AS5045B
12-Bit Programmable Magnetic
Position Sensor
General Description
The AS5045B is a contactless magnetic position sensor for
accurate angular measurement over a full turn of 360 degrees.
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 can 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 the AS5045B to operate at
either 3.3V or 5V supplies.
Ordering Information and Content Guide appear at end of
datasheet.
Key Benefits & Features
The benefits and features of AS5045B, 12-Bit Programmable
Magnetic Position Sensor are listed below:
Figure 1:
Added Value of Using AS5045B
Benefits
Features
• Highest reliability and durability
• Contactless high resolution rotational position encoding
over a full turn of 360 degrees
• Simple programming
• Simple user-programmable zero position and settings
• Multiple interfaces
• Serial communication interface (SSI)
• 10-bit pulse width modulated (PWM) output
• Quadrature A/B and Index output signal
• Ideal for motor applications
• Rational speeds up to 30,000 rpm
• Failure diagnostics
• Failure detection mode for magnet placement monitoring
and loss of power supply
• Easy setup
• Serial read-out of multiple interconnected AS5045B
devices using Daisy Chain mode
• Great flexibility at a huge application area
• Detects movement of magnet in Z-axis (Red-Yellow-Green
indicator)
• Small form factor
• SSOP 16 (5.3mm x 6.2mm)
• Robust environmental tolerance
• Wide temperature range: -40°C to 125°C
ams Datasheet
[v2-00] 2016-Feb-05
Page 1
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AS5045B − General Description
Applications
The device is ideal for industrial applications like automatic or
elevator doors, robotics, motor control and optical encoder
replacement.
Block Diagram
The functional blocks of this device are shown below:
Figure 2:
Block Diagram Rotary Position Sensor IC
VDD3V3
MagINCn
VDD5V
MagDECn
LDO 3.3V
PWM
Interface
Sin
Hall Array
&
Frontend
Amplifier
Cos
PWM
Ang
ATAN
(Cordic)
Mag
Absolute
Interface
(SSI)
DO
CSn
CLK
OTP
Register
PDIO
A
AS5045B
Incremental
Interface
B
I
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AS5045B − Pin Assignment
Pin Assignment
Figure 3:
Pin Diagram (Top View)
1
16
VDD5V
MagDECn
2
15
VDD3V3
A
3
14
NC
B
4
13
NC
NC
5
12
PWM
I
6
11
CSn
VSS
7
10
CLK
PDIO
8
9
DO
AS5045B
MagINCn
The following SSOP16 shows the description of each pin of the
standard SSOP16 package (Shrink Small Outline Package, 16
leads, body size: 5.3mm x 6.2mmm; see Figure 3.
Figure 4:
Pin Description
Pin Name
Pin
Number
MagINCn
1
Pin Type
Digital output open
drain
MagDECn
2
A
3
Description
Magnet Field Magnitude Increase. Active low.
Indicates a distance reduction between the
magnet and the device surface. (see Figure 14)
Magnet Field Magnitude Decrease. Active low.
Indicates a distance increase between the device
and the magnet. (see Figure 14)
Quadrature output A (1024 Pulses)
Digital output
B
4
NC
5
-
I
6
Digital output
VSS
7
Supply pin
PDIO
8
Digital input
pull-down
DO
9
Digital output/
tri-state
ams Datasheet
[v2-00] 2016-Feb-05
Quadrature output B (1024 Pulses)
Must be left unconnected
Index signal for the quadrature output.
Negative supply voltage (GND)
OTP Programming Input and Data Input for
Daisy Chain Mode. Pin has an internal pull-down
resistor (74kΩ). Connect this pin to VSS if
programming is not required.
Data Output of Synchronous Serial Interface
Page 3
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AS5045B − Pin Assignment
Pin Name
Pin
Number
Pin Type
CLK
10
Digital input,
Schmitt-Trigger input
Clock Input of Synchronous Serial Interface;
Schmitt-Trigger input
CSn
11
Digital input
pull-down,
Schmitt-Trigger input
Chip Select. Active low. Schmitt-Trigger input,
internal pull-up resistor (50kΩ)
PWM
12
Digital output
NC
13
-
Must be left unconnected
NC
14
-
Must be left unconnected
VDD3V3
15
Supply pin
3V-Regulator output, internally regulated from
VDD5V. Connect to VDD5V for 3V supply voltage.
Do not load externally.
VDD5V
16
Supply pin
Positive supply voltage, 3.0V to 5.5V
Description
Pulse Width Modulation
Pin 1 and 2 are the magnetic field change indicators, MagINCn
and MagDECn (magnetic field strength increase or decrease
through variation of the distance between the magnet and the
device). These outputs can be used to detect the valid magnetic
field range. Furthermore those indicators can also be used for
contactless push-button functionality.
Pin 3 and 4 are used for incremental angle information in 12-bit
quadrature signal format. Additional sync mode and
sine/cosine mode are used with Pin3 and Pin4.
