Serial Interface (SSI)
tDOactive Data output activated (logic high) Time between falling edge of CSn and
data output activated 100 ns
tCLKFE First data shifted to output register Time between falling edge of CSn and
first falling edge of CLK 500 ns
TCLK/2 Start of data output Rising edge of CLK shifts out one bit at a
time 500 ns
tDOvalid Data output valid Time between rising edge of CLK and
data output valid 413 ns
tDOtristate Data output tri-state After the last bit DO changes back to “tri-
state” 100 ns
tCSn Pulse width of CSn CSn =high; To initiate read-out of next
angular position 500 ns
fCLK Read-out frequency Clock frequency to read out serial data >0 1 MHz
Pulse Width Modulation Output
fPWM PWM frequency Signal period = 4098µs ±10% at TAMB
= -40 to +150ºC 220 244 268 Hz
PWMIN Minimum pulse width Position 0d; angle 0 degree 0.90 1 1.10 µs
PWMAX Maximum pulse width Position 4098d; angle 359.91 degrees 3686 4096 4506 µs
Programming Conditions
tPROG Programming time per bit Time to prog. a singe fuse bit 10 20 µs
tCHARGE Refresh time per bit Time to charge the cap after tPROG 1µs
fLOAD LOAD frequency Data can be loaded at n x 2µs 500 kHz
fREAD READ frequency Read the data from the latch 2.5 MHz
fWRITE WRITE frequency Write the data to the latch 2.5 MHz
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AS5245
Data Sheet - Detailed Description
8 Detailed Description
The AS5245 is manufactured in a CMOS standard process and uses a spinning current Hall technology for sensing the magnetic field
distribution across the surface of the chip. The integrated Hall elements are placed around the center of the device and deliver a voltage
representation of the magnetic field at the surface of the IC.
Through Sigma-Delta Analog / Digital Conversion and Digital Signal-Processing (DSP) algorithms, the AS5245 provides accurate high-resolution
absolute angular position information. For this purpose, a Coordinate Rotation Digital Computer (CORDIC) calculates the angle and the
magnitude of the Hall array signals. The DSP is also used to provide digital information at the outputs MagINCn and MagDECn that indicate
movements of the used magnet towards or away from the device’s surface. A small low cost diametrically magnetized (two-pole) standard
magnet provides the angular position information (see Figure 16).
The AS5245 senses the orientation of the magnetic field and calculates a 12-bit binary code. This code can be accessed via. a Synchronous
Serial Interface (SSI). In addition, an absolute angular representation is given by a Pulse Width Modulated signal at pin 12 (PWM). This PWM
signal output also allows the generation of a direct proportional analog voltage, by using an external Low-Pass-Filter. The AS5245 is tolerant to
magnet misalignment and magnetic stray fields due to differential measurement technique and Hall sensor conditioning circuitry.
Figure 4. Typical Arrangement of AS5245 and Magnet
8.1 Mode_Index Pin
The Mode_Index pin activates or deactivates an internal filter that is used to reduce the analog output noise. Activating the filter (Mode pin =
LOW or open) provides a reduced output noise of 0.03º rms. At the same time, the output delay is increased to 384µs. This mode is
recommended for high precision, low speed applications.
Deactivating the filter (Mode pin = HIGH) reduces the output delay to 96µs and provides an output noise of 0.06º rms. This mode is
recommended for higher speed applications.
Setting up the Mode pin affects the following parameters:
Note: A change of the Mode during operation is not allowed. The setup must be constant during power up and during operation.
Table 6. Slow and Fast Mode Parameters
Parameter Slow Mode (mode=low or open) Fast Mode (mode=high, VDD=5V)
Sampling rate 2.61 kHz (384 µs) 10.42 kHz (96µs)
Transition noise (1 sigma) ≤ 0.03º rms ≤ 0.06º rms
Output delay 384µs 96µs
Maximum speed @ 4096 samples/rev 38 rpm 153 rpm
Maximum speed @ 1024 samples/rev 153 rpm 610 rpm
Maximum speed @ 256 samples/rev 610 rpm 2441 rpm
Maximum speed @ 64 samples/rev 2441 rpm 9766 rpm
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AS5245
Data Sheet - Detailed Description
8.2 Synchronous Serial Interface (SSI)
Figure 5. Synchronous Serial Interface with Absolute Angular Position Data
If CSn changes to logic low, Data Out (DO) will change from high impedance (tri-state) to logic high and the read-out will be initiated.
After a minimum time tCLK FE, data is latched into the output shift register with the first falling edge of CLK.
Each subsequent rising CLK edge shifts out one bit of data.
The serial word contains 18 bits, the first 12 bits are the angular information D[11:0], the subsequent 6 bits contain system information,
about the validity of data such as OCF, COF, LIN, Parity and Magnetic Field status (increase/decrease).
A subsequent measurement is initiated by a “high” pulse at CSn with a minimum duration of tCSn.
8.2.1 Serial Data Contents
D11:D0 – Absolute angular position data (MSB is clocked out first).
OCF – (Offset Compensation Finished). Logic high indicates the finished Offset Compensation Algorithm.
COF – (Cordic Overflow). Logic high indicates an out of range error in the CORDIC part. When this bit is set, the data at D9:D0 is invalid. The
absolute output maintains the last valid angular value. This alarm may be resolved by bringing the magnet within the X-Y-Z tolerance limits.
LIN – (Linearity Alarm). Logic high indicates that the input field generates a critical output linearity. When this bit is set, the data at D9:D0 may still
be used, but can contain invalid data. This warning may be resolved by bringing the magnet within the X-Y-Z tolerance limits.
