AMS AS5245 Position Sensor Datasheet
تبلیغات
تبلیغات
AS5245
Programmable 360º Magnetic Angle
Encoder with Absolute SSI and PWM
Output
General Description
The AS5245 is a contactless magnetic angle encoder for accurate measurement up to 360º and includes two AS5145 devices in a punched stacked leadframe.
It is a system-ON-chip, combining integrated Hall elements, analog front end and digital signal processing in a single device.
To measure the angle, only a simple two-pole magnet, rotating over the center of the chip is required. The magnet may be placed above or below the IC.
The absolute angle measurement provides instant indication of the magnet’s angular position with a resolution of
0.0879º = 4096 positions per revolution. This digital data is available as a serial bit stream and as a PWM signal.
An internal voltage regulator allows operation of the AS5245 from 3.3V or 5.0V supplies.
The AS5245 is fully automotive qualified to AEC-Q100, grade 0.
and
datasheet.
Key Benefits & Features
The benefits and features of AS5245, Programmable 360º
Magnetic Angle Encoder with Absolute SSI and PWM Output are listed below:
Figure 1:
Added Value of Using AS5245
Benefits
No mechanical wear
High resolution absolute position sensing
Easy to use for motor control
Adjustable zero position
Tolerant to magnet misalignment
Usable for high speed applications
Tolerant to airgap variations
Features
•
Contactless high resolution rotational position encoding over a full turn of 360º
•
Two digital 12-bit absolute outputs
•
Quadrature A/B (10- or 12-bit) and Index output signal
•
User programmable zero position
•
Failure detection mode for magnet placement monitoring and loss of power supply
•
“Red-Yellow-Green” indicators display placement of magnet in Z-axis
•
Tolerant to magnet misalignment and air gap variations
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General Description
Benefits Features
Operates up to 150°C ambient temperature
•
Wide temperature range: - 40ºC to 150ºC
Supports daisy chain application
•
Unique Chip Identifier
Fitting to automotive applications
Two sensors in one package
•
•
Fully automotive qualified to AEC-Q100, grade 0
Small package: QFN 32 LD (7x7)
Applications
The AS5245 is ideal for applications with an angular travel range from a few degrees up to a full turn of 360º. The device is suitable for Automotive applications like
•
Throttle position sensors
•
Gas/brake pedal position sensing
•
Headlight position control
•
Contactless rotary position sensing
•
Front panel rotary switches
•
Replacement of potentiometer
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AS5245 −
General Description
Block Diagram
The functional blocks of this device for reference are shown below:
Figure 2:
AS5245 Block Diagram
9''9
9''9
LDO 3.3V
Hall Array
&
Frontend
Amplifier
6LQ
&RV
Mux
DSP
OTP
Register
AS5245
$QJ
0DJ
PWM
Interface
Absolute
Interface
(SSI)
Incremental
Interface
0DJ,1&Q
0DJ'(&Q
3:0
'2
&6Q
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3',2
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Note(s) and/or Footnote(s):
1. This block diagram presents only one die
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AS5245 −
Pin Assignments
Pin Assignments
Figure 3:
Pin Assignments (Top View)
DTest1_A_Bottom
DTest2_B_Top
DTest2_B_Bottom
NC
NC
Mode_Index_Top
Mode_Index_Bottom
VSS_Top
6
7
1
32 31 30 29 28 27 26 25
24
2
23
3
22
4
AS5245
21
5
20
19
18
8
9 10 11 12 13 14 15 16
17
VDD3V_Bottom
NC
NC
NC
NC
PWM_Top
PWM_Bottom
CSn_Top
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AS5245 −
Pin Assignments
Figure 4:
Pin Descriptions
Pin Name
Pin
Number
Pin Type Description
NC
Mode_Index
VSS
4, 5
6, 7
8, 9
For internal use. Must be left unconnected
Digital I/O pull-down
Select between slow (open, low: VSS) and fast (high) mode. Internal pull-down resistor. Hard wired connection to VDD or GND recommended.
Supply pin
Digital input pull-down
Negative Supply Voltage (GND)
OTP Programming Input and Data Input for Daisy
Chain mode.
Internal pull-down resistor (74k
Ω
).
Should be connected to VSS if programming is not used.
13
Digital input,
Schmitt-trigger input
Clock Input
of Synchronous Serial Interface;
Schmitt-Trigger input tri-state
Data Output
of Synchronous Serial Interface
Chip Select.
Active low. Schmitt-Trigger input, internal pull-up resistor (50k
Ω
) output
NC
NC
20, 21
22, 23
-
-
For internal use. Must be left unconnected
For internal use. Must be left unconnected
3V-Regulator Output for internal core, regulated from
VDD3V3 24, pin VDD5V. Connect to VDD5V for 3V supply voltage. Do not load externally.
VDD5V 26, 27 Supply pin Positive Supply Voltage, 3.0V to 5.5V
29
31
Digital output open drain
Digital output open drain
Magnet Field Magnitude Increase.
Active low.
Indicates a distance reduction between the magnet and the device surface.
Magnet Field Magnitude Decrease.
Active low.
Indicates a distance increase between the device and the magnet.
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Absolute Maximum R atings
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
DC supply voltage at pin VDD5V
DC supply voltage at pin
VDD3V3
-0.3 7 V
-0.3 5 V
Input pin voltage -0.3
Input current (latchup immunity) -100
Electrostatic discharge
Storage temperature
Body temperature
(Lead-free package)
-55
±2
7
100
150
Humidity non-condensing
Ambient temperature
Moisture sensitivity level
5
-40
3
85
150
V mA kV
ºC
%
ºC
Pins Prog, MagINCn, MagDECn, CLK, CSn
Norm: EIA/JESD78 Class II Level A
Norm: JESD22-A114E
Represents a maximum floor time of 168h
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AS5245 −
Electrical Characteristics
Electrical Characteristics
T
AMB
= -40 to 150ºC, V
DD
5V = 3.0-3.6V (3V operation)
VDD5V = 4.5-5.5V (5V operation) unless otherwise noted.