Pin 6 Index output used for incremental angle information.
(Zero position reference).
Pins 7, 15, and 16 are supply pins, pins 5, 13, and 14 are for
internal use and must not be connected.
Pin 8 (PDIO) is used to program the zero-position into the OTP
(see page 26). This pin is also used as digital input to shift serial
data through the device in daisy chain configuration, (see page
17).
Pin 11 Chip Select (CSn; active low) selects a device within a
network of AS5045Bs and initiates serial data transfer. A logic
high at CSn puts the data output pin (DO) to tri-state and
terminates serial data transfer. This pin is also used for
alignment mode (see Alignment Mode) and programming
mode (see Programming the AS5045B).
Pin 12 allows a single wire output of the 12-bit absolute position
value. The value is encoded into a pulse width modulated signal
with 1μs pulse width per step (1μs to 4096μs over a full turn).
By using an external low pass filter, the digital PWM signal is
converted into an analog voltage, e.g. for making a direct
replacement of potentiometers possible.
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[v2-00] 2016-Feb-05
AS5045B − Absolute Maximum Ratings
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
Electrical Parameters
DC supply voltage at pin VDD5V
-0.3
DC supply voltage at pin
VDD3V3
7
V
5
V
Input pin voltage
-0.3
VDD5V
+0.3
V
Input current (latchup immunity)
-100
100
mA
Except VDD3V3
EIA/JESD78 Class II Level A
Electrostatic Discharge
Electrostatic discharge
±2
kV
JESD22-A114E
Temperature Ranges and Storage Conditions
Storage temperature
-55
150
Package body temperature
Relative humidity
non-condensing
Moisture sensitivity level (MSL)
ams Datasheet
[v2-00] 2016-Feb-05
5
3
ºC
Min -67ºF; Max 302ºF
260
ºC
The reflow peak soldering temperature
(body temperature) specified is in
accordance with IPC/JEDEC J-STD-020
“Moisture/Reflow Sensitivity Classification
for Non-Hermetic Solid State Surface Mount
Devices”.
The lead finish for Pb-free leaded
packages is matte tin (100% Sn).
85
%
Represents a maximum floor time of 168h
Page 5
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AS5045B − Electrical Characteristics
Electrical Characteristics
TAMB = -40°C to 125°C, VDD5V = 3.0V to 3.6V (3V operation)
VDD5V = 4.5V to 5.5V (5V operation), unless otherwise noted.
Figure 6:
Electrical Characteristics
Symbol
Parameter
Condition
Min
Typ
Max
Units
125
°C
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
Voff
Power-on reset
thresholds Off voltage;
300mV typ. hysteresis
-40°F to 257°F
-40
4.5
5V operation
3.3V operation
(pin VDD5V and VDD3V3
connected)
V
3.0
3.3
3.6
3.0
3.3
3.6
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
Programmed fuse
resistance (log 1)
10μA max. current @
100mV
10k
∞
Ω
Unprogrammed fuse
resistance (log 0)
2mA max. current @
100mV
50
100
Ω
Rprogrammed
Runprogrammed
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[v2-00] 2016-Feb-05
AS5045B − Electrical Characteristics
Symbol
Parameter
Condition
Min
Typ
Max
Units
DC Characteristics CMOS Schmitt-Trigger Inputs: CLK, CSn (CSn = Internal Pull-Up)
VIH
High level input voltage
VIL
Low level input voltage
VIon- VIoff
Normal operation
0.7 *
VDD5V
V
0.3 *
VDD5V
Schmitt trigger
hysteresis
1
V
V
ILEAK
Input leakage current
CLK only
-1
1
IiL
Pull-up low level input
current
CSn only, VDD5V: 5.0V
-30
-100
μA
DC Characteristics CMOS / Program Input: PDIO
VIH
High level input voltage
VPROG(1)
High level input voltage
VIL
Low level input voltage
IIH
High level input current
During programming
VDD5V: 5.5V
0.7 *
VDD5V
VDD5V
V
3.3
3.6
V
0.3 *
VDD5V
V
100
μA
1
μA
VSS +
0.4
V
30
DC Characteristics CMOS Output Open Drain: MagINCn, MagDECn
IOZ
Open drain leakage
current
VOL
Low level output voltage
IO
VDD5V: 4.5V
4
VDD5V: 3V
2
Output current
mA
DC Characteristics CMOS Output: PWM
VOH
High level output
voltage
VOL
Low level output voltage
IO
ams Datasheet
[v2-00] 2016-Feb-05
VDD5V
– 0.5
V
VSS
+0.4
VDD5V: 4.5V
4
VDD5V: 3V
2
Output current
V
mA
Page 7
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AS5045B − Electrical Characteristics
Symbol
Parameter
Condition
Min
Typ
Max
Units
DC Characteristics CMOS Output: A, B, Index
VOH
High level output
voltage
VOL
Low level output voltage
IO
VDD5V
– 0.5
V
VSS
+0.4
VDD5V: 4.5V
4
VDD5V: 3V
2
Output current
V
mA
DC Characteristics Tri-state CMOS Output: DO
VOH
High level output
voltage
VOL
Low level output voltage
IO
IOZ
VDD5V
– 0.5
V
VSS
+0.4
VDD5V: 4.5V
4
VDD5V: 3V
2
Output current
Tri-state leakage current
V
mA
1
μA
Note(s):
