AMS AS5045B Position Sensor Datasheet
Below you will find brief information for magnetic position sensor AS5045B. The AS5045B is a contactless magnetic position sensor that provides 12-bit resolution over a full turn of 360 degrees. The sensor can be used in a variety of applications, including motor control, robotics, and elevator doors. It has an internal voltage regulator that allows it to operate at either 3.3V or 5V supplies.
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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.
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
• Highest reliability and durability
• Simple programming
• Multiple interfaces
• Ideal for motor applications
• Failure diagnostics
• Easy setup
Benefits
• Great flexibility at a huge application area
• Small form factor
• Robust environmental tolerance
Features
• Contactless high resolution rotational position encoding over a full turn of 360 degrees
• Simple user-programmable zero position and settings
• Serial communication interface (SSI)
• 10-bit pulse width modulated (PWM) output
• Quadrature A/B and Index output signal
• Rational speeds up to 30,000 rpm
• Failure detection mode for magnet placement monitoring and loss of power supply
• Serial read-out of multiple interconnected AS5045B devices using Daisy Chain mode
• Detects movement of magnet in Z-axis (Red-Yellow-Green indicator)
• SSOP 16 (5.3mm x 6.2mm)
• Wide temperature range: -40°C to 125°C
ams Datasheet
[v2-00] 2016-Feb-05
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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.
Figure 2:
Block Diagram Rotary Position Sensor IC
Block Diagram
The functional blocks of this device are shown below:
VDD5V
VDD3V3
LDO 3.3V
Hall Array
&
Frontend
Amplifier
Sin
Cos
PWM
Interface
ATAN
(Cordic)
Ang
Mag
Absolute
Interface
(SSI)
OTP
Register
AS5045B
Incremental
Interface
MagINCn
MagDECn
PWM
DO
CSn
A
I
B
CLK
PDIO
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AS5045B − Pin Assignment
Pin Assignment
Figure 3:
Pin Diagram (Top View)
MagINCn
MagDECn
A
B
NC
I
VSS
PDIO
1
2
3
4
7
8
5
6
14
13
12
11
10
9
16
15
VDD5V
VDD3V3
NC
NC
PWM
CSn
CLK
DO
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 4:
Pin Description
Pin Name
MagINCn
MagDECn
A
B
NC
I
VSS
PDIO
DO
3
4
5
6
7
Pin
Number
1
2
8
9
Pin Type Description
Digital output open drain
Digital output
-
Digital output
Supply pin
Digital input pull-down
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
Quadrature output A (1024 Pulses)
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 (74k
Ω). Connect this pin to VSS if programming is not required.
Digital output/ tri-state
Data Output of Synchronous Serial Interface
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AS5045B − Pin Assignment
CSn
PWM
NC
NC
VDD3V3
VDD5V
Pin Name
CLK
Pin
Number
10
11
12
13
14
15
16
Pin Type Description
Digital input,
Schmitt-Trigger input
Digital input pull-down,
Schmitt-Trigger input
Clock Input of Synchronous Serial Interface;
Schmitt-Trigger input
Chip Select. Active low. Schmitt-Trigger input, internal pull-up resistor (50k
Ω)
Digital output
-
-
Supply pin
Supply pin
Pulse Width Modulation
Must be left unconnected
Must be left unconnected
3V-Regulator output, internally regulated from
VDD5V. Connect to VDD5V for 3V supply voltage.
Do not load externally.
Positive supply voltage, 3.0V to 5.5V
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
). This pin is also used as digital input to shift serial data through the device in daisy chain configuration, (see page
).
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
) and programming mode (see
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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AS5045B − Absolute Maximum Ratings
Absolute Maximum Ratings
Stresses beyond those listed in
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
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
-0.3
Electrical Parameters
7 V DC supply voltage at pin VDD5V
DC supply voltage at pin
VDD3V3
Input pin voltage -0.3
V Except VDD3V3
Input current (latchup immunity) -100 100 mA
Electrostatic Discharge
EIA/JESD78 Class II Level A
Electrostatic discharge
VDD5V
+0.3
± 2 kV JESD22-A114E
Temperature Ranges and Storage Conditions
Storage temperature
Package body temperature
-55
5
150
260
V
ºC
ºC
Min -67ºF; Max 302ºF
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).