Figure 6:
Electrical Characteristics
Symbol Parameter Condition
Operating Conditions
T
AMB
I supp
Ambient temperature
Supply current (one die only)
V
V
V
V
DD
DD
DD
DD
5V
3V3
5V
3V3
Supply voltage at pin
V
DD
5V
Voltage regulator output voltage at pin V
DD
3V3
Supply voltage at pin
V
DD
5V
Supply voltage at pin
V
DD
3V3
5V Operation
3.3V Operation (pin V and V
DD
DD
5V
3V3 connected)
V
V
ON
OFF
Power-ON reset thresholds
ON voltage; 300mV typ. hysteresis
Power-ON reset thresholds
OFF voltage; 300mV typ. hysteresis
DC supply voltage 3.3V
(V
DD
3V3)
R
V
V
I
PROG
PROG
ProgOff programmed
R unprogrammed
Programming Conditions
Programming voltage
Voltage applied during programming
Programming voltage OFF level
Programming current
Programmed fuse resistance (log 1)
Unprogrammed fuse resistance (log 0)
Line must be discharged to this level
Current during programming
10
μ
A maximum current@100mV
2mA maximum current@100mV
Min Typ Max Unit
-40
16
150
21
ºC mA
4.5 5.0 5.5
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
1.08 1.9 2.6
V
100 mA
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Electrical Characteristics
Symbol Parameter Condition Min Typ Max Unit
V
IH
DC Characteristics CMOS Schmitt-Trigger Inputs: CLK, CSn (CSn = Internal Pull-Up)
High level input voltage Normal operation
0.7 *
V
DD
5V
V
IL
Low level input voltage
0.3 *
V
DD
5V
V
Ion
-V
Ioff
I
LEAK
Schmitt Trigger hysteresis 1
V
V
I
IL
IH
PROG
V
V
V
Input leakage current CLK only
Pull-up low level input current
CSn only, V
DD
5V: 5.0V
DC Characteristics CMOS / Program Input: PDIO
-1 1
μ
A
-30 -100
High level input voltage
0.7 *
V
DD
5V
V
DD
5V
V
High level input voltage
During programming,
Either with 3.3V or 5V supply
V
IL
Low level input voltage
0.3 *
V
DD
5V
V
I
I
IL
OZ
Low level input current
V
DD
5V: 5.5V
DC Characteristics CMOS Output Open Drain: MagINCn, MagDECn
Open drain leakage current
1
μ
A
V
OL
Low level output voltage
V
SS
+0.4
V
I
O
Output current
V
DD
5V: 4.5V
V
DD
5V: 3V
DC Characteristics CMOS Output: PWM
4
2 mA
V
OH
High level output voltage
V
DD
5V
– 0.5
V
V
OL
Low level output voltage
V
SS
+0.4
V
I
O
Output current
V
DD
5V: 4.5V
V
DD
5V: 3V
4
2 mA
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AS5245 −
Electrical Characteristics
Symbol
V
OH
V
OL
I
O
V
OH
V
OL
I
O
I
OZ
Parameter Condition Min Typ Max Unit
DC Characteristics CMOS Output: A, B, Index
High level output voltage
V
DD
5V
– 0.5
V
Low level output voltage
V
SS
+0.4
4
V
Output current
V
DD
5V: 4.5V
V
DD
5V: 3V
DC Characteristics Tri-State CMOS Output: DO
High level output voltage
V
DD
5V
– 0.5
2 mA
V
Low level output voltage
V
SS
+0.4
4
V
Output current
V
DD
5V: 4.5V
V
DD
5V: 3V
2 mA
Tri-state leakage current 1
μ
A
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AS5245 −
Electrical Characteristics
System Specifications
T
AMB
= -40 to 150ºC, V
DD
5V = 3.0 to 3.6V (3V operation)
V
DD
5V = 4.5 to 5.5V (5V operation) unless otherwise noted.
Figure 7:
Input Specification
Symbol Parameter Condition Min Typ Max Unit
RES Resolution
INL opt
Integral non-linearity
(optimum)
Maximum error with respect to the best line fit. Centered magnet without calibration, T
AMB
=25ºC.
INL temp
Integral non-linearity
(optimum)
Maximum error with respect to the best line fit. Centered magnet without calibration,
T
AMB
= -40 to 150ºC
Best line fit = (Err max
– Err min
) / 2
Over displacement tolerance with
6mm diameter magnet, without calibration, T
AMB
= -40 to 150ºC
DNL
Differential non-linearity
12bit, no missing codes t t
PwrUp delay f f
S
S
±0.5 deg
±0.9 deg
±1.4 deg
±0.044 deg
1 sigma, fast mode (MODE = 1) 0.06 open)
Fast mode (Mode = 1);
Until status bit OCF = 1
Power-up time
Slow mode (Mode = 0 or open);
Until OCF = 1
System propagation delay absolute output : delay of ADC, DSP and absolute interface
Fast mode (MODE = 1)
Slow mode (MODE = 0 or open)
T
AMB
= 25ºC, slow mode (MODE=0 or open)
Internal sampling rate for absolute output:
T
AMB
= -40 to 150ºC, slow mode
(MODE=0 or open)
0.03
20
80
96
384
2.48 2.61 2.74
2.35 2.61 2.87
Deg
RMS ms
μ s kHz
Internal sampling rate for absolute output
T
AMB
= 25ºC, fast mode (MODE = 1)
9.90 10.42 10.94
T
AMB
= -40 to 150ºC, fast mode
(MODE=1)
9.38 10.42 11.46 kHz
1 MHz
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AS5245 −
Electrical Characteristics
Figure 8:
Integral and Differential Non-Linearity Example
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Integral Non-Linearity (INL) is the maximum deviation between actual position and indicated position.