1. Either with 3.3V or 5V supply.
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[v2-00] 2016-Feb-05
AS5045B − Electrical Characteristics
Magnetic Input Specification
TAMB = -40°C to 125°C, VDD5V = 3.0V to 3.6V (3V operation)
VDD5V = 4.5V to 5.5V (5V operation) unless otherwise noted.
Two-pole cylindrical diametrically magnetized source:
Figure 7:
Magnetic Input Specification
Symbol
Parameter
dmag
Diameter
tmag
Thickness
Condition
Recommended magnet: Ø 6mm
x 2.5mm for cylindrical magnets
Bpk
Magnetic input field
amplitude
Required vertical component of
the magnetic field strength on
the die’s surface, measured along
a concentric circle with a radius
of 1.1mm
Boff
Magnetic offset
fmag_abs
Min
Typ
4
6
Max
Unit
mm
2.5
mm
75
mT
Constant magnetic stray field
± 10
mT
Input frequency
(rotational speed of
magnet)
153 rpm @ 4096 positions/rev
2.54
Hz
Disp
Displacement radius
Max. offset between defined
device center and magnet axis
(see Figure 32)
0.25
mm
Ecc
Eccentricity
Eccentricity of magnet center to
rotational axis
100
μm
Recommended magnet
material and
temperature drift
ams Datasheet
[v2-00] 2016-Feb-05
45
NdFeB (Neodymium Iron Boron)
-0.12
SmCo (Samarium Cobalt)
-0.035
%/K
Page 9
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AS5045B − Electrical Characteristics
System Specifications
TAMB = -40°C to 125°C, VDD5V = 3.0V to 3.6V (3V operation)
VDD5V = 4.5V to 5.5V (5V operation) unless otherwise noted.
Figure 8:
Input Specification
Symbol
RES
Parameter
Condition
Min
Typ
Max
Unit
12
bit
Resolution
0.088 deg
Integral non-linearity
(optimum)
Maximum error with respect to
the best line fit. Centered
magnet without calibration,
TAMB =25 ºC.
± 0.5
deg
Integral non-linearity
(optimum)
Maximum error with respect to
the best line fit.
Centered magnet without
calibration,
TAMB = -40ºC to 125ºC
± 0.9
deg
INL
Integral non-linearity
Best line fit = (Errmax – Errmin) / 2
Over displacement tolerance
with 6mm diameter magnet,
without calibration,
TAMB = -40ºC to 125ºC
± 1.4
deg
DNL
Differential non-linearity
12-bit, no missing codes
± 0.044
deg
TN
Transition noise
1 sigma
0.06
deg
RMS
tPwrUp
Power-up time
Until status bit OCF = 1
20
ms
tdelay
System propagation
delay
absolute output : delay
of ADC, DSP and
absolute interface
96
μs
tdelayINC
System propagation
delay incremental output
192
μs
fS
Internal sampling rate for
absolute output
11.46
kHz
1
MHz
INLopt
INLtemp
CLK/SEL
Read-out frequency
Page 10
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9.38
Max. clock frequency to read
out serial data
10.42
ams Datasheet
[v2-00] 2016-Feb-05
AS5045B − Electrical Characteristics
Figure 9:
Integral and Differential Non-Linearity Example
4095 α 12bit code
4095
Actual curve
2
TN
DNL+1LSB
1
0
2048
Ideal curve
INL
0.09°
2048
0
0°
180°
360 °
α [degrees]
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
[v2-00] 2016-Feb-05
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AS5045B − Timing Characteristics
Timing Characteristics
TAMB = -40°C to 125°C, VDD5V = 3.0V to 3.6V (3V operation)
VDD5V = 4.5V to 5.5V (5V operation) unless otherwise noted.
Figure 10:
Timing Characteristics
Symbol
Parameter
Conditions
Min
Typ
Max
Units
100
ns
Synchronous Serial Interface (SSI)
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
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
tDOactive
tDOtristate
ns
1
MHz
Pulse Width Modulation Output
PWM frequency
Signal period = 4098μs ±10%
at TAMB = -40ºC to 125ºC
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
20
μs
fPWM
Programming Conditions
tPROG
Programming time per bit
Time to prog. a single fuse bit
10
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
tCHARGE
Page 12
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μs
ams Datasheet
[v2-00] 2016-Feb-05
AS5045B − Detailed Description
Detailed Description
The AS5045B 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 AS5045B 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 31).