Relative humidity non-condensing
Moisture sensitivity level (MSL)
5
3
85 %
Represents a maximum floor time of 168h
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AS5045B − Electrical Characteristics
Electrical Characteristics
T
AMB
= -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
Operating Conditions
T
AMB
I supp
Ambient temperature
Supply current
-40°F to 257°F
VDD5V
VDD3V3
VDD5V
VDD3V3
Supply voltage at pin
VDD5V
Voltage regulator output voltage at pin
VDD3V3
Supply voltage at pin
VDD5V
Supply voltage at pin
VDD3V3
5V operation
3.3V operation
(pin VDD5V and VDD3V3 connected)
V
V
I
V
V
ON off
PROG
ProgOff
PROG
Power-on reset thresholds On voltage;
300mV typ. hysteresis
Power-on reset thresholds Off voltage;
300mV typ. hysteresis
DC supply voltage 3.3V
(VDD3V3)
Programming voltage
Programming Conditions
Voltage applied during programming
Programming voltage off level
Programming current
Line must be discharged to this level
Current during programming
R programmed
Programmed fuse resistance (log 1)
R unprogrammed
Unprogrammed fuse resistance (log 0)
10μA max. current @
100mV
2mA max. current @
100mV
Min
-40
4.5
3.0
3.0
3.0
1,37
1.08
3.3
0
10k
50
Typ Max Units
16
5.0
3.3
3.3
3.3
2.2
1.9
125
21
5.5
3.6
3.6
3.6
2.9
2.6
3.6
1
100
∞
100
°C mA
V
V
V
V
V mA
Ω
Ω
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AS5045B − Electrical Characteristics
Symbol Parameter Condition Min Typ Max Units
V
V
IH
DC Characteristics CMOS Schmitt-Trigger Inputs: CLK, CSn (CSn = Internal Pull-Up)
High level input voltage Normal operation
0.7 *
VDD5V
V
IL
Low level input voltage
0.3 *
VDD5V
Ion-
V
Ioff
Schmitt trigger hysteresis
1
I
LEAK
Input leakage current CLK only -1 1
I
V iL
IH
Pull-up low level input current
CSn only, VDD5V: 5.0V
-30
DC Characteristics CMOS / Program Input: PDIO
High level input voltage
0.7 *
VDD5V
-100
VDD5V
V
PROG
High level input voltage During programming 3.3
3.6
V
IL
Low level input voltage
0.3 *
VDD5V
I
IH
High level input current VDD5V: 5.5V
30 100
I
OZ
DC Characteristics CMOS Output Open Drain: MagINCn, MagDECn
Open drain leakage current
1
V
V
I
OL
O
OH
Low level output voltage
Output current
VDD5V: 4.5V
VDD5V: 3V
DC Characteristics CMOS Output: PWM
High level output voltage
VDD5V
– 0.5
VSS +
0.4
4
2
V
I
OL
O
Low level output voltage
Output current
VDD5V: 4.5V
VDD5V: 3V
VSS
+0.4
4
2
V
V
V
μA
V
V
V
μA
μA
V mA
V
V mA
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AS5045B − Electrical Characteristics
Symbol
V
OH
V
OL
I
O
V
OH
V
OL
I
O
I
OZ
Parameter Condition Min
DC Characteristics CMOS Output: A, B, Index
High level output voltage
VDD5V
– 0.5
Typ Max Units
V
Low level output voltage
Output current
VDD5V: 4.5V
VDD5V: 3V
DC Characteristics Tri-state CMOS Output: DO
High level output voltage
VDD5V
– 0.5
VSS
+0.4
4
2
V mA
V
Low level output voltage
Output current
Tri-state leakage current
VDD5V: 4.5V
VDD5V: 3V
VSS
+0.4
4
2
1
V mA
μA
Note(s):