Differential Non-Linearity (DNL) is the maximum deviation of the step length from one position to the next.
Transition Noise (TN) is the repeatability of an indicated position.
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AS5245 −
Timing Characteristics
Timing Characteristics
T
AMB
= -40 to 150ºC, VDD5V = 3.0-3.6V (3V operation)
VDD5V = 4.5-5.5V (5V operation) unless otherwise noted.
Figure 9:
Timing Characteristics
Symbol
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
Start of data output
Time between falling edge of CSn and first falling edge of CLK
Rising edge of CLK shifts out one bit at a time
Data output valid
Data output tri-state
Pulse width of CSn
Read-out frequency
PWM frequency
Time between rising edge of CLK and data output valid
After the last bit DO changes back to “tri-state”
CSn =high; To initiate read-out of next angular position
Clock frequency to read out serial data
Pulse Width Modulation Output
Signal period = 4098
μ s ±10% at
T
AMB
= -40 to 150ºC
Minimum pulse width Position 0d; angle 0 degree
Maximum pulse width
Position 4098d; angle 359.91 degrees
Programming Conditions
Programming time per bit
Time to prog. a singe fuse bit
Refresh time per bit
LOAD frequency
100 ns
500 ns
500 ns
413 ns
100 ns
500 ns
220 244 268 Hz
0.90 1 1.10
3686 4096 4506
10 20
μ
μ
μ s s s
Time to charge the cap after t
PROG
1
μ s
Data can be loaded at n x 2
μ s 500
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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AS5245 −
Detailed Description
Detailed Description
The AS5245 is manufactured in a CMOS standard process and uses a spinning current Hall technology for sensing the magnetic field distribution across the surface of the chip. The integrated Hall elements are placed around the center of the device and deliver a voltage representation of the magnetic field at the surface of the IC.
Through Sigma-Delta Analog / Digital Conversion and Digital
Signal-Processing (DSP) algorithms, the AS5245 provides accurate high-resolution absolute angular position information. For this purpose, a Coordinate Rotation Digital
Computer (CORDIC) calculates the angle and the magnitude of the Hall array signals. The DSP is also used to provide digital information at the outputs MagINCn and MagDECn that indicate movements of the used magnet towards or away from the device’s surface. A small low cost diametrically magnetized
(two-pole) standard magnet provides the angular position information (see
The AS5245 senses the orientation of the magnetic field and calculates a 12-bit binary code. This code can be accessed via. a Synchronous Serial Interface (SSI). In addition, an absolute angular representation is given by a Pulse Width Modulated signal at pin 12 (PWM). This PWM signal output also allows the generation of a direct proportional analog voltage, by using an external Low-Pass-Filter. The AS5245 is tolerant to magnet misalignment and magnetic stray fields due to differential measurement technique and Hall sensor conditioning circuitry.
Figure 10:
Typical Arrangement of AS5245 and Magnet ams Datasheet
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Detailed Description
Mode_Index Pin
The Mode_Index pin activates or deactivates an internal filter that is used to reduce the analog output noise. Activating the filter (Mode pin = LOW or open) provides a reduced output noise of 0.03º rms. At the same time, the output delay is increased to 384
μ s. This mode is recommended for high precision, low speed applications.
Deactivating the filter (Mode pin = HIGH) reduces the output delay to 96
μ s and provides an output noise of 0.06º rms. This mode is recommended for higher speed applications.
Setting up the Mode pin affects the following parameters:
Figure 11:
Slow and Fast Mode Parameters
Parameter
Sampling rate
Transition noise
(1 sigma)
Output delay
Maximum speed @
4096 samples/rev
Maximum speed @
1024 samples/rev
Maximum speed @
256 samples/rev
Maximum speed @
64 samples/rev
Slow Mode (mode=low or open)
Fast Mode (mode=high, V
DD
=5V)
2.61 kHz (384 μs) 10.42 kHz (96
μ s)
≤ 0.03º rms ≤ 0.06º rms
384
μ s 96
μ s
38 rpm 153 rpm
153 rpm
610 rpm
2441 rpm
610 rpm
2441 rpm
9766 rpm
Note(s) and/or Footnote(s):
1. A change of the Mode during operation is not allowed. The setup must be constant during power up and during operation.
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AS5245 −
Detailed Description
Synchronous Serial Interface (SSI)
Figure 12:
Synchronous Serial Interface with Absolute Angular Position Data
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If CSn changes to logic low, Data Out (DO) will change from high impedance (tri-state) to logic high and the read-out will be initiated.
•
After a minimum time 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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AS5245 −
Detailed Description
Serial Data Contents
D11:D0
– Absolute angular position data (MSB is clocked out first).
OCF
– (Offset Compensation Finished). Logic high indicates the finished Offset Compensation Algorithm.
COF
– (Cordic Overflow). Logic high indicates an out of range error in the CORDIC part. When this bit is set, the data at D9:D0 is invalid. The absolute output maintains the last valid angular value. This alarm may be resolved by bringing the magnet within the X-Y-Z tolerance limits.
LIN
– (Linearity Alarm). Logic high indicates that the input field generates a critical output linearity. When this bit is set, the data at D9:D0 may still be used, but can contain invalid data. This warning may be resolved by bringing the magnet within the
X-Y-Z tolerance limits.
Even Parity
– Bit for transmission error detection of bits 1…17
(D11…D0, OCF, COF, LIN, MagINC, MagDEC). Placing the magnet above the chip, angular values increase in clockwise direction by default.