Even Parity – Bit for transmission error detection of bits 1…17 (D11…D0, OCF, COF, LIN, MagINC, MagDEC). Placing the magnet above the
chip, angular values increase in clockwise direction by default.
Data D11:D0 is valid, when the status bits have the following configurations:
Note: MagInc=MagDec=1 is only recommended in YELLOW mode (see Table 8)
Table 7. Status Bit Outputs
OCF COF LIN Mag INC Mag DEC Parity
10 0
00
Even checksum of bits
1:15
01
10
11
CSn
CLK
DO
tDO valid
Angular Position Data
tDO active Status Bits
tDO Tristate
tCSn
tCLKFE
tCLKFE
TCLK/2
1
D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 OCF COF LIN Mag
INC
Mag
DEC
Even
PAR
818
1
D11D10
D11
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AS5245
Data Sheet - Detailed Description
8.2.2 Z-axis Range Indication (Push Button Feature, Red/Yellow/Green Indicator)
The AS5245 provides several options of detecting movement and distance of the magnet in the Z-direction. Signal indicators MagINCn and
MagDECn are available both as hardware pins (pins #1 and 2) and as status bits in the serial data stream (see Figure 5). Additionally, an OTP
programming option is available with bit MagCompEn that enables additional features:
In the default state, the status bits MagINC, MagDec and pins MagINCn, MagDECn have the following function:
Note: Pin 1 (MagINCn) and pin 2 (MagDECn) are active low via. open drain output and require an external pull-up resistor. If the magnetic
field is in range, both outputs are turned off.
The two pins may also be combined with a single pull-up resistor. In this case, the signal is high when the magnetic field is in range. It is low in all
other cases (see Table 8).
8.2.3 Incremental Mode
The AS5245 has an internal interpolator block. This function is used if the input magnetic field is too fast and a code position is missing. In this
case an interpolation is done.
With the OTP bits OutputMd0 and OutputMd1 a specific mode can be selected. For the available pre-programmed incremental versions (10bit
and 12bit), these bits are set during test at austriamicrosystems. These settings are permanent and can not be recovered.
A change of the incremental mode (WRITE command) during operation could cause problems. A power-on-reset in between is recommended.
During operation in incremental mode it is recommended setting CSn = High, to disable the SSI-Interface.
Table 8. Magnetic Field Strength Red-Yellow-Green Indicator (OTP option)
Status Bits Hardware Pins OPT: Mag CompEn = 1 (Red-Yellow-Green Programming Option)
Mag
INC Mag
DEC LIN Mag
INCn Mag
DECn Description
000OffOff
No distance change
Magnetic input field OK (GREEN range, ~45…75mT)
110OnOff
YELLOW range: magnetic field is ~ 25…45mT or ~75…135mT. The AS5245
may still be operated in this range, but with slightly reduced accuracy.
111OnOn
RED range: magnetic field is ~<25mT or >~135mT. It is still possible to
operate the AS5245 in the red range, but not recommended.
All other combinations n/a n/a Not available
Table 9. Incremental Resolution
Mode Description Output
Md1 Output
Md0 Resolution
DTest1_A
and
DTest2_B
Pulses
Index Width
Default mode
AS5245 function DTEST1_A and
DTEST2_B are not used. The
Mode_Index pin is used for selection of
the decimation rate (low speed/high
speed).
00
10 bit
Incremental
mode
(low DNL)
DTEST1_A and DTEST2_B are used as
A and B signal. In this mode the
Mode_Index Pin is switched from input
to output and will be the Index Pin. The
decimation rate is set to 64 (fast mode)
and cannot be changed from external.
0 1 10 256
1/3
LSB
12 bit
Incremental
mode (high
DNL)
1 0 12 1024
Sync mode In this mode a control signal is switched
to DTEST1_A and DTEST2_B. 11
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AS5245
Data Sheet - Detailed Description
Figure 6. Incremental Output
The hysteresis trimming is done at the final test (factory trimming) and set to 4 LSB, related to a 12 bit number.
Incremental Output Hysteresis. To avoid flickering incremental outputs at a stationary magnet position, a hysteresis is introduced. In case
of a rotational direction change, the incremental outputs have a hysteresis of 4 LSB. Regardless of the programmed incremental resolution, the
hysteresis of 4 LSB always corresponds to the highest resolution of 12 bit. In absolute terms, the hysteresis is set to 0.35 degrees for all
resolutions. For constant rotational directions, every magnet position change is indicated at the incremental outputs (see Figure 7). For example,
if the magnet turns clockwise from position “x+3“ to “x+4“, the incremental output would also indicate this position accordingly. A change of the
magnet’s rotational direction back to position “x+3“ means that the incremental output still remains unchanged for the duration of 4 LSB, until
position “x+2“is reached. Following this direction, the incremental outputs will again be updated with every change of the magnet position.
Figure 7. Hysteresis Window for Incremental Outputs
Mode_Index
D Test2_B
D Test1_A
1 LSB
Programmed
Zero Position
ClockWise
3 LSB
Counter ClockWise
Magnet Position
Hysteresis :
0.35°
X +2
Incremental
Output
Indication
Clockwise Direction
Counterc lockwis e Dir ec tion
X +4
XX X +2 X +4 X +5X +3X +1
X +1
X +3
X +6
X +5
X +6
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AS5245
Data Sheet - Detailed Description
Incremental Output Validity. During power on the incremental output is kept stable high until the offset compensation is finished and the
CSn is low (internal Pull Up) the first time. In quadrature mode A = B = Index = high indicates an invalid output. If the interpolator recognizes a
difference larger than 128 steps between two samples, it holds the last valid state. The interpolator synchronizes up again with the next valid
difference. This avoids undefined output burst, e.g. if no magnet is present.
