AS5245

AS5245
Programmable 360º Magnetic Angle
Encoder with Absolute SSI and PWM
Output
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.
Ordering Information and Content Guide appear at end of
datasheet.
Key Benefits & Features
The benefits and features of AS5245, Programmable 360º
Magnetic Angle Encoder with Absolute SSI and PWM Output
are listed below:
Figure 1:
Added Value of Using AS5245
Benefits
Features
No mechanical wear
• Contactless high resolution rotational position encoding
over a full turn of 360º
High resolution absolute position sensing
• Two digital 12-bit absolute outputs
Easy to use for motor control
• Quadrature A/B (10- or 12-bit) and Index output signal
Adjustable zero position
• User programmable zero position
Tolerant to magnet misalignment
• Failure detection mode for magnet placement monitoring
and loss of power supply
Usable for high speed applications
• “Red-Yellow-Green” indicators display placement of magnet
in Z-axis
Tolerant to airgap variations
• Tolerant to magnet misalignment and air gap variations
ams Datasheet
[v1-08] 2015-Jun-29
Page 1
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AS5245 − General Description
Benefits
Features
Operates up to 150°C ambient temperature
• Wide temperature range: - 40ºC to 150ºC
Supports daisy chain application
• Unique Chip Identifier
Fitting to automotive applications
• Fully automotive qualified to AEC-Q100, grade 0
Two sensors in one package
• Small package: QFN 32 LD (7x7)
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
• Replacement of potentiometer
Page 2
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ams Datasheet
[v1-08] 2015-Jun-29
AS5245 − General Description
Block Diagram
The functional blocks of this device for reference are
shown below:
Figure 2:
AS5245 Block Diagram
9''9
9''9
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LDO 3.3V
PWM
Interface
6LQ
Hall Array
&
Frontend
Amplifier
Mux
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Absolute
Interface
(SSI)
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AS5245
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Incremental
Interface
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Note(s) and/or Footnote(s):
1. This block diagram presents only one die
ams Datasheet
[v1-08] 2015-Jun-29
Page 3
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AS5245 − Pin Assignments
Pin Assignments
VDD3V_Top
VDDA5V_Bottom
VDDA5V_Top
MagINCn_Top
MagINCn_Bottom
MagDECn_Top
MagDECn_Bottom
DTest1_A_Top
Figure 3:
Pin Assignments (Top View)
32 31 30 29 28 27 26 25
DTest1_A_Bottom
1
24
VDD3V_Bottom
DTest2_B_Top
2
23
NC
DTest2_B_Bottom
3
22
NC
NC
4
21
NC
NC
5
20
NC
Mode_Index_Top
6
19
PWM_Top
Mode_Index_Bottom
7
18
PWM_Bottom
VSS_Top
8
17
CSn_Top
Page 4
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CSn_Bottom
DO_Bottom
DO_Top
CLK_Bottom
PDIO_Top
CLK_Top
10 11 12 13 14 15 16
PDIO_Bottom
9
VSS_Bottom
AS5245
ams Datasheet
[v1-08] 2015-Jun-29
AS5245 − Pin Assignments
Figure 4:
Pin Descriptions
Pin Name
Pin
Number
Pin Type
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
-
Mode_Index
6, 7
Digital I/O pull-down
VSS
8, 9
Supply pin
PDIO
10, 11
Digital input
pull-down
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
PWM
18, 19
Digital output
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.
ams Datasheet
[v1-08] 2015-Jun-29
Description
For internal use. Must be left unconnected
Select between slow (open, low: VSS) and fast (high)
mode. Internal pull-down resistor. Hard wired
connection to VDD or GND recommended.
Negative Supply Voltage (GND)
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.
Chip Select. Active low. Schmitt-Trigger input, internal
pull-up resistor (50kΩ)
Pulse Width Modulation
Page 5
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AS5245 − Absolute Maximum Ratings
Stresses beyond those listed in Absolute Maximum Ratings 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 is not implied. Exposure to absolute maximum
rating conditions for extended periods may affect device
reliability.