Data D11:D0 is valid, when the status bits have the following configurations:
Figure 13:
Status Bit Outputs
OCF COF
1 0
LIN
0
Mag INC
1
1
0
0
Note(s) and/or Footnote(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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AS5245 −
Detailed Description
Z-Axis Range Indication (Push Button Feature,
Red/Yellow/Green Indicator)
The AS5245 provides several options of detecting movement and distance of the magnet in the Z-direction. Signal indicators
MagINCn and MagDECn are available both as hardware pins
(pins #1 and 2) and as status bits in the serial data stream (see
Figure 12 ). Additionally, an OTP programming option is
available with bit MagCompEn that enables additional features:
In the default state, the status bits MagINC, MagDec and pins
MagINCn, MagDECn have the following function:
Figure 14:
Magnetic Field Strength Red-Yellow-Green Indicator (OTP Option)
Mag
INC
Status Bits
Mag
DEC
LIN
Hardware
Pins
Mag
INCn
Mag
DECn
OTP: MagCompEn = 1
(Red-Yellow-Green Programming Option)
Description
n/a
YELLOW range: magnetic field is ~ 25…45mT or range, but with slightly reduced accuracy.
RED range: magnetic field is ~<25mT or >~135mT. It is still recommended.
Not available All other combinations n/a
Note(s) and/or Footnote(s):
1. Pin 1 (MagINCn) and pin 2 (MagDECn) are active low via. open drain output and require an external pull-up resistor. If the magnetic field is in range, both outputs are turned OFF.
The two pins may also be combined with a single pull-up resistor. In this case, the signal is high when the magnetic field is in range. It is low in all other cases (see
Incremental Mode
The AS5245 has an internal interpolator block. This function is used if the input magnetic field is too fast and a code position is missing. In this case an interpolation is done.
With the OTP bits OutputMd0 and OutputMd1 a specific mode can be selected. For the available pre-programmed incremental versions (10bit and 12bit), these bits are set during test at
ams
.
These settings are permanent and can not be recovered.
A change of the incremental mode (WRITE command) during operation could cause problems. A power-ON-reset in between is recommended.
During operation in incremental mode it is recommended setting CSn = High, to disable the SSI-Interface.
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AS5245 −
Detailed Description
Figure 15:
Incremental Resolution
Mode Description
Default mode
Sync mode
AS5245 function
DTEST1_A
and
DTEST2_B
are not used. The
Mode_Index pin is used for selection of the decimation rate (low speed/high speed).
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
.
0 0
0 1 10 256
1 1
1/3
LSB
Figure 16:
Incremental Output
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The hysteresis trimming is done at the final test (factory trimming) and set to 4 LSB, related to a 12 bit number.
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AS5245 −
Detailed Description
Incremental Output Hysteresis.
To avoid flickering incremental outputs at a stationary magnet position, a hysteresis is introduced. In case of a rotational direction change, the incremental outputs have a hysteresis of
4 LSB. Regardless of the programmed incremental resolution, the hysteresis of 4 LSB always corresponds to the highest resolution of 12 bit. In absolute terms, the hysteresis is set to
0.35 degrees for all resolutions. For constant rotational directions, every magnet position change is indicated at the incremental outputs (see
). For example, if the magnet turns clockwise from position “x+3“ to “x+4“, the incremental output would also indicate this position accordingly. A change of the magnet’s rotational direction back to position “x+3“ means that the incremental output still remains unchanged for the duration of 4 LSB, until position “x+2“is reached. Following this direction, the incremental outputs will again be updated with every change of the magnet position.
Figure 17:
Hysteresis Window for Incremental Outputs
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Figure 18:
DTest1_A and DTest2_B
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AS5245 −
Detailed Description
Incremental Output Validity.
During power ON the incremental output is kept stable high until the offset compensation is finished and the CSn is low
(internal Pull Up) the first time. In quadrature mode
A = B = Index = high indicates an invalid output. If the interpolator recognizes a difference larger than 128 steps between two samples, it holds the last valid state. The interpolator synchronizes up again with the next valid difference. This avoids undefined output burst, e.g. if no magnet is present.
Sync Mode
This mode is used to synchronize the external electronic with the AS5245. In this mode, two signals are provided at the pins
DTEST1_A and DTEST2_B. By setting of Md0=1 and Md1=1 in the OTP register, the Sync mode will be activated.
Every rising edge at DTEST1_A indicates that new data in the device is available. With this signal it is possible to trigger an external customer Microcontroller (interrupt) and start the SSI readout. DTEST2_B indicates the phase of available data.
Sine/Cosine Mode
This mode can be enabled by setting the OTP Factory-bit FS2.
If this mode is activated, the 16 bit sinus and 16 bit cosines digital data of both channels will be switched out. Due to the high resolution of 16 bits of the data stream, an accurate calculation can be done externally. In this mode, the open drain outputs of DTEST1_A and DTEST2_B are switched to push-pull mode. At Pin MagDECn the clock impulse, at Pin MagINCn the
Enable pulse will be switched out. The pin PWM indicates, which phase of signal is being presented. The mode is not available in the default mode.
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AS5245 −
Detailed Description
Figure 19:
Daisy Chain Hardware Configuration
Daisy Chain Mode
The Daisy Chain mode allows connection of several AS5245s in series, while still keeping just one digital input for data transfer
(see “Data IN” in
Figure 19 ). This mode is accomplished by
connecting the data output (DO; pin 9) to the data input
(PDIO; pin 8) of the subsequent device. The serial data of all connected devices is read from the DO pin of the first device in the chain. The length of the serial bit stream increases with every connected device, it is n * (18+1) bits: n= number of devices. E.g. 38 bit for two devices, 57 bit for three devices, etc.
The last data bit of the first device (Parity) is followed by a dummy bit and the first data bit of the second device (D11), etc.
(see
).
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ams Datasheet
[v1-08] 2015-Jun-29
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AS5245 −
Detailed Description
Figure 20:
Daisy Chain Mode Data Transfer
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AS5245 −
Detailed Description
Figure 21:
PWM Output Signal
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3:
0,1
Pulse Width Modulation (PWM) Output
The AS5245 provides a pulse width modulated output (PWM), whose duty cycle is proportional to the measured angle. For angle position 0 to 4094:
(EQ1)
Position =
( t
ON t
ON
×
+ t
OFF
)
Examples:
1.
