ams Datasheet Page 1
[v1-08] 2015-Jun-29 Document Feedback
AS5245
Programmable 360º Magnetic Angle
Encoder with Absolute SSI and PWM
Output
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
General Description
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AS5245 − General Description
Applications
The AS5245 is ideal for applications with an angular travel range
f ro m a fe w d e gr ee s u p t o a fu l l t u r n o f 3 60 º . T h e d e v ic e i s s ui t ab l e
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
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)
Benefits Features
ams Datasheet Page 3
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AS5245 − General Description
Block Diagram
The functional blocks of this device for reference are
shown below:
Figure 2:
AS5245 Block Diagram
Note(s) and/or Footnote(s):
1. This block diagram presents only one die
DSP
Hall Array
&
Frontend
Amplifier
Absolute
Interface
(SSI)
Incremental
Interface
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Page 4 ams Datasheet
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AS5245 − Pin Assignments
Figure 3:
Pin Assignments (Top View)
Pin Assignments
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
ams Datasheet Page 5
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AS5245 − Pin Assignments
Figure 4:
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.
Page 6 ams Datasheet
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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.
Figure 5:
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
Moisture sensitivity level 3 Represents a maximum floor time of 168h
Absolute Maximum Ratings
ams Datasheet Page 7
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AS5245 − Electrical Characteristics
TAMB = -40 to 150ºC, VDD5V = 3.0-3.6V (3V operation)
VDD5V = 4.5-5.5V (5V operation) unless otherwise noted.
Figure 6:
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
Electrical Characteristics
Page 8 ams Datasheet
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AS5245 − Electrical Characteristics
DC Characteristics CMOS Schmitt-Trigger 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 Low 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
IO Output 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
IO Output current
VDD5V: 4.5V 4
mA
VDD5V: 3V 2
Symbol Parameter Condition Min Typ Max Unit
ams Datasheet Page 9
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AS5245 − Electrical Characteristics
DC Characteristics CMOS Output: A, B, Index
VOH High level output voltage VDD5V
– 0.5 V
VOL Low level output voltage VSS
+0.4 V
IO Output 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
IO Output current
VDD5V: 4.5V 4
mA
VDD5V: 3V 2
IOZ Tri-state leakage current 1 μA
Symbol Parameter Condition Min Typ Max Unit
Page 10 ams Datasheet
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AS5245 − Electrical Characteristics
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.
Figure 7:
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
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
fS Internal 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
fS Internal 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 1 MHz
ams Datasheet Page 11
[v1-08] 2015-Jun-29 Document Feedback
AS5245 − Electrical Characteristics
Figure 8:
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.
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Page 12 ams Datasheet
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AS5245 − Timi ng 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
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 1 μs
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
Timing Characteristics
ams Datasheet Page 13
[v1-08] 2015-Jun-29 Document Feedback
AS5245 − 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
Detailed Description
Page 14 ams Datasheet
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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
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.
Parameter Slow Mode (mode=low or open) Fast Mode (mode=high, VDD=5V)
Sampling rate 2.61 kHz (384 s) 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
ams Datasheet Page 15
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AS5245 − Detailed Description
Synchronous Serial Interface (SSI)
Figure 12:
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.
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Page 16 ams Datasheet
Document Feedback [v1-08] 2015-Jun-29
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
Note(s) and/or Footnote(s):
1. MagInc=MagDec=1 is only recommended in YELLOW mode (see Figure 14)
OCF COF LIN Mag INC Mag DEC Parity
10 0
00
Even checksum of bits 1:15
01
10
11
ams Datasheet Page 17
[v1-08] 2015-Jun-29 Document Feedback
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)
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.
Status Bits Hardware
Pins
OTP: MagCompEn = 1
(Red-Yellow-Green Programming Option)
Mag
INC
Mag
DEC LIN Mag
INCn
Mag
DECn Description
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
Page 18 ams Datasheet
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AS5245 − Detailed Description
Figure 15:
Incremental Resolution
Figure 16:
Incremental Output
The hysteresis trimming is done at the final test (factory
trimming) and set to 4 LSB, related to a 12 bit number.