The AS5045B 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 AS5045B is tolerant to magnet
misalignment and magnetic stray fields due to differential
measurement technique and Hall sensor conditioning circuitry.
Figure 11:
Typical Arrangement of AS5045B and Magnet
ams Datasheet
[v2-00] 2016-Feb-05
Page 13
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AS5045B − Detailed Description
Synchronous Serial Interface (SSI)
Figure 12:
Synchronous Serial Interface with Absolute Angular Position Data
TCLK/2
CSn
tCSn
tCLK FE
1
CLK
D11
DO
D10 D9
D8
D7
D6
D5
1
18
8
D4
D3
D2
D1
D0
OCF COF
LIN
tCLK FE
Mag Mag Even
INC DEC PAR
D11
tDO valid
tDO active
Angular Position Data
Status Bits
tDO Tristate
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 t CSn.
Page 14
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ams Datasheet
[v2-00] 2016-Feb-05
AS5045B − Detailed Description
Data Content
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 D11:D0
is invalid. The absolute output maintains the last valid angular
value.
This alarm can 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 D11:D0 can still be used, but can
contain invalid data. This warning can be resolved by bringing
the magnet within the X-Y-Z tolerance limits.
Even Parity bit for transmission error detection of bits 1 to 17
(D11 to 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):
1. MagInc=MagDec=1 is only recommended in YELLOW mode (see Figure 14).
ams Datasheet
[v2-00] 2016-Feb-05
Page 15
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AS5045B − Detailed Description
Z-Axis Range Indication (Push Button Feature,
Red/Yellow/Green Indicator). The AS5045B 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).
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
Hardware
Pins
Status Bits
OTP: Mag CompEn = 1 (Red-Yellow-Green)
Mac
INC
Mag
DEC
LIN
Mac
INCn
Mag
DECn
0
0
0
Off
Off
No distance change
Magnetic input field OK (GREEN range, ~45mT to 75mT)
1
1
0
On
Off
YELLOW range: magnetic field is ~ 25mT to 45mT or
~75mT to 135mT. The AS5045B can still be operated in this
range, but with slightly reduced accuracy.
1
1
1
On
On
RED range: magnetic field is ~~135mT. It is still
possible to operate the AS5045B in the red range, but not
recommended.
All other combinations
n/a
n/a
Not available
Description
Note(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 can 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).
Page 16
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[v2-00] 2016-Feb-05
AS5045B − Detailed Description
Incremental Mode
The AS5045B has an internal interpolator block. This function
is used if the input magnetic field is to 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 (10-bit and 12-bit), 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.
Figure 15:
Incremental Mode_Table
Mode
Default
mode
10-bit
Incremental
mode
(low DNL)
12-bit
Incremental
mode
(high DNL)
Sync mode
Description
AS5145 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 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.
ams Datasheet
[v2-00] 2016-Feb-05
Output
Md1
Output
Md0
0
0
0
1
Resolution
Dtest1_A and
DTest2_B
Pulses
10
256
Index
Width
1/3 LSB
1
0
1
1
12
1024
Page 17
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AS5045B − Detailed Description
Incremental Power-Up Lock Option
After power-up, the incremental outputs can optionally be
locked or unlocked, depending on the status of the CSn pin:
• CSn = low at power-up: CSn has an internal pull-up resistor
and must be externally pulled low ( R ext ≤ 5kΩ ). If Csn is
low at power-up, the incremental outputs (A, B, Index) will
be high until the internal offset compensation is finished.
This unique state (A=B=Index = high) can be used as an
indicator for the external controller to shorten the waiting
time at power-up. Instead of waiting for the specified
maximum power up-time (0), the controller can start
requesting data from the AS5045B as soon as the state
(A=B=Index = high) is cleared.
• CSn = high or open at power-up: In this mode, the
incremental outputs (A, B, Index) will remain at logic high
state, until CSn goes low or a low pulse is applied at CSn.
This mode allows intentional disabling of the incremental
outputs until, for example the system microcontroller is
ready to receive data.
Figure 16:
Incremental Output
ClockWise
Programmed
Zero Position
Counter ClockWise
A
B
1 LSB
I
3 LSB
The hysteresis trimming is done at the final test (factory
trimming) and set to 4 LSB, related to a 12-bit number.
Incremental Output Hysteresis
To avoid flickering incremental outputs at a stationary magnet
position, a hysteresis is introduced. In case of a rotational
direction change, the incremental outputs have a hysteresis of
4 LSB. Regardless of the programmed incremental resolution,
the hysteresis of 4 LSB always corresponds to the highest
resolution of 12-bit. In absolute terms, the hysteresis is set to
0.35 degrees for all resolutions. For constant rotational
directions, every magnet position change is indicated at the
incremental outputs (see Figure 17). For example, if the magnet
turns clockwise from position “x+3“ to “x+4“, the incremental
output would also indicate this position accordingly.