An angle position of 180º will generate a pulse width t
ON
= 2049
μ s and a pause t
OFF
of 2049
μ s resulting in
Position = 2048 after the calculation:
2049 * 4098 / (2049 + 2049) -1 = 2048
2.
An angle position of 359.8º will generate a pulse width t
ON
= 4095
μ s and a pause t
OFF
of 3
μ s resulting in
Position = 4094 after the calculation:
4095 * 4098 / (4095 + 3) -1 = 4094
Exception:
1.
An angle position of 359.9º will generate a pulse width t
ON
= 4097
μ s and a pause t
OFF
of 1
μ s 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.
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ams Datasheet
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AS5245 −
Detailed Description
Figure 22:
PWM Signal Parameters (Default mode)
Symbol
f
PWM
PW
MIN
Parameter
PWM frequency
MIN pulse width
Typ
244
1
PW
MAX
MAX pulse width
Changing the PWM Frequency
The PWM frequency of the AS5245 can be divided by two by setting a bit (PWMhalfEN) in the OTP register (see
Programming the AS5245 ). With PWMhalfEN = 0, the PWM timing is as shown
in
:
4096
Unit
Hz
μ s
μ s
Note
Signal period: 4097
μ s
•
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)
Symbol
f
PWM
PW
MIN
PW
MAX
Parameter
PWM frequency
MIN pulse width
MAX pulse width
Typ
122
2
8192
Unit
Hz
μ s
μ s
Note
•
Position 0d
•
Angle 0 deg
•
Position 4095d
•
Angle 359,91 deg
•
Position 0d
•
Angle 0 deg
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AS5245 −
Detailed Description
Analog Output
An analog output can be generated by averaging the PWM signal, using an external active or passive low pass filter. The analog output voltage is proportional to the angle:
0º= 0V; 360º = VDD5V.
Using this method, the AS5245 can be used as direct replacement of potentiometers.
Figure 24:
Simple 2nd Order Passive RC Low Pass Filter
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Figure 24 shows an example of a simple passive low pass filter
to generate the analog output.
(EQ2)
R1 R2
≥
4.7k
Ω ≥
1
μ
F 6V
R1 should be greater than or equal to 4.7kΩ to avoid loading of the PWM output. Larger values of Rx and Cx will provide better filtering and less ripple, but will also slow down the response time.
ams Datasheet
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Application Information
Page 26
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AS5245 −
Application Information
The benefits of AS5245 are as follows:
•
Complete system-ON-chip
•
Angle measurement with programmable range up to 360º
•
High reliability due to non-contact magnetic sensing
•
Ideal for applications in harsh environments
•
Robust system, tolerant to magnet misalignment, airgap variations, temperature variations and external magnetic fields
•
No calibration required
•
Building of redundancy systems with plausibility checks
Programming the AS5245
After power-ON, programming the AS5245 is enabled with the rising edge of CSn with PDIO = high and CLK = low.
The AS5245 programming is a one-time programming (OTP) method, based on poly silicon fuses. The advantage of this method is that a programming voltage of only 3.3V to 3.6V is required for programming.
The OTP consists of 52 bits, of which 23 bits are available for user programming. The remaining 29 bits contain factory settings and a unique chip identifier (Chip-ID).
A single OTP cell can be programmed only once. Per default, the cell is “0”; a programmed cell will contain a “1”. While it is not possible to reset a programmed bit from “1” to “0”, multiple
OTP writes are possible, as long as only unprogrammed “0”-bits are programmed to “1”.
Independent of the OTP programming, it is possible to overwrite the OTP register temporarily with an OTP write command at any time. This setting will be cleared and overwritten with the hard programmed OTP settings at each power-up sequence or by a LOAD operation. Use application note AN514X_10 to get more information about the programming options.
The OTP memory can be accessed in the following ways:
• Load Operation:
The Load operation reads the OTP fuses and loads the contents into the OTP register. A Load operation is automatically executed after each power-ON-reset.
• Write Operation:
The Write operation allows a temporary modification of the OTP register. It does not program the
OTP. This operation can be invoked multiple times and will remain set while the chip is supplied with power and while the OTP register is not modified with another Write or Load operation.
• Read Operation:
The Read operation reads the contents of the OTP register, for example to verify a Write command or to read the OTP memory after a Load command.
ams Datasheet
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AS5245 −
Application Information
• Program Operation:
The Program operation writes the contents of the OTP register permanently into the OTP
ROM.
• Analog Readback Operation:
The Analog Readback operation allows a quantifiable verification of the programming. For each programmed or unprogrammed bit, there is a representative analog value (in essence, a resistor value) that is read to verify whether a bit has been successfully programmed or not.
Zero Position Programming
Zero position programming is an OTP option that simplifies assembly of a system, as the magnet does not need to be manually adjusted to the mechanical zero position. Once the assembly is completed, the mechanical and electrical zero positions can be matched by software. Any position within a full turn can be defined as the permanent new zero position.
For zero position programming, the magnet is turned to the mechanical zero position (e.g. the “OFF”-position of a rotary switch) and the actual angular value is read.
This value is written into the OTP register bits Z35:Z46.
Note(s):
The zero position value may also be modified before programming, e.g. to program an electrical zero position that is 180º (half turn) from the mechanical zero position, just add
2048 to the value read at the mechanical zero position and program the new value into the OTP register.
ams Datasheet
[v1-08] 2015-Jun-29
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Figure 25:
OTP Bit Assignment
Bit Symbol
OTP Memory Assignment
AS5245 −
Application Information
Function
width
50 MagCompEn Alarm
49 pwmDIS Disable
48
47
Output Md0
Output Md1
Default, 10 bit inc, 12 bit inc
Sync mode
46 Z0
: : 12 bit Zero Position
35 Z11
34 CCW
33 RA0
Direction
29 RA4
Factory Bit
: :
18 FS11
17 ChipID0
16 ChipID1
: :
18 bit Chip ID
0 ChipID17
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AS5245 −
Application Information
User Selectable Settings
The AS5245 allows programming of the following user selectable options:
• PWMhalfEN_Indexwidth:
Setting this bit, the PWM pulse will be divided by 2, in case of quadrature incremental mode A/B/Index setting of Index impulse width from 1 LSB to 3LSB.