Mode Description
Output Md1
Output Md0
Resolution
DTest1_A &
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.
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ams Datasheet Page 19
[v1-08] 2015-Jun-29 Document Feedback
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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Page 20 ams Datasheet
Document Feedback [v1-08] 2015-Jun-29
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
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.
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ams Datasheet Page 21
[v1-08] 2015-Jun-29 Document Feedback
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
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Page 22 ams Datasheet
Document Feedback [v1-08] 2015-Jun-29
AS5245 − Detailed Description
Figure 20:
Daisy Chain Mode Data Transfer
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ams Datasheet Page 23
[v1-08] 2015-Jun-29 Document Feedback
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:
Examples:
1. An angle position of 180º will generate a pulse width
tON = 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
tON = 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
tON = 4097μs and a pause tOFF 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
(EQ1)
Position tON 4098×
tON tOFF
+()
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Page 24 ams Datasheet
Document Feedback [v1-08] 2015-Jun-29
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)
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 Note
fPWM PWM frequency 244 Hz Signal period: 4097 μs
PWMIN MIN pulse width 1 μs •Position 0d
•Angle 0 deg
PWMAX MAX pulse width 4096 μs •Position 4095d
•Angle 359,91 deg
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
ams Datasheet Page 25
[v1-08] 2015-Jun-29 Document Feedback
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
Figure 24 shows an example of a simple passive low pass filter
to generate the analog output.
R1 should be greater than or equal to 4.7k 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.
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Page 26 ams Datasheet
Document Feedback [v1-08] 2015-Jun-29
AS5245 − 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.
Application Information
ams Datasheet Page 27
[v1-08] 2015-Jun-29 Document Feedback
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.
Page 28 ams Datasheet
Document Feedback [v1-08] 2015-Jun-29
AS5245 − Application Information
OTP Memory Assignment
Figure 25:
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
: :
18 FS11
17 ChipID0
18 bit Chip ID
ID Section
16 ChipID1
: :
0 ChipID17
mbit0 Factory Bit 0
ams Datasheet Page 29
[v1-08] 2015-Jun-29 Document Feedback
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.
Page 30 ams Datasheet
Document Feedback [v1-08] 2015-Jun-29
AS5245 − 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
ams Datasheet Page 31
[v1-08] 2015-Jun-29 Document Feedback
AS5245 − Application Information
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
Address PWMhalfEN
_Indexwidth
Mag
CompEN
pwm
DIS
Output
Md0
Output
Md1 Z0 Z1 Z2 Z3 Z4 Z5 Z6 Z7 Z8 Z9 Z10 Z11 CCW
Page 32 ams Datasheet
Document Feedback [v1-08] 2015-Jun-29
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 34 ams Datasheet
Document Feedback [v1-08] 2015-Jun-29
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
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.
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ams Datasheet Page 35
[v1-08] 2015-Jun-29 Document Feedback
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 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 30).
Figure 30:
Typical Magnet (6x3mm) and Magnetic Field Distribution
Magnet axis
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Page 36 ams Datasheet
Document Feedback [v1-08] 2015-Jun-29
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.
ams Datasheet Page 37
[v1-08] 2015-Jun-29 Document Feedback
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
= (Errmax - Errmin)/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 - Errmin)/2 (e.g.
0.25º in Figure 34) is entered as the Z-axis in the 3D-graph.
Page 38 ams Datasheet
Document Feedback [v1-08] 2015-Jun-29
AS5245 − Application Information
Figure 31:
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
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-400
-100
200
500
800
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-800
-600
-400
-200
0
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400
600
800
1000
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2
3
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ams Datasheet Page 39
[v1-08] 2015-Jun-29 Document Feedback
AS5245 − Application Information
Figure 32:
Example of Linearity Error Over 360º
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.
-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
Page 40 ams Datasheet
Document Feedback [v1-08] 2015-Jun-29
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,
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).
(EQ3)
nslowmode
60
rpm 384μs×
--------------------------------
=
(EQ4)
nfastmode
60
rpm 96μs×
-----------------------------
=
ams Datasheet Page 41
[v1-08] 2015-Jun-29 Document Feedback
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:
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 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).