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ams Datasheet
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AS5045B − Detailed Description
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
Incremental
Output
Indication
Hysteresis :
0.35°
X +6
X +5
X +4
X +3
X +2
X +1
X
X
X +1 X +2 X +3 X +4 X +5 X +6
Magnet Position
Clockwise Direction
Counterclockwise Direction
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.
ams Datasheet
[v2-00] 2016-Feb-05
Page 19
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AS5045B − Detailed Description
Sync Mode
This mode is used to synchronize the external electronic with
the AS5045B. In this mode two signals are provided at the pins
DTEST1_A and DTEST2_B. By setting Bit 48 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 sine and 16 bit cosine 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.
Daisy Chain Mode
The daisy chain mode allows connection of several AS5045Bs
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).
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ams Datasheet
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AS5045B − Detailed Description
Figure 19:
Daisy Chain Hardware Configuration
AS5045B
2nd Device
AS5045B
1st Device
µC
Data IN
PDIO
DO
DO
PDIO
CSn
CLK
CSn
AS5045B
last Device
DO
CLK
PDIO
CSn
CLK
CLK
CSn
Figure 20:
Daisy Chain Mode Data Transfer
CSn
tCLK FE
TCLK/2
1
CLK
D11
DO
tDO active
tDO valid
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
OCF COF
LIN
Mag Mag Even
INC DEC PAR
Status Bits
Angular Position Data
1st Device
ams Datasheet
[v2-00] 2016-Feb-05
D
18
8
1
2
3
D11
D10
D9
Angular Position Data
2nd Device
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AS5045B − Detailed Description
Pulse Width Modulation (PWM) Output
The AS5045B provides a pulse width modulated output (PWM),
whose duty cycle is proportional to the measured angle. For
angle position 0 to 4094
(EQ1)
t ⋅ 4098
( t on + t off )
on
-–1
Position = -------------------------
Examples:
1. An angle position of 180° will generate a pulse width
ton = 2049μs and a pause toff of 2049 μs resulting in
Position = 2048 after the calculation:
2049 * 4098 / (2049 + 2049) -1 = 2048
2. An angle position of 359.8° 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 359.9° will generate a pulse width
ton = 4097μs and a pause toff of 1 μs 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
Angle
PWMIN
0 deg
(Pos 0)
1µs
4098µs
PWMAX
359.91 deg
(Pos 4095)
4097µs
1/fPWM
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ams Datasheet
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AS5045B − Detailed Description
Changing the PWM Frequency
The PWM frequency of the AS5045B can be divided by two by
setting a bit (PWMhalfEN) in the OTP register (see Programming
the AS5045B). 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
4097
μs
• Position 4095d
• Angle 359.91 deg
Signal period: 4097μs
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
PWMIN
MIN pulse width
2
μs
• Position 0d
• Angle 0 deg
PWMAX
MAX pulse width
8194
μs
• Position 4095d
• Angle 359.91 deg
ams Datasheet
[v2-00] 2016-Feb-05
Note
Signal period: 8194μs
Page 23
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AS5045B − 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 AS5045B can be used as direct
replacement of potentiometers.
Figure 24:
Simple 2nd Order Passive RC Low Pass Filter
Pin12
R2
R1
analog out
PWM
VDD
C1
C2
0V
Pin7
0º
360º
VSS
Figure 21 shows an example of a simple passive low pass filter
to generate the analog output.
(EQ2)
R1,R2 ≥ 10k Ω
C1,C2 ≥ 2.2μF / 6V
R1 should be greater than or equal to 4k7 to avoid loading of
the PWM output. Larger values of Rx and Cx will provide better
filtering and less ripple, but will also slow down the response
time.
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ams Datasheet
[v2-00] 2016-Feb-05
AS5045B − Application Information
Application Information
The benefits of AS5045B are as follows:
• Complete system-on-chip
• Flexible system solution provides absolute and PWM
outputs simultaneously
• Ideal for applications in harsh environments due to
contactless position sensing
• No calibration required
• No temperature compensation necessary
Programming the AS5045B
After power-on, programming the AS5045B is enabled with the
rising edge of CSn with PDIO = high and CLK = low.
The AS5045B 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 (either with 3.3V or 5V supply).
The OTP consists of 52 bits, of which 21 bits are available for
user programming. The remaining 31 bits contain factory
settings and a unique chip identifier (Chip-ID).
A single OTP cell can be programmed only once. Per default,
the cell is “0”; a programmed cell will contain a “1”. While it is
not possible to reset a programmed bit from “1” to “0”, multiple
OTP writes are possible, as long as only unprogrammed “0”-bits
are programmed to “1”.
Independent of the OTP programming, it is possible to
overwrite the OTP register temporarily with an OTP write
command at any time. This setting will be cleared and
overwritten with the hard programmed OTP settings at each
power-up sequence or by a LOAD operation. Use application
note AN514X_10 to get more information about the
programming options.