Absolute Maximum Ratings
Figure 5:
Absolute Maximum Ratings
Parameter
Min
Max
Units
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
Input current (latchup immunity)
-100
100
mA
Norm: EIA/JESD78 Class II Level A
kV
Norm: JESD22-A114E
Electrostatic discharge
Storage temperature
±2
-55
150
ºC
260
ºC
5
85
%
-40
150
ºC
Body temperature
(Lead-free package)
Humidity non-condensing
Ambient temperature
Moisture sensitivity level
Page 6
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3
Comments
Pins Prog, MagINCn, MagDECn, CLK, CSn
t=20 to 40s, Norm: IPC/JEDEC J-Std-020C
Lead finish 100% Sn “matte tin”
Represents a maximum floor time of 168h
ams Datasheet
[v1-08] 2015-Jun-29
AS5245 − Electrical Characteristics
TAMB = -40 to 150ºC, V DD5V = 3.0-3.6V (3V operation)
VDD5V = 4.5-5.5V (5V operation) unless otherwise noted.
Electrical Characteristics
Figure 6:
Electrical Characteristics
Symbol
Parameter
Condition
Min
Typ
Max
Unit
150
ºC
16
21
mA
5.0
5.5
Operating Conditions
TAMB
Ambient temperature
Isupp
Supply current
VDD5V
Supply voltage at pin
VDD5V
VDD3V3
Voltage regulator output
voltage at pin VDD3V3
VDD5V
Supply voltage at pin
VDD5V
VDD3V3
Supply voltage at pin
VDD3V3
VON
Power-ON reset thresholds
ON voltage; 300mV typ.
hysteresis
-40
(one die only)
4.5
5V Operation
VOFF
V
3.0
3.3
3.6
3.0
3.3
3.6
3.3V Operation (pin VDD5V
and VDD3V3 connected)
Power-ON reset thresholds
OFF voltage; 300mV typ.
hysteresis
V
3.0
3.3
3.6
1.37
2.2
2.9
DC supply voltage 3.3V
(VDD3V3)
V
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
[email protected]
100k
∞
Ω
Runprogrammed
Unprogrammed fuse
resistance (log 0)
2mA maximum
[email protected]
50
100
Ω
ams Datasheet
[v1-08] 2015-Jun-29
Page 7
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AS5245 − Electrical Characteristics
Symbol
Parameter
Condition
Min
Typ
Max
Unit
DC Characteristics CMOS Schmitt-Trigger Inputs: CLK, CSn (CSn = Internal Pull-Up)
0.7 *
VDD5V
VIH
High level input voltage
VIL
Low level input voltage
VIon-VIoff
Schmitt Trigger hysteresis
ILEAK
Input leakage current
CLK only
-1
1
IIL
Pull-up low level input
current
CSn only, VDD5V: 5.0V
-30
-100
Normal operation
V
0.3 *
VDD5V
1
V
V
μA
DC Characteristics CMOS / Program Input: PDIO
VIH
High level input voltage
VPROG
High level input voltage
VIL
Low level input voltage
IIL
Low level input current
During programming,
Either with 3.3V or 5V
supply
VDD5V: 5.5V
0.7 *
VDD5V
VDD5V
V
3.3
3.6
V
0.3 *
VDD5V
V
100
μA
30
DC Characteristics CMOS Output Open Drain: MagINCn, MagDECn
IOZ
Open drain leakage
current
1
μA
VOL
Low level output voltage
VSS
+0.4
V
IO
Output current
VDD5V: 4.5V
4
VDD5V: 3V
2
mA
DC Characteristics CMOS Output: PWM
VOH
High level output voltage
VOL
Low level output voltage
IO
Output current
Page 8
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VDD5V
– 0.5
V
VSS
+0.4
VDD5V: 4.5V
4
VDD5V: 3V
2
V
mA
ams Datasheet
[v1-08] 2015-Jun-29
AS5245 − Electrical Characteristics
Symbol
Parameter
Condition
Min
Typ
Max
Unit
DC Characteristics CMOS Output: A, B, Index
VOH
High level output voltage
VOL
Low level output voltage
IO
Output current
VDD5V
– 0.5
V
VSS
+0.4
VDD5V: 4.5V
4
VDD5V: 3V
2
V
mA
DC Characteristics Tri-State CMOS Output: DO
VOH
High level output voltage
VOL
Low level output voltage
IO
Output current
IOZ
ams Datasheet
[v1-08] 2015-Jun-29
Tri-state leakage current
VDD5V
– 0.5
V
VSS
+0.4
VDD5V: 4.5V
4
VDD5V: 3V
2
V
mA
1
μA
Page 9
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AS5245 − Electrical Characteristics
System Specifications
TAMB = -40 to 150ºC, V DD5V = 3.0 to 3.6V (3V operation)
V DD5V = 4.5 to 5.5V (5V operation) unless otherwise noted.