• 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).
(EQ5)
esampling rpm 6 prop delay⋅••=
(EQ6)
Position tON 4097×
tON tOFF
+()
-------------------------------1–=
Page 42 ams Datasheet
Document Feedback [v1-08] 2015-Jun-29
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.
ams Datasheet Page 43
[v1-08] 2015-Jun-29 Document Feedback
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 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;
Page 44 ams Datasheet
Document Feedback [v1-08] 2015-Jun-29
AS5245 − Package Drawings & Markings
The device is available in a QFN 32 (7mm x 7mm) package.
Figure 34:
Package Drawing
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.
Package Drawings & Markings
Green
RoHS
YYWWVZZ @
AS5245
17771-102
Symbol Min Typ Max
A 0.80 0.90 1.00
A1 0 0.02 0.05
A2 - 0.65 1.00
A3 0.20 REF
L 0.50 0.60 0.75
Θ0º - 14º
b 0.23 0.28 0.35
D7.00 BSC
E7.00 BSC
e0.65 BSC
Symbol Min Typ Max
D1 6.75 BSC
E1 6.75 BSC
D2 4.70 4.80 4.90
E2 4.70 4.80 4.90
aaa - 0.15 -
bbb - 0.10 -
ccc - 0.10 -
ddd - 0.05 -
eee - 0.08 -
fff - 0.10 -
N32
Page 46 ams Datasheet
Document Feedback [v1-08] 2015-Jun-29
AS5245 − Ordering & Contact Information
Figure 36:
Ordering Information
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:
ams_sales@ams.com
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
Ordering Code Package Marking Delivery Form Delivery Quantity
AS5245-HMFP
QFN 32 (7mm x 7mm) AS5245 Tape & Reel
4000
AS5245-HMFM 500
Ordering & Contact Information
ams Datasheet Page 47
[v1-08] 2015-Jun-29 Document Feedback
AS5245 − 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.
RoHS Compliant & ams Green
Statement
Page 48 ams Datasheet
Document Feedback [v1-08] 2015-Jun-29
AS5245 − Copyright s & 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.
Copyrights & Disclaimer
ams Datasheet Page 49
[v1-08] 2015-Jun-29 Document Feedback
AS5245 − Document Status
Document Status Product Status Definition
Product Preview 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
Preliminary Datasheet 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
Datasheet 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
Datasheet (discontinued) 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
Document Status
Page 50 ams Datasheet
Document Feedback [v1-08] 2015-Jun-29
AS5245 − Revision Information
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.
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
Revision Information
ams Datasheet Page 51
[v1-08] 2015-Jun-29 Document Feedback
AS5245 − Content Guide
1 General Description
1 Key Benefits & Features
2 Applications
3 Block Diagram
4 Pin Assignments
6Absolute Maximum Ratings
7 Electrical Characteristics
10 System Specifications
12 Timing Characteristics
13 Detailed Description
14 Mode_Index Pin
15 Synchronous Serial Interface (SSI)
16 Serial Data Contents
17 Z-Axis Range Indication (Push Button Feature, Red/Yel-
low/Green Indicator)
17 Incremental Mode
19 Incremental Output Hysteresis.
20 Incremental Output Validity.
20 Sync Mode
20 Sine/Cosine Mode
21 Daisy Chain Mode
23 Pulse Width Modulation (PWM) Output
24 Changing the PWM Frequency
25 Analog Output
26 Application Information
26 Programming the AS5245
27 Zero Position Programming
28 OTP Memory Assignment
29 User Selectable Settings
29 OTP Default Setting
29 Redundancy
32 Redundant Programming Option
32 Alignment Mode
34 3.3V / 5V Operation
35 Choosing the Proper Magnet
36 Failure Diagnostics
36 Magnetic Field Strength Diagnosis
36 Power Supply Failure Detection
37 Angular Output Tolerances
37 Accuracy
39 Transition Noise
40 High Speed Operation
41 Propagation Delays
41 Internal Timing Tolerance
42 Temperature
42 Accuracy over Temperature
43 AS5245 Differences to AS5045
Content Guide