The OTP memory can be accessed in the following ways:
• Load Operation: The Load operation reads the OTP fuses
and loads the contents into the OTP register. A Load
operation is automatically executed after each
power-on-reset.
• Write Operation: The Write operation allows a temporary
modification of the OTP register. It does not program the
OTP. This operation can be invoked multiple times and will
remain set while the chip is supplied with power and while
the OTP register is not modified with another Write or
Load operation.
ams Datasheet
[v2-00] 2016-Feb-05
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AS5045B − Application Information
• Read Operation: The Read operation reads the contents
of the OTP register, for example to verify a Write command
or to read the OTP memory after a Load command.
• Program Operation: The Program operation writes the
contents of the OTP register permanently into the OTP
ROM.
• Analog Readback Operation: The Analog Readback
operation allows a quantifiable verification of the
programming. For each programmed or unprogrammed
bit, there is a representative analog value (in essence, a
resistor value) that is read to verify whether a bit has been
successfully programmed or not.
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(see
Figure 27).
Note(s): The zero position value can also be modified before
programming, e.g. to program an electrical zero position that
is 180º (half turn) from the mechanical zero position, just add
2048 to the value read at the mechanical zero position and
program the new value into the OTP register.
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ams Datasheet
[v2-00] 2016-Feb-05
AS5045B − Application Information
OTP Memory Assignment
Figure 25:
OTP Bit Assignment
Symbol
Factory Bit 1
PMW frequency Index pulse
width
51
PWMhalfEN_Index width
50
MagCompEn
49
pwmDIS
Disable PWM
48
Reserved
47
Reserved
12 bit inc.
(programmed by ams)
bit 47 to 1, bit 48 to 0
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
:
:
20
FS 8
19
FS 9
18
FS 10
Alarm mode (programmed by
ams to 1)
12-bit Zero Position
Direction
Redundancy Address
Factory Bit
ams Datasheet
[v2-00] 2016-Feb-05
Customer Section
mbit1
Function
Factory Section
Bit
Page 27
Document Feedback
AS5045B − Application Information
Symbol
17
ChipID0
16
ChipID1
:
:
0
ChipID17
Function
ID Section
Bit
18-bit Chip ID
mbit0
Factory Bit 0
User Selectable Settings
The AS5045B 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
• 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 AS5045B can also be operated without programming. The
default, un-programmed setting is:
• 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. In case when the programming of one bit failed
this function can be used. With an address RA(4:0) one bit can
be selected and programmed.
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ams Datasheet
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AS5045B − Application Information
0
0
00001
1
0
0
00010
0
1
00011
0
00100
Z0
Z1
Z2
Z3
Z4
Z5
Z6
Z7
Z8
Z9
Z10
Z11
CCW
pwmDIS
0
Reserved
MagCompEN
00000
Reserved
Address
PWMhalfEN_Indexwidth
Figure 26:
Redundancy Addressing
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
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
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
01100
0
0
0
0
0
0
0
0
0
0
0
1
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
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
[v2-00] 2016-Feb-05
Page 29
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AS5045B − 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.
OTP Register Entry and Exit Condition
For timing options, refer to Programming the AS5045B.
Figure 27:
OTP Access Timing Diagram
OTP Access
Setup Condition
CSn
PDIO
CLK
Operation Mode Selection
Exit Condition
To avoid accidental modification of the OTP during normal
operation, each OTP access (Load, Write, Read, Program)
requires a defined entry and exit procedure, using the CSn, PDIO
and CLK signals as shown in Figure 27.
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ams Datasheet
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AS5045B − Application Information
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 28). 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 will
show values larger than 128. These magnets are still properly
aligned as long as the difference between highest and lowest
value over one full turn is at a minimum.
The Alignment mode can be reset to normal operation by a
power-on-reset (disconnect / re-connect power supply) or by a
falling edge on CSn with PDIO = low.
Figure 28:
Enabling the Alignment Mode
PDIO
CSn
2µs
min.
AlignMode enable
Read-out
via SSI
exit AlignMode
Read-out
via SSI
2µs
min.
Figure 29:
Exiting Alignment Mode
PDIO
CSn
ams Datasheet
[v2-00] 2016-Feb-05
Page 31
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AS5045B − Application Information
3.3V / 5V Operation
The AS5045B 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 30).
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 30) with recommended 2.2μF.
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 30:
Connections for 5V / 3.3V Supply Voltages
5V Operation
3.3V Operation
2.2 ... 10µF
VDD3V3
VDD3V3
100nF
VDD5V
100nF
LDO
Internal
VDD
VDD5V
LDO
Internal
VDD
DO
DO
PWM
4.5 - 5.5V
VSS
Page 32
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I
N
T
E
R
F
A
C
E
CLK
CSn
+
-
-
+
3.0 - 3.6V
PDIO
VSS
I
N
T
E
R
F
A
C
E
PWM
CLK
CSn
PDIO
ams Datasheet
[v2-00] 2016-Feb-05
AS5045B − Application Information
A buffer capacitor of 100nF is recommended in both cases close
to pin VDD 5V. Note that pin VDD 3V3 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 can lead to larger
than normal jitter of the measured angle.