Figure 7:
Input Specification
Symbol
Parameter
Condition
RES
Resolution
INLopt
INLtemp
Min
Typ
Max
Unit
0.088 deg
12
bit
Integral non-linearity
(optimum)
Maximum error with respect to the
best line fit. Centered magnet
without calibration, TAMB =25ºC.
±0.5
deg
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
±0.044
deg
12bit, no missing codes
1 sigma, fast mode (MODE = 1)
TN
Transition noise
0.06
1 sigma, slow mode (MODE = 0 or
open)
0.03
Fast mode (Mode = 1);
Until status bit OCF = 1
tPwrUp
tdelay
fS
fS
CLK/SEL
20
Power-up time
System propagation
delay absolute output :
delay of ADC, DSP and
absolute interface
Internal sampling rate
for absolute output:
Internal sampling rate
for absolute output
Read-out frequency
Page 10
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Deg
RMS
ms
Slow mode (Mode = 0 or open);
Until OCF = 1
80
Fast mode (MODE = 1)
96
Slow mode (MODE = 0 or open)
384
μs
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
TAMB = 25ºC, fast mode (MODE = 1)
9.90
10.42
10.94
TAMB = -40 to 150ºC, fast mode
(MODE=1)
9.38
10.42
11.46
Maximum clock frequency to read
out serial data
kHz
1
MHz
ams Datasheet
[v1-08] 2015-Jun-29
AS5245 − Electrical Characteristics
Figure 8:
Integral and Differential Non-Linearity Example
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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.
ams Datasheet
[v1-08] 2015-Jun-29
Page 11
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AS5245 − Timing Characteristics
Timing Characteristics
TAMB = -40 to 150ºC, VDD5V = 3.0-3.6V (3V operation)
VDD5V = 4.5-5.5V (5V operation) unless otherwise noted.
Figure 9:
Timing Characteristics
Symbol
Parameter
Conditions
Min
Typ
Max
Units
100
ns
Synchronous Serial Interface (SSI)
tDOactive
Data output activated
(logic high)
Time between falling edge of CSn
and data output activated
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
fCLK
Read-out frequency
Clock frequency to read out serial
data
>0
ns
1
MHz
Pulse Width Modulation Output
Signal period = 4098μs ±10% at
TAMB = -40 to 150ºC
220
244
268
Hz
Minimum pulse width
Position 0d; angle 0 degree
0.90
1
1.10
μs
Maximum pulse width
Position 4098d; angle 359.91
degrees
3686
4096
4506
μs
20
μs
fPWM
PWM frequency
PWMIN
PWMAX
Programming Conditions
tPROG
Programming time per
bit
Time to prog. a singe fuse bit
10
tCHARGE
Refresh time per bit
Time to charge the cap after
tPROG
1
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
Page 12
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μs
ams Datasheet
[v1-08] 2015-Jun-29
AS5245 − Detailed Description
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 30).