1. Either with 3.3V or 5V supply.
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AS5045B − Electrical Characteristics
Magnetic Input Specification
T
AMB
= -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
d mag t mag
B pk
B off f mag_abs
Disp
Ecc
Parameter Condition
Diameter
Recommended magnet: Ø 6mm x 2.5mm for cylindrical magnets
Thickness
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
Constant magnetic stray field Magnetic offset
Input frequency
(rotational speed of magnet)
153 rpm @ 4096 positions/rev
Displacement radius
Eccentricity
Max. offset between defined device center and magnet axis
)
Eccentricity of magnet center to rotational axis
Recommended magnet material and temperature drift
NdFeB (Neodymium Iron Boron)
SmCo (Samarium Cobalt)
Min Typ Max Unit
6 4
2.5
mm mm
45
-0.12
-0.035
75
± 10
2.54
0.25
100 mT mT
Hz mm
μm
%/K
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AS5045B − Electrical Characteristics
System Specifications
T
AMB
= -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
INL opt
INL temp
INL
DNL
Parameter Condition
Resolution
Integral non-linearity
(optimum)
Integral non-linearity
(optimum)
0.088 deg
Maximum error with respect to the best line fit. Centered magnet without calibration,
T
AMB
=25 ºC.
Maximum error with respect to the best line fit.
Centered magnet without calibration,
T
AMB
= -40ºC to 125ºC
Integral non-linearity
Best line fit = (Err max
– Err min
) / 2
Over displacement tolerance with 6mm diameter magnet, without calibration,
T
AMB
= -40ºC to 125ºC
Differential non-linearity 12-bit, no missing codes
Min Typ Max Unit
12 bit
± 0.5
± 0.9
± 1.4
deg deg deg
TN Transition noise 1 sigma
± 0.044
deg
0.06
deg
RMS
20 ms t t t
PwrUp delay delayINC f
S
CLK/SEL
Power-up time
System propagation delay absolute output : delay of ADC, DSP and absolute interface
System propagation delay incremental output
Internal sampling rate for absolute output
Until status bit OCF = 1
Read-out frequency
Max. clock frequency to read out serial data
96
192
9.38
10.42
11.46
1
μs
μs kHz
MHz
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AS5045B − Electrical Characteristics
Figure 9:
Integral and Differential Non-Linearity Example
4095
α
2
1
0
Actual curve
TN
0.09°
INL
DNL+1LSB
Ideal curve
2048
2048
0
0
°
4095
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.
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AS5045B − Timing Characteristics
Timing Characteristics
T
AMB
= -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
t
DOactive t
CLKFE
T
CLK/2 t
DOvalid t
DOtristate t
CSn f
CLK f
PWM
PW
MIN
PW
MAX t
PROG t
CHARGE f
LOAD f
READ f
WRITE
Parameter Conditions Min Typ Max Units
Data output activated
(logic high)
Synchronous Serial Interface (SSI)
Time between falling edge of
CSn and data output activated
First data shifted to output register
Time between falling edge of
CSn and first falling edge of
CLK
Start of data output
Data output valid
Rising edge of CLK shifts out one bit at a time
Time between rising edge of
CLK and data output valid
Data output tri-state
Pulse width of CSn
After the last bit DO changes back to “tri-state”
CSn =high; To initiate read-out of next angular position
Read-out frequency
Clock frequency to read out serial data
Pulse Width Modulation Output
PWM frequency
Signal period = 4098μs ±10% at T
AMB
= -40ºC to 125ºC
Minimum pulse width Position 0d; angle 0 degree
500
500
500
>0
220
0.90
244
1
100
413
100
1
268
1.10
Maximum pulse width
Position 4098d; angle 359.91 degrees
Programming Conditions
3686 4096 4506
Programming time per bit Time to prog. a single fuse bit
Refresh time per bit
LOAD frequency
Time to charge the cap after t
PROG
Data can be loaded at n x 2μs
10
1
20
500 ns ns ns ns ns ns
MHz
Hz
μs
μs
μs
μs kHz
READ frequency
WRITE frequency
Read the data from the latch
Write the data to the latch
2.5
2.5
MHz
MHz
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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
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
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AS5045B − Detailed Description
Synchronous Serial Interface (SSI)
Figure 12:
Synchronous Serial Interface with Absolute Angular Position Data
CSn
CLK
DO t t
CLK FE
T
CLK/2
1
DO active t
CSn
8
18
D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 OCF COF LIN t
DO valid
Angular Position Data Status Bits
Mag
INC
Mag
DEC
Even
PAR t
DO Tristate t
CLK FE
1
D11
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 t
CLK 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
.