Selecting Proper Magnet
Typically the magnet is 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 to ±75mT
(peak).
The magnet’s field strength is verified using a gauss-meter. The
magnetic field Bv at a given distance, along a concentric circle
with a radius of 1.1mm (R1) is in the range of ±45mT to ±75mT
(see Figure 31).
Figure 31:
Typical Magnet (6x3mm) and Magnetic Field Distribution
typ. 6mm diameter
N
S
Magnet axis
R1
Magnet axis
Vertical field
component
R1 concentric circle;
radius 1.1mm
Vertical field
component
Bv
(45…75mT)
0
360
360
ams Datasheet
[v2-00] 2016-Feb-05
Page 33
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AS5045B − Application Information
Physical Placement of the Magnet
The best linearity can be achieved by placing the center of the
magnet exactly over the defined center of the chip as shown in
the drawing below:
Figure 32:
Defined Chip Center and Magnet Displacement Radius
3.9mm
3.9mm
2.4325mm
1
Defined
center
2.4325mm
Rd
Area of recommended maximum magnet misalignment
Magnet Placement
The magnet’s center axis must be aligned within a displacement
radius Rd of 0.25mm from the defined center of the IC. The
magnet can be placed below or above the device. The distance
can be chosen such that the magnetic field on the die surface
is within the specified limits (see Figure 32). The typical distance
“z” between the magnet and the package surface is 0.5mm to
1.5mm, provided the use of the recommended magnet material
and dimensions (6mm x 3mm). Larger distances are possible, as
long as the required magnetic field strength stays within the
defined limits.
A magnetic field outside the specified range still can be
detected by the chip. But the out-of-range condition will be
indicated by MagINCn (pin 1) and MagDECn (pin 2), (see
Figure 4).
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AS5045B − Application Information
Failure Diagnostics
The AS5045B also offers several diagnostic and failure detection
features:
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 AS5045B 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) must 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 AS5045B, 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
[v2-00] 2016-Feb-05
Page 35
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AS5045B − 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. (see
Figure 33) 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 2x2mm (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.
Figure 33:
Example of Linearity Error Over XY Misalignment
6
5
4
° 3
800
500
2
200
1
-100
-800
-1000
-1000
-600
-400
0
-700
-200
200
600
y
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x
-400
400
1000
800
0
ams Datasheet
[v2-00] 2016-Feb-05
AS5045B − Application Information
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.
Figure 34:
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)x1.
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:
• 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 can be
further 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
15,000 rpm and higher).
ams Datasheet
[v2-00] 2016-Feb-05
Page 37
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AS5045B − Application Information
Note(s): Statistically, 1 sigma represents 68.27% of readings
and 3 sigma represents 99.73% of readings.
High Speed Operation
• Sampling Rate: The AS5045B samples the angular value
at a rate of 10.42k samples per second. Consequently, the
absolute outputs are updated each 96μs. At a stationary
position of the magnet, the sampling rate creates no
additional error.
• Absolute Mode: At a sampling rate of 10.4kHz, the
number of samples (n) per turn for a magnet rotating at
high speed can be calculated by
(EQ3)
n=
60 -------------------------rmp ⋅ 96μs
The upper speed limit is ~30,000 rpm. The only restriction
at high speed is that there will be fewer samples per
revolution as the speed increases (see Figure 13).
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 rpm. Therefore, the AS5045B has a built-in
interpolator, which ensures that there are no missing
pulses at the incremental outputs for rotational speeds of
up to 15,000 rpm, even at the highest resolution of 12 bits
(4096 pulses per revolution).
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.
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:
(EQ4)
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 AS5045B.
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ams Datasheet
[v2-00] 2016-Feb-05
AS5045B − Application Information
Internal Timing Tolerance
The AS5045B does not require an external ceramic resonator or
quartz. All internal clock timings for the AS5045B 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).
PWM output: A new angular value is updated every 96μs (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).
Temperature
Magnetic Temperature Coefficient
One of the major benefits of the AS5045B 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 AS5045B automatically
compensates for the varying magnetic field strength over
temperature. The magnet’s temperature drift does not need to
be considered, as the AS5045B 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 -40ºC to 125ºC = 165K.The
magnetic field change is: 165 x -0.12% = -19.8%, which
corresponds to 75mT at -40ºC and 60mT at 125ºC.
The AS5045B 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 can increase to less than 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 can 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
[v2-00] 2016-Feb-05
Page 39
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AS5045B − Package Drawings & Markings
Package Drawings & Markings
The device is available in SSOP 16 (5.3mm x 6.2mm).