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 10:
Typical Arrangement of AS5245 and Magnet
ams Datasheet
[v1-08] 2015-Jun-29
Page 13
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AS5245 − Detailed Description
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:
Figure 11:
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
Note(s) and/or Footnote(s):
1. A change of the Mode during operation is not allowed. The setup must be constant during power up and during operation.
Page 14
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ams Datasheet
[v1-08] 2015-Jun-29
AS5245 − Detailed Description
Synchronous Serial Interface (SSI)
Figure 12:
Synchronous Serial Interface with Absolute Angular Position Data
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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.
ams Datasheet
[v1-08] 2015-Jun-29
Page 15
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AS5245 − Detailed Description
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:
Figure 13:
Status Bit Outputs
OCF
1
COF
0
LIN
Mag INC
Mag DEC
0
0
0
1
1
0
1
1
0
Parity
Even checksum of bits 1:15
Note(s) and/or Footnote(s):
1. MagInc=MagDec=1 is only recommended in YELLOW mode (see Figure 14)
Page 16
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ams Datasheet
[v1-08] 2015-Jun-29
AS5245 − Detailed Description
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 12). 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:
Figure 14:
Magnetic Field Strength Red-Yellow-Green Indicator (OTP Option)
Hardware
Pins
Status Bits
OTP: MagCompEn = 1
(Red-Yellow-Green Programming Option)
Mag
INC
Mag
DEC
LIN
Mag
INCn
Mag
DECn
0
0
0
OFF
OFF
No distance change
Magnetic input field OK (GREEN range, ~45…75mT)
1
1
0
ON
OFF
YELLOW range: magnetic field is ~ 25…45mT or
~75…135mT. The AS5245 may still be operated in this
range, but with slightly reduced accuracy.
1
1
1
ON
ON
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
Description
Note(s) and/or Footnote(s):
1. 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 Figure 14).
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 ams.
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.
ams Datasheet
[v1-08] 2015-Jun-29
Page 17
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AS5245 − Detailed Description
0
0
0
1
10 bit Incremental
mode (low DNL)
12 bit Incremental
mode (high DNL)
Sync mode
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.
In this mode a control signal is
switched to DTEST1_A and
DTEST2_B.
10
256
Index Width
Output Md0
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).
DTest1_A &
DTest2_B
Pulses
Description
Resolution
Mode
Output Md1
Figure 15:
Incremental Resolution
1/3
LSB
1
0
1
1
12
1024
Figure 16:
Incremental Output
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The hysteresis trimming is done at the final test (factory
trimming) and set to 4 LSB, related to a 12 bit number.
Page 18
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ams Datasheet
[v1-08] 2015-Jun-29
AS5245 − Detailed Description
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 17). 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 17:
Hysteresis Window for Incremental Outputs
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ams Datasheet
[v1-08] 2015-Jun-29
Page 19
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AS5245 − 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.
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 18:
DTest1_A and DTest2_B
—V—V
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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.
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.
Page 20
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ams Datasheet
[v1-08] 2015-Jun-29
AS5245 − Detailed Description
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 19). 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 20).