8.2.4 Sync Mode
This mode is used to synchronize the external electronic with the AS5245. In this mode, two signals are provided at the pins DTEST1_A and
DTEST2_B. By setting of Md0=1 and Md1=1 in the OTP register, the Sync mode will be activated.
Figure 8. DTest1_A and DTest2_B
Every rising edge at DTEST1_A indicates that new data in the device is available. With this signal it is possible to trigger an external customer
Microcontroller (interrupt) and start the SSI readout. DTEST2_B indicates the phase of available data.
8.2.5 Sine/Cosine Mode
This mode can be enabled by setting the OTP Factory-bit FS2. If this mode is activated, the 16 bit sinus and 16 bit cosines digital data of both
channels will be switched out. Due to the high resolution of 16 bits of the data stream, an accurate calculation can be done externally. In this
mode, the open drain outputs of DTEST1_A and DTEST2_B are switched to push-pull mode. At Pin MagDECn the clock impulse, at Pin
MagINCn the Enable pulse will be switched out. The pin PWM indicates, which phase of signal is being presented. The mode is not available in
the default mode.
8.2.6 Daisy Chain Mode
The Daisy Chain mode allows connection of several AS5245s in series, while still keeping just one digital input for data transfer (see “Data IN” in
Figure 9). This mode is accomplished by connecting the data output (DO; pin 9) to the data input (PDIO; pin 8) of the subsequent device. The
serial data of all connected devices is read from the DO pin of the first device in the chain. The length of the serial bit stream increases with every
connected device, it is n * (18+1) bits: n= number of devices. E.g. 38 bit for two devices, 57 bit for three devices, etc.
The last data bit of the first device (Parity) is followed by a dummy bit and the first data bit of the second device (D11), etc. (see Figure 10).
Figure 9. Daisy Chain Hardware Configuration
DTest1_A
DTest1_B
400µs (100µs)
CSn
CSn CSn CSn
CLK CLK CLK
CLK
Data IN
AS5245
Top Die AS5245
Bottom Die AS5245
Top Die
µC
DO DO DO
PDIO PDIO PDIO
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Data Sheet - Detailed Description
Figure 10. Da isy Chain Mode Data Transfer
8.3 Pulse Width Modulation (PWM) Output
The AS5245 provides a pulse width modulated output (PWM), whose duty cycle is proportional to the measured angle. For angle position 0 to
4094:
Position = (EQ 1)
Examples:
1. An angle position of 180º will generate a pulse width ton = 2049µs and a pause tOFF of 2049 µs resulting in Position = 2048 after the
calculation: 2049 * 4098 / (2049 + 2049) -1 = 2048
2. An angle position of 359.8º will generate a pulse width ton = 4095µs and a pause tOFF of 3 µs resulting in Position = 4094 after the cal-
culation: 4095 * 4098 / (4095 + 3) -1 = 4094
Exception:
1. An angle position of 359.9º will generate a pulse width ton = 4097µs and a pause tOFF of 1 µs resulting in Position = 4096 after the cal-
culation: 4097 * 4098 / (4097 + 1) -1 = 4096
The PWM frequency is internally trimmed to an accuracy of ±5% (±10% over full temperature range). This tolerance can be cancelled by
measuring the complete duty cycle as shown above.
Figure 11. PWM Output Signal
CSn
CLK
DO
tDO valid
Angular Position Data
tDO active Status Bits
tCLK FE
TCLK/2
1
D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 OCF COF LIN Mag
INC
Mag
DEC
Even
PAR
818 D
D11
123
D10 D9
Angular Position Data
1st Device 2nd Device
D10
D11
ton 4098⋅
ton toff
+()
------------------------- 1–
4097µs
4096µs
1/fPWM
PWMAX
PWMIN
359.91 deg
(Pos 4095)
0 deg
(Pos 0)
Angle
1µs
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Data Sheet - Detailed Description
8.3.1 Changing the PWM Frequency
The PWM frequency of the AS5245 can be divided by two by setting a bit (PWMhalfEN) in the OTP register (see Programming the AS5245 on
page 17). With PWMhalfEN = 0, the PWM timing is as shown in Table 10:
When PWMhalfEN = 1, the PWM timing is as shown in Table 11:
8.4 Analog Output
An analog output can be generated by averaging the PWM signal, using an external active or passive low pass filter. The analog output voltage
is proportional to the angle: 0º= 0V; 360º = VDD5V.
Using this method, the AS5245 can be used as direct replacement of potentiometers.
Figure 12. Simple 2nd Order Passive RC Low Pass Filter
Figure 12 shows an example of a simple passive low pass filter to generate the analog output.
R1,R2
≥
4k7 C1,C2
≥
1µF / 6V (EQ 2)
R1 should be greater than or equal to 4k7 to avoid loading of the PWM output. Larger values of Rx and Cx will provide better filtering and less
ripple, but will also slow down the response time.