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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 COF
1 0
LIN
0
Mag INC
1
1
0
0
Note(s):
1. MagInc=MagDec=1 is only recommended in YELLOW mode (see
).
Mag DEC
0
1
0
1
Parity
Even checksum of bits 1:15
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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
).
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
1
1
Status Bits
Mac
INC
Mag
DEC
0 0
LIN
0
1
1
0
1
All other combinations
Hardware
Pins
Mac
INCn
Mag
DECn
Off Off
On
On n/a
Off
On n/a
OTP: Mag CompEn = 1 (Red-Yellow-Green)
Description
No distance change
Magnetic input field OK (GREEN range, ~45mT to 75mT)
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.
RED range: magnetic field is ~<25mT or >~135mT. It is still possible to operate the AS5045B in the red range, but not recommended.
Not available
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
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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 Description
Default mode
Sync mode
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).
10-bit
Incremental mode
(low DNL)
12-bit
Incremental mode
(high 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.
In this mode a control signal is switched to
DTEST1_A and
DTEST2_B.
Output
Md1
Output
Md0
Resolution
Dtest1_A and
DTest2_B
Pulses
Index
Width
0
0
1
1
0
1
0
1
10
12
256
1024
1/3 LSB
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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
≤
5k
Ω
). 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
A
B
I
ClockWise
Programmed
Zero Position
1 LSB
3 LSB
Counter ClockWise
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
). 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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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
Clockwise Direction
Counterclockwise Direction
Magnet Position
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.
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Figure 18:
Dtest1_A and DTest2_B
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.
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Every rising edge at DTEST1_A indicates that new data in the device is available. With this signal it is possible to trigger an external customer Microcontroller (interrupt) and start the SSI readout. DTEST2_B indicates the phase of available data.
Sine/Cosine Mode
This mode can be enabled by setting the OTP Factory-bit FS2.
If this mode is activated the 16 bit 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
). 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
).
ams Datasheet
[v2-00] 2016-Feb-05
AS5045B − Detailed Description
Figure 19:
Daisy Chain Hardware Configuration
µC
Data IN
CLK
CSn
DO
AS5045B
1 st
Device
PDIO
2
AS5045B nd
Device
DO PDIO
AS5045B last Device
DO PDIO
CSn CLK CSn CLK CSn
CLK
Figure 20:
Daisy Chain Mode Data Transfer
CSn
CLK t
CLK FE
T
CLK/2
1 8 18
D
1 2
3
DO t
DO active
D11
D10 D9 D8 D7 D6 D5 D4
D3 D2 D1 D0 OCF COF LIN
Mag
INC
Mag
DEC
Even
PAR t
DO valid Angular Position Data Status Bits
1 st
Device
D11 D10 D9
Angular Position Data
2 nd
Device
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AS5045B − Detailed Description
(EQ1)
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
Position =
( t t on on
⋅
--------------------------
+
4098 t off
)
– 1
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
0 deg
(Pos 0)
PW
MIN
1µs
359.91 deg
(Pos 4095)
PW
MAX
1/f
PWM
4098µs
4097µs
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AS5045B − Detailed Description
Figure 22:
PWM Signal Parameters (Default Mode)
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
). With PWMhalfEN = 0 the PWM timing is as shown in
.
Symbol
f
PWM
PW
MIN
PW
MAX
Symbol
f
PWM
PW
MIN
PW
MAX
Parameter
PWM frequency
MIN pulse width
MAX pulse width
Parameter
PWM frequency
MIN pulse width
MAX pulse width
Typ
244
1
4097
Typ
122
2
8194
Unit
Hz
μs
μs
Unit
Hz
μs
μs
Note
Signal period: 4097μs
• Position 0d
• Angle 0 deg
• Position 4095d
• Angle 359.91 deg
When PWMhalfEN = 1, the PWM timing is as shown in
Figure 23:
PWM Signal Parameters with Half Frequency (OTP Option)
Note
Signal period: 8194μs
• Position 0d
• Angle 0 deg
• Position 4095d
• Angle 359.91 deg
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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
PWM
Pin7
VSS
R1
C1
R2
C2 analog out
VDD
0V
0º 360º
(EQ2)
Figure 21 shows an example of a simple passive low pass filter
to generate the analog output.