Figure 19:
Daisy Chain Hardware Configuration
AS5245
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ams Datasheet
[v1-08] 2015-Jun-29
Page 21
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AS5245 − Detailed Description
Figure 20:
Daisy Chain Mode Data Transfer
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Page 22
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ams Datasheet
[v1-08] 2015-Jun-29
AS5245 − Detailed Description
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:
(EQ1)
t ON × 4098
Position = ------------------------------- – 1
( t ON + t OFF )
Examples:
1. An angle position of 180º will generate a pulse width
t ON = 2049μs and a pause tOFF of 2049μs 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
t ON = 4095μs and a pause tOFF of 3 μs resulting in
Position = 4094 after the calculation:
4095 * 4098 / (4095 + 3) -1 = 4094
Exception:
1. An angle position of 359.9º will generate a pulse width
t ON = 4097μs and a pause t OFF of 1μs resulting in Position
= 4096 after the calculation:
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 21:
PWM Output Signal
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ams Datasheet
[v1-08] 2015-Jun-29
Page 23
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AS5245 − Detailed Description
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). With PWMhalfEN = 0, the PWM timing is as shown
in Figure 22:
Figure 22:
PWM Signal Parameters (Default mode)
Symbol
Parameter
Typ
Unit
Note
fPWM
PWM frequency
244
Hz
PWMIN
MIN pulse width
1
μs
• Position 0d
• Angle 0 deg
PWMAX
MAX pulse width
4096
μs
• Position 4095d
• Angle 359,91 deg
Signal period: 4097 μs
When PWMhalfEN = 1, the PWM timing is as shown in Figure 23:
Figure 23:
PWM Signal Parameters with Half Frequency (OTP option)
Symbol
Parameter
Typ
Unit
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
Page 24
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Note
ams Datasheet
[v1-08] 2015-Jun-29
AS5245 − Detailed Description
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 24:
Simple 2nd Order Passive RC Low Pass Filter
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to generate the analog output.
(EQ2)
R1, R2 ≥ 4.7kΩ
C1, C2 ≥ 1μF ⁄ 6V
R1 should be greater than or equal to 4.7kΩ 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.
ams Datasheet
[v1-08] 2015-Jun-29
Page 25
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AS5245 − Application Information
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
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 23 bits are available for
user programming. The remaining 29 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.
Page 26
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ams Datasheet
[v1-08] 2015-Jun-29
AS5245 − Application Information
• 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.
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(s): 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.
ams Datasheet
[v1-08] 2015-Jun-29
Page 27
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AS5245 − Application Information
OTP Memory Assignment
Symbol
Function
mbit1
Factory Bit 1
51
PWMhalfEN_Index width
PMW frequency Index pulse
width
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
:
:
35
Z11
34
CCW
33
RA0
:
:
29
RA4
28
FS 0
27
FS 1
26
FS 2
25
FS 3
24
FS 4
23
FS 5
:
:
18
FS11
17
ChipID0
16
ChipID1
:
:
0
ChipID17
12 bit Zero Position
Direction
Factory Bit
18 bit Chip ID
mbit0
Page 28
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Factory Section
Redundancy Address
ID Section
Bit
Customer Section
Figure 25:
OTP Bit Assignment
Factory Bit 0
ams Datasheet
[v1-08] 2015-Jun-29
AS5245 − Application Information
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 Figure 15). It is already set by ams.
• Output Md1: Setting this bit enables sync- or 12bit
incremental mode (see Figure 15)
• 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
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.
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.
ams Datasheet
[v1-08] 2015-Jun-29
Page 29
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A S 5 2 4 5 − Application Information
Figure 26:
Redundancy Addressing
Address
PWMhalfEN
_Indexwidth
Mag
CompEN
pwm
DIS
Output
Md0
Output
Md1
Z0
Z1
Z2
Z3
Z4
Z5
Z6
Z7
Z8
Z9
Z10
Z11
CCW
00000
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
00001
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
00010
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
00011
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
00100
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
00101
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
00110
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
00111
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
01000
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
01001
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
01010
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
01011
01100
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
01101
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
01110
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
01111
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
10000
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
Page 30
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ams Datasheet
[v1-08] 2015-Jun-29
A S 5 2 4 5 − Application Information
Address
PWMhalfEN
_Indexwidth
Mag
CompEN
pwm
DIS
Output
Md0
Output
Md1
Z0
Z1
Z2
Z3
Z4
Z5
Z6
Z7
Z8
Z9
Z10
Z11
CCW
10001
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
10010
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
10101
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
ams Datasheet
[v1-08] 2015-Jun-29
Page 31
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AS5245 − Application Information
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.
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 27). 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.
Page 32
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ams Datasheet
[v1-08] 2015-Jun-29
AS5245 − Application Information
Figure 27:
Enabling the Alignment Mode
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ams Datasheet
[v1-08] 2015-Jun-29
H[LW$OLJQ0RGH
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Page 33
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AS5245 − Application Information
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 29).