Table 10. PWM Signal Parameters (Default mode)
Symbol Parameter Typ Unit Note
fPWM PWM frequency 244 Hz Signal period: 4097µs
PWMIN MIN pulse width 1 µs - Position 0d
- Angle 0 deg
PWMAX MAX pulse width 4096 µs - Position 4095d
- Angle 359,91 deg
Table 11. PWM Signal Parameters with Half Frequency (OTP option)
Symbol Parameter Typ Unit Note
fPWM PWM frequency 122 Hz - Position 0d
- Angle 0 deg
PWMIN MIN pulse width 2 µs - Position 4095d
- Angle 359,91 deg
PWMAX MAX pulse width 8192 µs - Position 0d
- Angle 0 deg
R1 R2 analog out
Pin12
PWM
Pin7
VSS
C1 C2
VDD
0V
0º 360º
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AS5245
Data Sheet - Application Information
9 Application Information
The benefits of AS5245 are as follows:
Complete system-on-chip
Angle measurement with programmable range up to 360º
High reliability due to non-contact magnetic sensing
Ideal for applications in harsh environments
Robust system, tolerant to magnet misalignment, airgap variations, temperature variations and external magnetic fields
No calibration required
Building of redundancy systems with plausibility checks
9.1 Programming the AS5245
After power-on, programming the AS5245 is enabled with the rising edge of CSn with PDIO = high and CLK = low.
The AS5245 programming is a one-time programming (OTP) method, based on poly silicon fuses. The advantage of this method is that a
programming voltage of only 3.3V to 3.6V is required for programming.
The OTP consists of 52 bits, of which 21 bits are available for user programming. The remaining 31 bits contain factory settings and a unique
chip identifier (Chip-ID).
A single OTP cell can be programmed only once. Per default, the cell is “0”; a programmed cell will contain a “1”. While it is not possible to reset
a programmed bit from “1” to “0”, multiple OTP writes are possible, as long as only unprogrammed “0”-bits are programmed to “1”.
Independent of the OTP programming, it is possible to overwrite the OTP register temporarily with an OTP write command at any time. This
setting will be cleared and overwritten with the hard programmed OTP settings at each power-up sequence or by a LOAD operation. Use
application note AN514X_10 to get more information about the programming options.
The OTP memory can be accessed in the following ways:
Load Operation: The Load operation reads the OTP fuses and loads the contents into the OTP register. A Load operation is automatically
executed after each power-on-reset.
Write Operation: The Write operation allows a temporary modification of the OTP register. It does not program the OTP. This operation can
be invoked multiple times and will remain set while the chip is supplied with power and while the OTP register is not modified with another
Write or Load operation.
Read Operation: The Read operation reads the contents of the OTP register, for example to verify a Write command or to read the OTP
memory after a Load command.
Program Operation: The Program operation writes the contents of the OTP register permanently into the OTP ROM.
Analog Readback Operation: The Analog Readback operation allows a quantifiable verification of the programming. For each
programmed or unprogrammed bit, there is a representative analog value (in essence, a resistor value) that is read to verify whether a bit
has been successfully programmed or not.
9.1.1 Zero Position Programming
Zero position programming is an OTP option that simplifies assembly of a system, as the magnet does not need to be manually adjusted to the
mechanical zero position. Once the assembly is completed, the mechanical and electrical zero positions can be matched by software. Any
position within a full turn can be defined as the permanent new zero position.
For zero position programming, the magnet is turned to the mechanical zero position (e.g. the “off”-position of a rotary switch) and the actual
angular value is read.
This value is written into the OTP register bits Z35:Z46.
Note: The zero position value may also be modified before programming, e.g. to program an electrical zero position that is 180º (half turn)
from the mechanical zero position, just add 2048 to the value read at the mechanical zero position and program the new value into the
OTP register.
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Data Sheet - Application Information
9.1.2 OTP Memory Assignment
9.1.3 User Selectable Settings
The AS5245 allows programming of the following user selectable options:
-PWMhalfEN_Indexwidth: Setting this bit, the PWM pulse will be divided by 2, in case of quadrature incremental mode A/B/Index setting
of Index impulse width from 1 LSB to 3LSB.
-MagCompEN: The green/yellow mode can be enabled by setting of this bit.
-Output Md0: Setting this bit enables sync- or 10bit incremental mode (see Table 9). It is already set by Austriamicrosystems.
-Output Md1: Setting this bit enables sync- or 12bit incremental mode (see Table 9)
-Z [11:0]: Programmable Zero / Index Position
-CCW: Counter Clockwise Bit
ccw=0 – angular value increases in clockwise direction
ccw=1 – angular value increases in counterclockwise direction
-RA [4:0]: Redundant Address: an OTP bit location addressed by this address is always set to “1” independent of the corresponding
original OTP bit setting
Table 12. OTP Bit Assignment
Bit Symbol Function
mbit1 Factory Bit 1
51 PWMhalfEN_Index width PMW frequency Index pulse width
Customer Section
50 MagCompEn Alarm mode
49 pwmDIS Disable PWM
48 Output Md0 Default, 10 bit inc, 12 bit inc
47 Output Md1 Sync mode
46 Z0
12 bit Zero Position::
35 Z11
34 CCW Direction
33 RA0
Redundancy Address::
29 RA4
28 FS 0
Factory Bit
Factory Section
27 FS 1
26 FS 2
25 FS 3
24 FS 4
23 FS 5
::
20 FS 9
17 ChipID0
18 bit Chip ID
ID Section
16 ChipID1
::
0ChipID17
mbit0 Factory Bit 0
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Data Sheet - Application Information
9.1.4 OTP Default Setting
The AS5245 can also be operated without programming. The default, un-programmed setting is:
-Output Md0, Output MD1: 00= Default mode
-Z0 to Z11: 00 = no programmed zero position
-CCW: 0 = clockwise operation
-RA4 to RA0:0 = no OTP bit is selected
-MagCompEN: 1 = The green / yellow mode is enabled.