• MagCompEN:
The green/yellow mode can be enabled by setting of this bit.
• Output Md0:
Setting this bit enables sync- or 10bit incremental mode (see
). It is already set by
ams
.
• Output Md1:
Setting this bit enables sync- or 12bit incremental mode (see
• Z [11:0]:
Programmable Zero / Index Position
• CCW:
Counter Clockwise Bit ccw=0 – angular value increases in clockwise direction ccw=1 – angular value increases in counterclockwise direction
• RA [4:0]:
Redundant Address: an OTP bit location addressed by this address is always set to “1” independent of the corresponding original OTP bit setting
OTP Default Setting
The AS5245 can also be operated without programming. The default, un-programmed setting is:
• Output Md0, Output MD1:
00= Default mode
• Z0 to Z11:
00 = no programmed zero position
• CCW:
0 = clockwise operation
• RA4 to RA0
:0 = no OTP bit is selected
• MagCompEN:
1 = The green / yellow mode is enabled.
Redundancy
For a better programming reliability, a redundancy is implemented. This function can be used in cases where the programming of one bit fails.
With an address RA(4:0), one bit can be selected and programmed.
ams Datasheet
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A S 5 2 4 5 −
Application Information
Figure 26:
Redundancy Addressing
Address
PWMhalfEN
_Indexwidth
Mag
CompEN pwm
DIS
Output
Md0
Output
Md1
Z0 Z1 Z2 Z3 Z4 Z5 Z6 Z7 Z8 Z9 Z10 Z11 CCW
00000
00001
0
1
00010 0
00011 0
0
0
1
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 0
0 0 0 0 0 0 0 0 0 0 0 0
0
0
0
0
00100 0 0
1
0 0 0 0 0 0 0 0 0 0 0 0 0 0
00101 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
00110 0 0
00111 0 0
01000 0 0
01001 0 0
0 0
0 0
0 0
0 0 0 0 0 0 0 0 0 0
01010 0 0
01011
01100
0
0
0
0
0
0
0
0
01101
01110
01111
10000
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
1
0
0
1
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
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 0 0 0 0 0
1
0 0
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ams Datasheet
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A S 5 2 4 5 −
Application Information
Address
PWMhalfEN
_Indexwidth
Mag
CompEN pwm
DIS
Output
Md0
Output
Md1
Z0 Z1 Z2 Z3 Z4 Z5 Z6 Z7 Z8 Z9 Z10 Z11 CCW
10001
10010
10101
0
0
1
0
0
1
0
0
1
0
0
1
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
1
1 1 1 1 1 1 1 1 1 1 1 1 1 1 ams Datasheet
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Page 32
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AS5245 −
Application Information
Redundant Programming Option
In addition to the regular programming, a redundant programming option is available. This option allows that one selectable OTP bit can be set to “1” (programmed state) by writing the location of that bit into a 5-bit address decoder. This address can be stored in bits RA4…RA0 in the OTP user settings.
Example: setting RA4…0 to “00001” will select bit 51 = PWhalfEN_Indexwidth, “00010” selects bit 50 = MagCompEN, “10010” selects bit 34=CCW, etc.
Alignment Mode
The alignment mode simplifies centering the magnet over the center of the chip to gain maximum accuracy.
Alignment mode can be enabled with the falling edge of CSn while PDIO = logic high (see
Figure 27 ). The Data bits D11-D0
of the SSI change to a 12-bit displacement amplitude output.
A high value indicates large X or Y displacement, but also higher absolute magnetic field strength. The magnet is properly aligned, when the difference between highest and lowest value over one full turn is at a minimum.
Under normal conditions, a properly aligned magnet will result in a reading of less than 128 over a full turn.
The MagINCn and MagDECn indicators will be = 1 when the alignment mode reading is < 128. At the same time, both hardware pins MagINCn (#1) and MagDECn (#2) will be pulled to VSS. A properly aligned magnet will therefore produce a
MagINCn = MagDECn = 1 signal throughout a full 360º turn of the magnet.
Stronger magnets or short gaps between magnet and IC may show values larger than 128. These magnets are still properly aligned as long as the difference between highest and lowest value over one full turn is at a minimum.
The Alignment mode can be reset to normal operation by a power-ON-reset (disconnect / re-connect power supply) or by a falling edge on CSn with PDIO = low.
ams Datasheet
[v1-08] 2015-Jun-29
AS5245 −
Application Information
Figure 27:
Enabling the Alignment Mode
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Exiting Alignment Mode
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ams Datasheet
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AS5245 −
Application Information
Figure 29:
Connections for 5V / 3.3V Supply Voltages
3.3V / 5V Operation
The AS5245 operates either at 3.3V ±10% or at 5V ±10%. This is made possible by an internal 3.3V Low-Dropout (LDO) Voltage regulator. The internal supply voltage is always taken from the output of the LDO, meaning that the internal blocks are always operating at 3.3V.
For 3.3V operation, the LDO must be bypassed by connecting
VDD3V3 with VDD5V (see
).
For 5V operation, the 5V supply is connected to pin VDD5V, while VDD3V3 (LDO output) must be buffered by a 1...10
μ
F capacitor, which is supposed to be placed close to the supply pin (see
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
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A buffer capacitor of 100nF is recommended in both cases close to pin VDD5V. Note that pin VDD3V3 must always be buffered by a capacitor. It must not be left floating, as this may cause an instable internal 3.3V supply voltage, which may lead to larger than normal jitter of the measured angle.
ams Datasheet
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AS5245 −
Application Information
Choosing the Proper Magnet
Typically, the magnet should be 6mm in diameter and ≥ 2.5mm in height. Magnetic materials such as rare earth AlNiCo/SmCo5 or NdFeB are recommended. The magnetic field strength perpendicular to the die surface has to be in the range of
±45mT...± 75mT (peak).