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 29).
Note(s): 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 29:
Connections for 5V / 3.3V Supply Voltages
5V Operation
3.3V Operation
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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.
Page 34
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ams Datasheet
[v1-08] 2015-Jun-29
AS5245 − Application Information
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 B v 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 30).
Figure 30:
Typical Magnet (6x3mm) and Magnetic Field Distribution
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ams Datasheet
[v1-08] 2015-Jun-29
Page 35
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AS5245 − Application Information
Failure Diagnostics
The AS5245 also offers several diagnostic and failure detection
features, which are discussed in detail further in the document.
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).
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 Figure 14). 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.
Page 36
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ams Datasheet
[v1-08] 2015-Jun-29
AS5245 − Application Information
Angular Output Tolerances
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
= (Err max - Err min )/2 is specified as better than ±0.5 degrees
@ 25ºC (see Figure 34).
Misalignment of the magnet further reduces the accuracy.
Figure 32 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 34 is repeated and the accuracy (Errmax - Err min)/2 (e.g.
0.25º in Figure 34) is entered as the Z-axis in the 3D-graph.
ams Datasheet
[v1-08] 2015-Jun-29
Page 37
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AS5245 − Application Information
Figure 31:
Example of Linearity Error Over XY Misalignment
6
5
4
° 3
800
500
2
200
1
-100
x
-1000
-1000
-800
-600
-400
-200
y
-700
0
200
-400
400
800
600
1000
0
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.
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ams Datasheet
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AS5245 − Application Information
Figure 32:
Example of Linearity Error Over 360º
0.5
0.4
0.3
0.2
transition noise
0.1
Err max
0
-0.1
1
55
109
163
217
271
325
379
433
487
541
595
649
703
757
811
865
919
973
Err min
-0.2
-0.3
-0.4
-0.5
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 lowering 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).
1. Statistically, 1 sigma represents 68.27% of readings; 3 sigma represents 99.73% of readings.
ams Datasheet
[v1-08] 2015-Jun-29
Page 39
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AS5245 − Application Information
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,
(EQ3)
60
n slowmode = -------------------------------rpm × 384μs
(EQ4)
60
n fastmode = ----------------------------rpm × 96μs
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 Figure 11). Regardless of the rotational speed,
the absolute angular value is always sampled at the highest
resolution of 12 bit.
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).
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AS5245 − Application Information
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:
(EQ5)
e sampling = rpm • 6 • prop ⋅ delay
Where:
esampling = angular error [º]
rpm = rotating speed [rpm]
prop.delay = propagation delay [seconds]
Note(s): Since the propagation delay is known, it can be
automatically compensated by the control unit processing the
data from the AS5245.
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 t ON and t OFF 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
t OFF and calculating the angle from the duty cycle
(see Pulse Width Modulation (PWM) Output).
• 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).
(EQ6)
ams Datasheet
[v1-08] 2015-Jun-29
t ON × 4097
Position = ------------------------------- – 1
( t ON + t OFF )
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AS5245 − Application Information
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.
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.
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.
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AS5245 − Application Information
AS5245 Differences to AS5045
All parameters are according to AS5045 data sheet except for
the parameters shown below:
Figure 33:
Difference Between AS5245 and AS5045
Building Block
Resolution
AS5245
AS5045
12bits, 0.088º/step.
12bits, 0.088º/step.
-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
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
384μs (slow mode)
384μs (slow mode)
96μs (fast mode)
96μs (fast mode)
0.03 degrees maximum (slow mode)
0.03 degrees maximum (slow mode)
0.06 degrees maximum (fast mode)
0.06 degrees maximum (fast mode)
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;
Ambient temperature
range
Incremental encoder
Propagation delay
Transition noise
(rms; 1sigma)
OTP programming
options
ams Datasheet
[v1-08] 2015-Jun-29
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AS5245 − Package Drawings & Mark ings
Package Drawings & Markings
The device is available in a QFN 32 (7mm x 7mm) package.