9.1.5 Redundancy
For a better programming reliability, a redundancy is implemented. This function can be used in cases where the programming of one bit fails.
With an address RA(4:0), one bit can be selected and programmed.
9.1.6 Redundant Programming Option
In addition to the regular programming, a redundant programming option is available. This option allows that one selectable OTP bit can be set
to “1” (programmed state) by writing the location of that bit into a 5-bit address decoder. This address can be stored in bits RA4…RA0 in the OTP
user settings.
Example: setting RA4…0 to “00001” will select bit 51 = PWhalfEN_Indexwidth, “00010” selects bit 50 = MagCompEN, “10010” selects bit 34
=CCW, etc.
Table 13. Redundancy Addressing
Address
PWMhalfEN_Indexwidth
MagCompEN
pwmDIS
Output Md0
Output Md1
Z0 Z1 Z2 Z3 Z4 Z5 Z6 Z7 Z8 Z9 Z10 Z11 CCW
00000 00000000000000000 0
00001 10000000000000000 0
00010 0 1000000000000000 0
00011 0 0 100000000000000 0
00100 0 0 0 10000000000000 0
00101 00001000000000000 0
00110 00000100000000000 0
00111 00000010000000000 0
01000 00000001000000000 0
01001 00000000100000000 0
01010 00000000010000000 0
01011 00000000001000000 0
01100 00000000000100000 0
01101 00000000000010000 0
01110 00000000000001000 0
01111 00000000000000100 0
10000 000000000000000100
10001 000000000000000010
10010 00000000000000000 1
10101 11111111111111111 1
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Data Sheet - Application Information
9.2 Alignment Mode
The alignment mode simplifies centering the magnet over the center of the chip to gain maximum accuracy.
Alignment mode can be enabled with the falling edge of CSn while PDIO = logic high (see Figure 13). The Data bits D11-D0 of the SSI change to
a 12-bit displacement amplitude output. A high value indicates large X or Y displacement, but also higher absolute magnetic field strength. The
magnet is properly aligned, when the difference between highest and lowest value over one full turn is at a minimum.
Under normal conditions, a properly aligned magnet will result in a reading of less than 128 over a full turn.
The MagINCn and MagDECn indicators will be = 1 when the alignment mode reading is < 128. At the same time, both hardware pins MagINCn
(#1) and MagDECn (#2) will be pulled to VSS. A properly aligned magnet will therefore produce a MagINCn = MagDECn = 1 signal throughout a
full 360º turn of the magnet.
Stronger magnets or short gaps between magnet and IC may show values larger than 128. These magnets are still properly aligned as long as
the difference between highest and lowest value over one full turn is at a minimum.
The Alignment mode can be reset to normal operation by a power-on-reset (disconnect / re-connect power supply) or by a falling edge on CSn
with PDIO = low.
Figure 13. Enabling the Alignment Mode
Figure 14. Exiting Alignment Mode
PDIO
CSn
AlignMode enable Read-out
via SSI
2µs
min.
2µs
min.
PDIO
CSn
exit AlignMode Read-out
via SSI
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Data Sheet - Application Information
9.3 3.3V / 5V Operation
The AS5245 operates either at 3.3V ±10% or at 5V ±10%. This is made possible by an internal 3.3V Low-Dropout (LDO) Voltage regulator. The
internal supply voltage is always taken from the output of the LDO, meaning that the internal blocks are always operating at 3.3V.
For 3.3V operation, the LDO must be bypassed by connecting VDD3V3 with VDD5V (see Figure 15).
For 5V operation, the 5V supply is connected to pin VDD5V, while VDD3V3 (LDO output) must be buffered by a 1...10µF capacitor, which is
supposed to be placed close to the supply pin (see Figure 15).
Note: The VDD3V3 output is intended for internal use only. It must not be loaded with an external load.
The output voltage of the digital interface I/O’s corresponds to the voltage at pin VDD5V, as the I/O buffers are supplied from this pin.
Figure 15. Connections for 5V / 3.3V Supply Voltages
A buffer capacitor of 100nF is recommended in both cases close to pin VDD5V. Note that pin VDD3V3 must always be buffered by a capacitor. It
must not be left floating, as this may cause an instable internal 3.3V supply voltage, which may lead to larger than normal jitter of the measured
angle.
Internal
VDD
LDO
I
N
T
E
R
F
A
C
E
VSS
VDD5V
VDD3V3
100n
4.5 - 5.5V
+
-
1... 10µF
DO
PWM
CLK
CSn
PDIO
Internal
VDD
LDO
I
N
T
E
R
F
A
C
E
VSS
VDD5V
VDD3V3
3.0 - 3.6V
+
-
DO
PWM
CLK
CSn
PDIO
100n
5V Operation 3.3V Operation
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Data Sheet - Application Information
9.4 Choosing the Proper Magnet
Typically, the magnet should be 6mm in diameter and ≥ 2.5mm in height. Magnetic materials such as rare earth AlNiCo/SmCo5 or NdFeB are
recommended. The magnetic field strength perpendicular to the die surface has to be in the range of ±45mT…±75mT (peak).
The magnet’s field strength should be verified using a gauss-meter. The magnetic field Bv at a given distance, along a concentric circle with a
radius of 1.1mm (R1), should be in the range of ±45mT…±75mT (see Figure 16).