Figure 35:
Package Drawings and Dimensions
RoHS
Green
Symbol
Min
Nom
Max
A
A1
A2
b
c
D
E
E1
e
L
L1
L2
R
Q
N
1.73
0.05
1.68
0.22
0.09
5.90
7.40
5.00
0.55
0.09
0º
1.86
0.13
1.73
0.315
0.17
6.20
7.80
5.30
0.65 BSC
0.75
1.25 REF
0.25 BSC
4º
16
1.99
0.21
1.78
0.38
0.25
6.50
8.20
5.60
0.95
8º
YYWWMZZ @
AS5045B
Note(s):
1. Dimensions and tolerancing conform to ASME Y14.5M-1994.
2. All dimensions are in millimeters. Angles are in degrees.
Figure 36:
Package Code: YYWWMZZ
YY
WW
M
ZZ
@
Last two digits of the
manufacturing year
Manufacturing week
Plant identifier
Assembly
traceability code
Sublot identifier
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ams Datasheet
[v2-00] 2016-Feb-05
AS5045B − Package Drawings & Markings
Figure 37:
Vertical Cross Section of SSOP-16
Note(s):
1. All dimensions in mm.
ams Datasheet
[v2-00] 2016-Feb-05
Page 41
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AS5045B − Package Drawings & Markings
Recommended PCB Footprint
Figure 38:
PCB Footprint
Recommended
Footprint Data
Symbol
mm
A
B
C
D
E
Page 42
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9.02
6.16
0.46
0.65
5.01
ams Datasheet
[v2-00] 2016-Feb-05
AS5045B − Ordering & Contact Information
Ordering & Contact Information
The devices are available as the standard products shown in
Figure 39.
Figure 39:
Ordering Information
Ordering Code
Package
AS5045B-ASST
SSOP 16
(5.3mm x 6.2mm)
AS5045B-ASSM
Description
Delivery
Form
Delivery
Quantity
Pre-programmed 12-bit
incremental (125 °C)
Tape&Reel (13”)
2000 pcs/reel
Pre-programmed 12-bit
incremental (125 °C)
Tape&Reel (7”)
500 pcs/reel
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 Premstaetten
Austria, Europe
Tel: +43 (0) 3136 500 0
Website: www.ams.com
ams Datasheet
[v2-00] 2016-Feb-05
Page 43
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AS5045B − 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.
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ams Datasheet
[v2-00] 2016-Feb-05
AS5045B − Copyrights & Disclaimer
Copyrights & Disclaimer
Copyright ams AG, Tobelbader Strasse 30, 8141 Premstaetten,
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.
ams Datasheet
[v2-00] 2016-Feb-05
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AS5045B − Document Status
Document Status
Document Status
Product Preview
Preliminary Datasheet
Datasheet
Datasheet (discontinued)
Page 46
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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
ams Datasheet
[v2-00] 2016-Feb-05
AS5045B − Revision Information
Revision Information
Changes from 1.1 (2014-Sep-16) to current revision 2-00 (2016-Feb-05)
Page
Content was updated to the latest ams design
Added benefits to the Figure 1
1
Updated Figure 6
6
Updated text above Figure 7
9
Updated text above Figure 8
10
Updated text above Figure 10
12
Updated Figure 36
40
Updated Figure 39
43
Note(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.
ams Datasheet
[v2-00] 2016-Feb-05
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AS5045B − Content Guide
Content Guide
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1
1
2
2
General Description
Key Benefits & Features
Applications
Block Diagram
3
5
Pin Assignment
Absolute Maximum Ratings
6
9
10
Electrical Characteristics
Magnetic Input Specification
System Specifications
12
Timing Characteristics
13
14
17
20
20
20
22
23
24
Detailed Description
Synchronous Serial Interface (SSI)
Incremental Mode
Sync Mode
Sin/Cosine Mode
Daisy Chain Mode
Pulse Width Modulation (PWM) Output
Changing the PWM Frequency
Analog Output
25
25
26
27
28
28
28
30
30
31
32
33
34
34
35
35
35
36
36
37
38
38
39
39
39
Application Information
Programming the AS5045B
Zero Position Programming
OTP Memory Assignment
User Selectable Settings
OTP Default Setting
Redundancy
Redundant Programming Option
OTP Register Entry and Exit Condition
Alignment Mode
3.3V / 5V Operation
Selecting Proper Magnet
Physical Placement of the Magnet
Magnet Placement
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
ams Datasheet
[v2-00] 2016-Feb-05
AS5045B − Content Guide
ams Datasheet
[v2-00] 2016-Feb-05
40
42
Package Drawings & Markings
Recommended PCB Footprint
43
44
45
46
47
Ordering & Contact Information
RoHS Compliant & ams Green Statement
Copyrights & Disclaimer
Document Status
Revision Information
Page 49
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