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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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.
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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
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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AS5045B − Application Information
OTP Memory Assignment
51
50
49
48
47
23
:
20
19
18
27
26
25
24
33
:
29
28
46
:
35
34
Figure 25:
OTP Bit Assignment
Bit Symbol
mbit1
PWMhalfEN_Index width
MagCompEn pwmDIS
Reserved
Reserved
FS 5
:
FS 8
FS 9
FS 10
FS 1
FS 2
FS 3
FS 4
RA0
:
RA4
FS 0
Z0
:
Z11
CCW
Function
Factory Bit 1
PMW frequency Index pulse width
Alarm mode (programmed by ams to 1)
Disable PWM
12 bit inc.
(programmed by ams) bit 47 to 1, bit 48 to 0
12-bit Zero Position
Direction
Redundancy Address
Factory Bit
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Bit
:
0
17
16
AS5045B − Application Information
Symbol
ChipID0
ChipID1
:
ChipID17 mbit0
Function
18-bit Chip ID
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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AS5045B − Application Information
Figure 26:
Redundancy Addressing
Address Z0 Z1 Z2 Z3 Z4 Z5 Z6 Z7 Z8 Z9 Z10 Z11
01000
01001
01010
01011
01100
01101
01110
01111
00000
00001
00010
00011
00100
00101
00110
00111
10000
10001
10010
10101
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
0
0
0
0
1
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
1
0
0
0
0
1
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
1
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
0
0
0
0
0
0
0
1
0
0
0
1
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
1
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
0
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
1
0
0
0
0
0
0
0
0
ams Datasheet
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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
Figure 27:
OTP Access Timing Diagram
CSn
PDIO
CLK
Setup Condition
Operation Mode Selection
OTP Access
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
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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
AlignMode enable
Read-out via SSI
Figure 29:
Exiting Alignment Mode
PDIO
CSn
2µs min.
2µs min.
exit AlignMode
Read-out via SSI
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AS5045B − Application Information
Figure 30:
Connections for 5V / 3.3V Supply Voltages
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
).
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.
5V Operation
100nF
VDD5V
+
4.5 - 5.5V
VDD3V3
LDO
2.2 ... 10µF
Internal
VDD
A
C
R
F
E
T
E
I
N
CLK
CSn
PDIO
VSS
3.3V Operation
VDD5V
+
3.0 - 3.6V
VSS
VDD3V3
LDO
A
C
R
F
E
T
E
I
N
Internal
VDD
DO
PWM
CLK
CSn
100nF
PDIO
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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:
Typical Magnet (6x3mm) and Magnetic Field Distribution
typ. 6mm diameter
Vertical field component
N
R1
S
Magnet axis
Magnet axis
Vertical field component
Bv
(45…75mT)
R1 concentric circle; radius 1.1mm
0
360
360
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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
1
3.9mm
3.9mm
Defined center
R d
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
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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 (~10k
Ω) 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
(~10k
Ω) 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.
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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
).
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
Z-axis in the 3D-graph.
Figure 33:
Example of Linearity Error Over XY Misalignment
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6
5
4
°
3
2
1
0
y
800
500
200
-100
x
-400
-700
-1000
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
-0.1
0
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
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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.
(EQ3)
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 n =
60
⋅ μs
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
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).
(EQ4)
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:
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.
ams Datasheet
[v2-00] 2016-Feb-05
AS5045B − Application Information
ams Datasheet
[v2-00] 2016-Feb-05
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 T on
and T off also have the same tolerance as the internal oscillator. If only the PWM pulse width
Ton is used to measure the angle, the resulting value also has this timing tolerance. However, this tolerance can be cancelled by measuring both Ton and T off
and calculating the angle from the duty cycle (see
Pulse Width Modulation (PWM) Output ).
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.
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AS5045B − Pack age Drawings & Mark ings
Package Drawings & Markings
Figure 35:
Package Drawings and Dimensions
The device is available in SSOP 16 (5.3mm x 6.2mm).