The magnet’s field strength should be verified using a gauss-meter. The magnetic field B v
at a given distance, along a concentric circle with a radius of 1.1mm (R1), should be in the range of ±45mT...± 75mT (see
).
Figure 30:
Typical Magnet (6x3mm) and Magnetic Field Distribution
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AS5245 −
Application Information
Failure Diagnostics
The AS5245 also offers several diagnostic and failure detection features, which are discussed in detail further in the document.
Magnetic Field Strength Diagnosis
By Software:
The MagINC and MagDEC status bits will both be high when the magnetic field is out of range.
By Hardware:
Pins #1 (MagINCn) and #2 (MagDECn) are open-drain outputs and will both be turned ON (= low with external pull-up resistor) when the magnetic field is out of range. If only one of the outputs are low, the magnet is either moving towards the chip (MagINCn) or away from the chip
(MagDECn).
Power Supply Failure Detection
By Software:
If the power supply to the AS5245 is interrupted, the digital data read by the SSI will be all “0”s. Data is only valid, when bit OCF is high, hence a data stream with all “0”s is invalid. To ensure adequate low levels in the failure case, a pull-down resistor (~10k
Ω
) should be added between pin DIO and VSS at the receiving side.
By Hardware:
The MagINCn and MagDECn pins are open drain outputs and require external pull-up resistors. In normal operation, these pins are high ohmic and the outputs are high
(see
Figure 14 ). In a failure case, either when the magnetic field
is out of range of the power supply is missing, these outputs will become low. To ensure adequate low levels in case of a broken power supply to the AS5245, the pull-up resistors
(~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.
ams Datasheet
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AS5245 −
Application Information
Angular Output Tolerances
Accuracy
Accuracy is defined as the error between measured angle and actual angle. It is influenced by several factors:
•
The non-linearity of the analog-digital converters,
•
Internal gain and mismatch errors,
•
Non-linearity due to misalignment of the magnet.
As a sum of all these errors, the accuracy with centered magnet
= (Err max
- Err min
)/2 is specified as better than ±0.5 degrees
@ 25ºC (see
).
Misalignment of the magnet further reduces the accuracy.
Figure 32 shows an example of a 3D-graph displaying
non-linearity over XY-misalignment. The center of the square
XY-area corresponds to a centered magnet (see dot in the center of the graph). The X- and Y- axis extends to a misalignment of ±1mm in both directions. The total misalignment area of the graph covers a square of 2x2 mm
(79x79mil) with a step size of 100
μ m.
For each misalignment step, the measurement as shown in
Figure 34 is repeated and the accuracy (Err
max
- Err min
)/2 (e.g.
0.25º in
Figure 34 ) is entered as the Z-axis in the 3D-graph.
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Figure 31:
Example of Linearity Error Over XY Misalignment
AS5245 −
Application Information
Page 38
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6
5
4
°
3
2
1
0
-700
-1000
800
500
200
-100
x
-400
y
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.
ams Datasheet
[v1-08] 2015-Jun-29
AS5245 −
Application Information
Figure 32:
Example of Linearity Error Over 360º
0.5
0.4
0.3
0.2
0.1
0
-0.1
1
-0.2
-0.3
-0.4
-0.5
Err max transition noise
55 109 163 217 271 325 379 433 487 541 595 649 703 757 811 865 919 973
Err min
Transition Noise
Transition noise is defined as the jitter in the transition between two steps. Due to the nature of the measurement principle (Hall sensors + Preamplifier + ADC), there is always a certain degree of noise involved. This transition noise voltage results in an angular transition noise at the outputs. It is specified as
0.06 degrees rms (1 sigma)
1
in fast mode (pin MODE = high) and
0.03 degrees rms (1 sigma) in slow mode (pin MODE = low or open). This is the repeatability of an indicated angle at a given mechanical position. The transition noise has different implications on the type of output that is used:
• Absolute Output; SSI Interface:
The transition noise of the absolute output can be reduced by the user by implementing averaging of readings. An averaging of 4 readings will reduce the transition noise by 6dB or 50%, e.g. from 0.03º rms to 0.015º rms (1 sigma) in slow mode.
• PWM Interface:
If the PWM interface is used as an analog output by adding a low pass filter, the transition noise can be reduced by lowering the cutoff frequency of the filter.
If the PWM interface is used as a digital interface with a counter at the receiving side, the transition noise may again be reduced by averaging of readings.
• Incremental Mode:
In incremental mode, the transition noise influences the period, width and phase shift of the output signals A, B and Index. However, the algorithm used to generate the incremental outputs guarantees no missing or additional pulses even at high speeds (up to
30.000 rpm and higher).
1. Statistically, 1 sigma represents 68.27% of readings; 3 sigma represents 99.73% of readings.
ams Datasheet
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AS5245 −
Application Information
High Speed Operation
Sampling Rate.
The AS5245 samples the angular value at a rate of 2.61k (slow mode) or 10.42k (fast mode, selectable by pin
MODE) samples per second. Consequently, the absolute outputs are updated each 384μs (96μs in fast mode). At a stationary position of the magnet, the sampling rate creates no additional error.
Absolute Mode.
At a sampling rate of 2.6kHz/10.4kHz, the number of samples (n) per turn for a magnet rotating at high speed can be calculated by,
(EQ3)
n slowmode
=
60 rpm 384
μ s
(EQ4)
n fastmode
=
The upper speed limit in slow mode is ~6.000rpm and
~30.000rpm in fast mode. The only restriction at high speed is that there will be fewer samples per revolution as the speed increases (see
). Regardless of the rotational speed, the absolute angular value is always sampled at the highest resolution of 12 bit.