Figure 34:
Package Drawing
YYWWVZZ @
AS5245
17771-102
RoHS
Green
Symbol
Min
Typ
Max
Symbol
A
A1
A2
A3
L
Θ
b
D
E
e
0.80
0
-
0.90
0.02
0.65
0.20 REF
0.60
0.28
7.00 BSC
7.00 BSC
0.65 BSC
1.00
0.05
1.00
D1
E1
D2
E2
aaa
bbb
ccc
ddd
eee
fff
N
0.50
0º
0.23
0.75
14º
0.35
Min
4.70
4.70
-
Typ
6.75 BSC
6.75 BSC
4.80
4.80
0.15
0.10
0.10
0.05
0.08
0.10
32
Max
4.90
4.90
-
Note(s) and/or Footnote(s):
1. Dimensions and tolerancing conform to ASME Y14.5M-1994.
2. All dimensions are in millimeters (angles in degrees).
3. Bilateral coplanarity zone applies to the exposed pad as well as the terminal.
4. Radius on terminal is optional.
5. N is the total number of terminals.
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ams Datasheet
[v1-08] 2015-Jun-29
AS5245 − Package Drawings & Markings
Figure 35:
Package Code: @YYWWVZZ
YY
WW
V
ZZ
@
Last two digits of
the year
Manufacturing week
Plant identifier
Assembly
traceability code
Sublot identifier
ams Datasheet
[v1-08] 2015-Jun-29
Page 45
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AS5245 − Ordering & Contact Information
Ordering & Contact Information
Figure 36:
Ordering Information
Ordering Code
Package
Marking
Delivery Form
QFN 32 (7mm x 7mm)
AS5245
Tape & Reel
Delivery Quantity
AS5245-HMFP
4000
AS5245-HMFM
500
Buy our products or get free samples online at:
www.ams.com/ICdirect
Technical Support is available at:
www.ams.com/Technical-Support
Provide feedback about this document at:
www.ams.com/Document-Feedback
For further information and requests, e-mail us at:
[email protected]
For sales offices, distributors and representatives, please visit:
www.ams.com/contact
Headquarters
ams AG
Tobelbaderstrasse 30
8141 Unterpremstaetten
Austria, Europe
Tel: +43 (0) 3136 500 0
Website: www.ams.com
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AS5245 − RoHS Compliant & ams Green Statement
RoHS Compliant & ams Green
Statement
RoHS: The term RoHS compliant means that ams AG products
fully comply with current RoHS directives. Our semiconductor
products do not contain any chemicals for all 6 substance
categories, including the requirement that lead not exceed
0.1% by weight in homogeneous materials. Where designed to
be soldered at high temperatures, RoHS compliant products are
suitable for use in specified lead-free processes.
ams Green (RoHS compliant and no Sb/Br): ams Green
defines that in addition to RoHS compliance, our products are
free of Bromine (Br) and Antimony (Sb) based flame retardants
(Br or Sb do not exceed 0.1% by weight in homogeneous
material).
Important Information: The information provided in this
statement represents ams AG knowledge and belief as of the
date that it is provided. ams AG bases its knowledge and belief
on information provided by third parties, and makes no
representation or warranty as to the accuracy of such
information. Efforts are underway to better integrate
information from third parties. ams AG has taken and continues
to take reasonable steps to provide representative and accurate
information but may not have conducted destructive testing or
chemical analysis on incoming materials and chemicals. ams AG
and ams AG suppliers consider certain information to be
proprietary, and thus CAS numbers and other limited
information may not be available for release.
ams Datasheet
[v1-08] 2015-Jun-29
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AS5245 − Copyrights & Disclaimer
Copyrights & Disclaimer
Copyright ams AG, Tobelbader Strasse 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.