RoHS
Green
Symbol Min Nom Max
R
Q
N e
L
L1
L2 c
D
E
E1
A
A1
A2 b
-
0.55
-
-
0.09
0º
1.73
0.05
1.68
0.22
0.09
5.90
7.40
5.00
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
-
0.95
-
-
-
8º
1.99
0.21
1.78
0.38
0.25
6.50
8.20
5.60
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
Last two digits of the manufacturing year
WW M
Manufacturing week Plant identifier
ZZ
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
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Figure 38:
PCB Footprint
AS5045B − Pack age Drawings & Mark ings
Recommended PCB Footprint
Recommended
Footprint Data
Symbol
C
D
A
B
E
mm
9.02
6.16
0.46
0.65
5.01
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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:
Ordering Information
Ordering Code
AS5045B-ASST
AS5045B-ASSM
Package Description
Delivery
Form
SSOP 16
(5.3mm x 6.2mm)
Pre-programmed 12-bit incremental (125 °C)
Pre-programmed 12-bit incremental (125 °C)
Tape&Reel (13”)
Tape&Reel (7”)
Delivery
Quantity
2000 pcs/reel
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: [email protected]
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
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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.
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AS5045B − Document Status
Document Status
Document Status
Product Preview
Preliminary Datasheet
Datasheet
Datasheet (discontinued)
Product Status
Pre-Development
Pre-Production
Production
Discontinued
Definition
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
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
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
Information in this datasheet is based on products which conform to specifications in accordance with the terms of ams AG standard warranty as given in the General Terms of
Trade, but these products have been superseded and should not be used for new designs
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ams Datasheet
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AS5045B − Revision Information
Revision Information
Changes from 1.1 (2014-Sep-16) to current revision 2-00 (2016-Feb-05)
Content was updated to the latest ams design
Added benefits to the Figure 1
Updated Figure 6
Updated text above Figure 7
Updated text above Figure 8
Updated text above Figure 10
Updated Figure 36
Updated Figure 39
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.
Page
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Content Guide
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AS5045B − Content Guide
1 General Description
1 Key Benefits & Features
2 Applications
2 Block Diagram
3 Pin Assignment
5 Absolute Maximum Ratings
6 Electrical Characteristics
9 Magnetic Input Specification
10 System Specifications
12 Timing Characteristics
13 Detailed Description
14 Synchronous Serial Interface (SSI)
17 Incremental Mode
20 Sync Mode
20 Sin/Cosine Mode
20 Daisy Chain Mode
22 Pulse Width Modulation (PWM) Output
23 Changing the PWM Frequency
24 Analog Output
25 Application Information
25 Programming the AS5045B
26 Zero Position Programming
27 OTP Memory Assignment
28 User Selectable Settings
28 OTP Default Setting
28 Redundancy
30 Redundant Programming Option
30 OTP Register Entry and Exit Condition
31 Alignment Mode
32 3.3V / 5V Operation
33 Selecting Proper Magnet
34 Physical Placement of the Magnet
34 Magnet Placement
35 Failure Diagnostics
35 Magnetic Field Strength Diagnosis
35 Power Supply Failure Detection
36 Angular Output Tolerances
36 Accuracy
37 Transition Noise
38 High Speed Operation
38 Propagation Delays
39 Internal Timing Tolerance
39 Temperature
39 Accuracy over Temperature
ams Datasheet
[v2-00] 2016-Feb-05
AS5045B − Content Guide
40 Package Drawings & Markings
42 Recommended PCB Footprint
43 Ordering & Contact Information
44 RoHS Compliant & ams Green Statement
45 Copyrights & Disclaimer
46 Document Status
47 Revision Information
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Key features
Contactless magnetic position sensor
12-bit resolution
Full turn 360 degree measurement
Multiple interfaces
Simple programming
Failure diagnostics
Daisy Chain mode
PWM Output
3.3V or 5V operation
Small form factor
Frequently asked questions
The AS5045B has a resolution of 0.0879º = 4096 positions per revolution.
The AS5045B can operate with either 3.3V or 5V supplies.
These pins (1 and 2) are magnetic field change indicators. They indicate movements of the used magnet towards or away from the device's surface.