Figure 16. Typical Magnet (6x3mm) and Magnetic Field Distribution
Magnet axis
Vertical field
component
(45…75mT)
0
360
360
Bv
Vertical field
component
R1 concentric circle;
radius 1.1mm
R1
Magnet axis
typ. 6mm diameter
SN
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Data Sheet - Application Information
9.5 Failure Diagnostics
The AS5245 also offers several diagnostic and failure detection features, which are discussed in detail further in the document.
9.5.1 Magnetic Field Strength Diagnosis
By Software: The MagINC and MagDEC status bits will both be high when the magnetic field is out of range.
By Hardware: Pins #1 (MagINCn) and #2 (MagDECn) are open-drain outputs and will both be turned on (= low with external pull-up resistor)
when the magnetic field is out of range. If only one of the outputs are low, the magnet is either moving towards the chip (MagINCn) or away from
the chip (MagDECn).
9.5.2 Power Supply Failure Detection
By Software: If the power supply to the AS5245 is interrupted, the digital data read by the SSI will be all “0”s. Data is only valid, when bit OCF is
high, hence a data stream with all “0”s is invalid. To ensure adequate low levels in the failure case, a pull-down resistor (~10kΩ) should be added
between pin DIO and VSS at the receiving side.
By Hardware: The MagINCn and MagDECn pins are open drain outputs and require external pull-up resistors. In normal operation, these pins
are high ohmic and the outputs are high (see Table 8). In a failure case, either when the magnetic field is out of range of the power supply is
missing, these outputs will become low. To ensure adequate low levels in case of a broken power supply to the AS5245, the pull-up resistors
(~10kΩ) from each pin must be connected to the positive supply at pin 16 (VDD5V).
By Hardware, PWM Output: The PWM output is a constant stream of pulses with 1kHz repetition frequency. In case of power loss, these pulses
are missing.
9.6 Angular Output Tolerances
9.6.1 Accuracy
Accuracy is defined as the error between measured angle and actual angle. It is influenced by several factors:
The non-linearity of the analog-digital converters,
Internal gain and mismatch errors,
Non-linearity due to misalignment of the magnet.
As a sum of all these errors, the accuracy with centered magnet = (Errmax – Errmin)/2 is specified as better than ±0.5 degrees @ 25ºC (see
Figure 19).
Misalignment of the magnet further reduces the accuracy. Figure 18 shows an example of a 3D-graph displaying non-linearity over XY-
misalignment. The center of the square XY-area corresponds to a centered magnet (see dot in the center of the graph). The X- and Y- axis
extends to a misalignment of ±1mm in both directions. The total misalignment area of the graph covers a square of 2x2 mm (79x79mil) with a
step size of 100µm.
For each misalignment step, the measurement as shown in Figure 19 is repeated and the accuracy (Errmax – Errmin)/2 (e.g. 0.25º in Figure 19) is
entered as the Z-axis in the 3D-graph.
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Data Sheet - Application Information
Figure 17. Example of Linearity Error Over XY Misalignment
The maximum non-linearity error on this example is better than ±1 degree (inner circle) over a misalignment radius of ~0.7mm. For volume
production, the placement tolerance of the IC within the package (±0.235mm) must also be taken into account. The total nonlinearity error over
process tolerances, temperature and a misalignment circle radius of 0.25mm is specified better than ±1.4 degrees. The magnet used for this
measurement was a cylindrical NdFeB (Bomatec® BMN-35H) magnet with 6mm diameter and 2.5mm in height.
-1000
-700
-400
-100
200
500
800
-1000
-800
-600
-400
-200
0
200
400
600
800
1000
0
1
2
3
4
5
6
°
x
y
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Data Sheet - Application Information
Figure 18. Example of Linearity Error Over 360º
9.6.2 Transition Noise
Transition noise is defined as the jitter in the transition between two steps. Due to the nature of the measurement principle (Hall sensors +
Preamplifier + ADC), there is always a certain degree of noise involved. This transition noise voltage results in an angular transition noise at the
outputs. It is specified as 0.06 degrees rms (1 sigma)1 in fast mode (pin MODE = high) and 0.03 degrees rms (1 sigma) in slow mode (pin MODE
= low or open). This is the repeatability of an indicated angle at a given mechanical position. The transition noise has different implications on the
type of output that is used:
Absolute Output; SSI Interface: The transition noise of the absolute output can be reduced by the user by implementing averaging of
readings. An averaging of 4 readings will reduce the transition noise by 6dB or 50%, e.g. from 0.03º rms to 0.015º rms (1 sigma) in slow
mode.
PWM Interface: If the PWM interface is used as an analog output by adding a low pass filter, the transition noise can be reduced by lower-
ing the cutoff frequency of the filter. If the PWM interface is used as a digital interface with a counter at the receiving side, the transition
noise may again be reduced by averaging of readings.
Incremental Mode: In incremental mode, the transition noise influences the period, width and phase shift of the output signals A, B and
Index. However, the algorithm used to generate the incremental outputs guarantees no missing or additional pulses even at high speeds (up
to 30.000 rpm and higher).
9.6.3 High Speed Operation
Sampling Rate. The AS5245 samples the angular value at a rate of 2.61k (slow mode) or 10.42k (fast mode, selectable by pin MODE)
samples per second. Consequently, the absolute outputs are updated each 384µs (96µs in fast mode). At a stationary position of the magnet,
the sampling rate creates no additional error.