Devices sold by ams AG are covered by the warranty and patent
indemnification provisions appearing in its General Terms of
Trade. ams AG makes no warranty, express, statutory, implied,
or by description regarding the information set forth herein.
ams 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 ams AG
for current information. This product is intended for use in
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 ams AG for
each application. This product is provided by ams AG “AS IS”
and any express or implied warranties, including, but not
limited to the implied warranties of merchantability and fitness
for a particular purpose are disclaimed.
ams 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 ams AG rendering of technical or other services.
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AS5245 − Document Status
Document Status
Document Status
Product Preview
Preliminary Datasheet
Datasheet
Datasheet (discontinued)
ams Datasheet
[v1-08] 2015-Jun-29
Product Status
Definition
Pre-Development
Information in this datasheet is based on product ideas in
the planning phase of development. All specifications are
design goals without any warranty and are subject to
change without notice
Pre-Production
Information in this datasheet is based on products in the
design, validation or qualification phase of development.
The performance and parameters shown in this document
are preliminary without any warranty and are subject to
change without notice
Production
Information in this datasheet is based on products in
ramp-up to full production or full production which
conform to specifications in accordance with the terms of
ams AG standard warranty as given in the General Terms of
Trade
Discontinued
Information in this datasheet is based on products which
conform to specifications in accordance with the terms of
ams AG standard warranty as given in the General Terms of
Trade, but these products have been superseded and
should not be used for new designs
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AS5245 − Revision Information
Revision Information
Changes from 1.5 (2010-Jun-17) to current revision 1-08 (2015-Jun-29)
Page
1.5 (2010-Jun-17) to 1-06 (2015-May-20)
Content of austriamicrosystems datasheet was converted to latest ams design
Added benefits to Figure 1
1
Updated Figure 10
13
Updated text under Programming the AS5245
26
Updated Figure 25
28
1-06 (2015-May-20) to 1-07 (2015-Jun-25)
Updated Figure 5
6
Updated Package Drawings & Markings section
44
1-07 (2015-Jun-25) to 1-08 (2015-Jun-29)
Updated Package Drawings & Markings section
44
Note(s) and/or Footnote(s):
1. Page and figure numbers for the previous version may differ from page and figure numbers in the current revision.
2. Correction of typographical errors is not explicitly mentioned.
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AS5245 − Content Guide
Content Guide
ams Datasheet
[v1-08] 2015-Jun-29
1
1
2
3
General Description
Key Benefits & Features
Applications
Block Diagram
4
6
Pin Assignments
Absolute Maximum Ratings
7
10
Electrical Characteristics
System Specifications
12
Timing Characteristics
13
14
15
16
17
17
19
20
20
20
21
23
24
25
Detailed Description
Mode_Index Pin
Synchronous Serial Interface (SSI)
Serial Data Contents
Z-Axis Range Indication (Push Button Feature, Red/Yellow/Green Indicator)
Incremental Mode
Incremental Output Hysteresis.
Incremental Output Validity.
Sync Mode
Sine/Cosine Mode
Daisy Chain Mode
Pulse Width Modulation (PWM) Output
Changing the PWM Frequency
Analog Output
26
26
27
28
29
29
29
32
32
34
35
36
36
36
37
37
39
40
41
41
42
42
43
Application Information
Programming the AS5245
Zero Position Programming
OTP Memory Assignment
User Selectable Settings
OTP Default Setting
Redundancy
Redundant Programming Option
Alignment Mode
3.3V / 5V Operation
Choosing the Proper Magnet
Failure Diagnostics
Magnetic Field Strength Diagnosis
Power Supply Failure Detection
Angular Output Tolerances
Accuracy
Transition Noise
High Speed Operation
Propagation Delays
Internal Timing Tolerance
Temperature
Accuracy over Temperature
AS5245 Differences to AS5045
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AS5245 − Content Guide
44
46
47
48
49
50
Page 52
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Package Drawings & Markings
Ordering & Contact Information
RoHS Compliant & ams Green Statement
Copyrights & Disclaimer
Document Status
Revision Information
ams Datasheet
[v1-08] 2015-Jun-29