Absolute Mode. At a sampling rate of 2.6kHz/10.4kHz, the number of samples (n) per turn for a magnet rotating at high speed can be
calculated by,
nslowmode = (EQ 3)
nfastmode = (EQ 4)
The upper speed limit in slow mode is ~6.000rpm and ~30.000rpm in fast mode. The only restriction at high speed is that there will be fewer
samples per revolution as the speed increases (see Table 6). Regardless of the rotational speed, the absolute angular value is always sampled
at the highest resolution of 12 bit.
1. Statistically, 1 sigma represents 68.27% of readings; 3 sigma represents 99.73% of readings.
-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
0.5
1 55 109 163 217 271 325 379 433 487 541 595 649 703 757 811 865 919 973
transition noise
Err
max
Err
min
60
rpm 384()μs⋅
-----------------------------------
60
rmp 96μs⋅
---------------------------
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Incremental Mode. Incremental encoders are usually required to produce no missing pulses up to several thousand rpms. Therefore, the
AS5245 has a built-in interpolator, which ensures that there are no missing pulses at the incremental outputs for rotational speeds of up to
30.000 rpm, even at the highest resolution of 10 bits (512 pulses per revolution).
9.6.4 Propagation Delays
The propagation delay is the delay between the time that the sample is taken until it is converted and available as angular data. This delay is
96µs in fast mode and 384µs in slow mode.
Using the SSI interface for absolute data transmission, an additional delay must be considered, caused by the asynchronous sampling (0 … 1/
fsample) and the time it takes the external control unit to read and process the angular data from the chip (maximum clock rate = 1MHz, number
of bits per reading = 18).
Angular Error Caused by Propagation Delay. A rotating magnet will cause an angular error caused by the output propagation delay.
This error increases linearly with speed:
esampling = rpm * 6 * pr op.delay (EQ 5)
Where:
esampling = angular error [º]
rpm = rotating speed [rpm]
prop.delay = propagation delay [seconds]
Note: Since the propagation delay is known, it can be automatically compensated by the control unit processing the data from the AS5245.
9.6.5 Internal Timing Tolerance
The AS5245 does not require an external ceramic resonator or quartz. All internal clock timings for the AS5245 are generated by an on-chip RC
oscillator. This oscillator is factory trimmed to ±5% accuracy at room temperature (±10% over full temperature range). This tolerance influences
the ADC sampling rate and the pulse width of the PWM output:
Absolute Output; SSI Interface: A new angular value is updated every 96µs (typ) in fast mode and every 384µs (typ) in slow mode.
PWM Output: A new angular value is updated every 400µs (typ). The PWM pulse timings tON and tOFF also have the same tolerance as
the internal oscillator. If only the PWM pulse width tON is used to measure the angle, the resulting value also has this timing tolerance.
However, this tolerance can be cancelled by measuring both tON and tOFF and calculating the angle from the duty cycle (see Pulse Width
Modulation (PWM) Output on page 15).
Incremental Mode: In incremental mode, the transition noise influences the period, width and phase shift of the output signals A, B and
Index. However, the algorithm used to generate the incremental outputs guarantees no missing or additional pulses even at high speeds (up
to 30.000 rpm and higher).
Position = (EQ 6)
9.6.6 Temperature
Magnetic Temperature Coefficient. One of the major benefits of the AS5245 compared to linear Hall sensors is that it is much less
sensitive to temperature. While linear Hall sensors require a compensation of the magnet’s temperature coefficients, the AS5245 automatically
compensates for the varying magnetic field strength over temperature. The magnet’s temperature drift does not need to be considered, as the
AS5245 operates with magnetic field strengths from ±45…±75mT.
Example:
A NdFeB magnet has a field strength of 75mT @ -40ºC and a temperature coefficient of -0.12% per Kelvin. The temperature change is from -40º
to +125º = 165K.The magnetic field change is: 165 x -0.12% = -19.8%, which corresponds to 75mT at -40ºC and 60mT at 125ºC.
The AS5245 can compensate for this temperature related field strength change automatically, no user adjustment is required.
9.6.7 Accuracy over Temperature
The influence of temperature in the absolute accuracy is very low. While the accuracy is less than or equal to ±0.5º at room temperature, it may
increase to less then or equal to ±0.9º due to increasing noise at high temperatures.
ton 4097⋅
ton toff
+()
------------------------- 1–
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AS5245
Data Sheet - Application Information
Timing Tolerance over Temperature. The internal RC oscillator is factory trimmed to ±5%. Over temperature, this tolerance may increase
to ±10%. Generally, the timing tolerance has no influence in the accuracy or resolution of the system, as it is used mainly for internal clock
generation. The only concern to the user is the width of the PWM output pulse, which relates directly to the timing tolerance of the internal
oscillator. This influence, however, can be cancelled by measuring the complete PWM duty cycle instead of just the PWM pulse.
9.7 AS5245 Differences to AS5045
All parameters are according to AS5045 data sheet except for the parameters shown below:
Table 14. Difference Between AS5245 and AS5045
Building Block AS5245 AS5045
Resolution 12bits, 0.088º/step. 12bits, 0.088º/step.
Ambient temperature range -40ºC to +150ºC -40ºC to +125ºC
Data length
read: 18bits
(12bits data + 6 bits status)
OTP write: 18 bits
(12bits zero position + 6 bits mode selection)
read: 18bits
(12bits data + 6 bits status)
OTP write: 18 bits
(12bits zero position + 6 bits mode selection)
Pins 1 and 2
MagINCn, MagDECn: same feature as AS5045,
additional OTP option for red-yellow-green magnetic
range
MagINCn, MagDECn
Incremental encoder
Pin3 (DTest1_A); Pin 4 (DTest2_B); Pin 6 (Mode_Index)
2x1024 ppr (12-bit)
2x256 ppr low-jitter (10-bit)
Not used
Pin 3: not used
Pin 4:not used
Pin 6
MODE_Index pin selects fast or slow mode in the
default configuration. In case of incremental mode, the
fast mode is selected and the pin is configured as
output.
MODE_Index pin selects fast or slow mode in the
default configuration.
Pin 12
PWM output: frequency selectable by OTP:
1µs / step, 4096 steps per revolution, f=244Hz 2µs/
step, 4096 steps per revolution, f=122Hz
PWM output: frequency selectable by OTP:
1µs / step, 4096 steps per revolution, f=244Hz
2µs/ step, 4096 steps per revolution, f=122Hz
Sampling frequency selectable by MODE input pin:
2.5kHz, 10,4kHz
selectable by MODE input pin:
2.5kHz, 10,4kHz
Propagation delay 384µs (slow mode) 384µs (slow mode)
96µs (fast mode) 96µs (fast mode)
Transition noise
(rms; 1sigma)
0.03 degrees maximum (slow mode) 0.03 degrees maximum (slow mode)
0.06 degrees maximum (fast mode) 0.06 degrees maximum (fast mode)
OTP programming options
PPTRIM; programming voltage 3.3V – 3.6V <70ºC;
3.5V – 3.6V >70ºC;
52-bit serial data protocol; CSn, PDIO and CLK
EasyZap; programming voltage 7.3V – 7.5V; Csn;
Prog and CLK; 16-bit (32-bit) serial data protocol;
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AS5245
Data Sheet - Package Drawings and Markings
10 Package Drawings and Markings
The device is available in a QFN 32 (7mm x 7mm) package.
Figure 19. Package Drawings
Table 15. Package Dimensions
Symbol mm inch
Min Typ Max Min Typ Max
D 7 BSC 0.28 BSC
E 7 BSC 0.28 BSC
D1 4.18 4.28 4.38 0.165 0.169 0.172
E1 4.18 4.28 4.38 0.165 0.169 0.172
L 0.45 0.55 0.65 0.018 0.022 0.026
b 0.25 0.30 0.35 0.010 0.012 0.014
e 0.65 BSC
A 0.80 0.90 1.00 0.031 0.035 0.039
A1 0.203 REF 0.008 REF
25 32
8
1
16 9
17
24
AS5245
Top View
Side View
B
otto
m Vi
e
w
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AS5245
Data Sheet - Revision History
Revision History
Note: Typos may not be explicitly mentioned under revision history.
Revision Date Owner Description
1.0
June 08, 2007
apg
Initial revision
July 24, 2008 Changes made to values in Table 9 - Incremental Resolution
Feb 13, 2009 Updated min, typ, max values for tDOvalid parameter in Table 5 - Timing
Characteristics
July 15, 2009 rfu
1) Note added under Table 6 - Slow and Fast Mode Parameters
2) Output Md0, Md1 description updated, (see User Selectable Settings
on page 18)
July 22, 2009
mub
Updated values in Table 5 - Timing Characteristics for the following
parameters:
-t
DOvalid
-f
PWM
-PW
MIN
-PW
MAX
July 23, 2009
Updated sections Electrical Characteristics on page 6, Timing
Characteristics on page 9 and Detailed Description on page 10
according to AS5145 datasheet.
1.1 Oct 19, 2009
apg
Deleted the following --
1) ‘OTP Programming Connection’ figure
2) Physical Placement of the magnet, Magnet Placement, Simulation
Modeling
1.2 Nov 05, 2009 Timing Characteristics (page 9) - Deleted the parameter ‘PWM
Frequency’ (fPWM)
1.3 Dec 04, 2009 Updated section Internal Timing Tolerance (page 26)
1.4 Apr 01, 2010 Updated standards in Absolute Maximum Ratings on page 5
Apr 13, 2010 Updated Package Drawings and Markings on page 28
1.5 Jun 17, 2010 mub
Updated Mode_Index, PWM, Electrical Characteristics (page 6),
fPWM (page 9), Figure 9, Table 11.
Info on ‘Magnet Input Specification’ deleted from the document.
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AS5245
Data Sheet - Ordering Information
11 Ordering Information
The devices are available as the standard products shown in Table 16.
Note: All products are RoHS compliant and Pb-free.
Buy our products or get free samples online at ICdirect: http://www.austriamicrosystems.com/ICdirect
For further information and requests, please contact us mailto:sales@austriamicrosystems.com
or find your local distributor at http://www.austriamicrosystems.com/distributor
Table 16. Ordering Information
Ordering Code Description Delivery Form Package
AS5245-HMFP, -HMFM 12-bit fully redundant magnetic rotary encoder Tape & Reel QFN 32 (7mm x 7mm)
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AS5245
Data Sheet - Copyrights
Copyrights
Copyright © 1997-2010, austriamicrosystems AG, Tobelbaderstrasse 30, 8141 Unterpremstaetten, Austria-Europe. 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.
All products and companies mentioned are trademarks or registered trademarks of their respective companies.
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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 life-sustaining equipment are
specifically not recommended without additional processing by austriamicrosystems AG for each application. For shipments of less than 100
parts the manufacturing flow might show deviations from the standard production flow, such as test flow or test location.
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