Incremental Mode.
Incremental encoders are usually required to produce no missing pulses up to several thousand rpms.
Therefore, the AS5245 has a built-in interpolator, which ensures that there are no missing pulses at the incremental outputs for rotational speeds of up to 30.000 rpm, even at the highest resolution of 10 bits (512 pulses per revolution).
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AS5245 −
Application Information
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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 96
μ s in fast mode and 384
μ s in slow mode.
Using the SSI interface for absolute data transmission, an additional delay must be considered, caused by the asynchronous sampling (0...1/fsample) and the time it takes the external control unit to read and process the angular data from the chip (maximum clock rate = 1MHz, number of bits per reading = 18).
Angular Error Caused by Propagation Delay.
A rotating magnet will cause an angular error caused by the output propagation delay. This error increases linearly with speed:
(EQ5)
e sampling
=
Where: esampling = angular error [º] rpm = rotating speed [rpm] prop.delay = propagation delay [seconds]
Note(s):
Since the propagation delay is known, it can be automatically compensated by the control unit processing the data from the AS5245.
Internal Timing Tolerance
The AS5245 does not require an external ceramic resonator or quartz. All internal clock timings for the AS5245 are generated by an ON-chip RC oscillator. This oscillator is factory trimmed to ±5% accuracy at room temperature (±10% over full temperature range). This tolerance influences the ADC sampling rate and the pulse width of the PWM output:
• Absolute Output; SSI Interface:
A new angular value is updated every 96
μ s (typ) in fast mode and every 384
μ s
(typ) in slow mode.
• PWM Output:
A new angular value is updated every 400
μ s
(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 t
ON
is used to measure the angle, the resulting value also has this timing tolerance. However, this tolerance can be cancelled by measuring both t
ON
and t
OFF
and calculating the angle from the duty cycle
(see
Pulse Width Modulation (PWM) Output ).
• Incremental Mode:
In incremental mode, the transition noise influences the period, width and phase shift of the output signals A, B and Index. However, the algorithm used to generate the incremental outputs guarantees no missing or additional pulses even at high speeds (up to
30.000 rpm and higher).
(EQ6)
Position =
( t
ON t
ON
×
+
4097 t
OFF
)
–
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AS5245 −
Application Information
Temperature
Magnetic Temperature Coefficient.
One of the major benefits of the AS5245 compared to linear Hall sensors is that it is much less sensitive to temperature. While linear Hall sensors require a compensation of the magnet’s temperature coefficients, the
AS5245 automatically compensates for the varying magnetic field strength over temperature. The magnet’s temperature drift does not need to be considered, as the AS5245 operates with magnetic field strengths from ±45…±75mT.
Example:
A NdFeB magnet has a field strength of 75mT @ -40ºC and a temperature coefficient of -0.12% per Kelvin. The temperature change is from -40º to +125º = 165K. The magnetic field change is: 165 x -0.12% = -19.8%, which corresponds to 75mT at -40ºC and 60mT at 125ºC.
The AS5245 can compensate for this temperature related field strength change automatically, no user adjustment is required.
Accuracy over Temperature
The influence of temperature in the absolute accuracy is very low. While the accuracy is less than or equal to ±0.5º at room temperature, it may increase to less then or equal to ±0.9º due to increasing noise at high temperatures.
Timing Tolerance over Temperature.
The internal RC oscillator is factory trimmed to ±5%. Over temperature, this tolerance may increase to ±10%. Generally, the timing tolerance has no influence in the accuracy or resolution of the system, as it is used mainly for internal clock generation. The only concern to the user is the width of the PWM output pulse, which relates directly to the timing tolerance of the internal oscillator. This influence, however, can be cancelled by measuring the complete PWM duty cycle instead of just the PWM pulse.
ams Datasheet
[v1-08] 2015-Jun-29
AS5245 −
Application Information
Figure 33:
Difference Between AS5245 and AS5045
AS5245 Differences to AS5045
All parameters are according to AS5045 data sheet except for the parameters shown below:
Building Block
Resolution
Ambient temperature range
Data length
Pins 1 and 2
Incremental encoder
Pin 6
Pin 12
Sampling frequency
Propagation delay
Transition noise
(rms; 1sigma)
OTP programming options
AS5245
12bits, 0.088º/step.
AS5045
12bits, 0.088º/step.
-40ºC to 150ºC -40ºC to 125ºC read: 18bits
(12bits data + 6 bits status)
OTP write: 18 bits
(12bits zero position + 6 bits mode selection)
MagINCn, MagDECn: same feature as
AS5045, additional OTP option for red-yellow-green magnetic range read: 18bits
(12bits data + 6 bits status)
OTP write: 18 bits
(12bits zero position + 6 bits mode selection)
MagINCn, MagDECn
Pin3 (DTest1_A); Pin 4 (DTest2_B);
Pin 6 (Mode_Index) 2x1024 ppr (12-bit)
2x256 ppr low-jitter (10-bit)
Not used
Pin 3: not used
Pin 4:not used
MODE_Index pin selects fast or slow mode in the default configuration. In case of incremental mode, the fast mode is selected and the pin is configured as output.
PWM output: frequency selectable by
OTP: 1
μ s / step, 4096 steps per revolution, f=244Hz
2
μ s/ step, 4096 steps per revolution, f=122Hz selectable by MODE input pin: 2.5kHz,
10,4kHz
384
μ s (slow mode)
96
μ s (fast mode)
0.03 degrees maximum (slow mode)
0.06 degrees maximum (fast mode)
PPTRIM; programming voltage
3.3V – 3.6V <70ºC; 3.5V – 3.6V >70ºC;
52-bit serial data protocol; CSn, PDIO and CLK
MODE_Index pin selects fast or slow mode in the default configuration.
PWM output: frequency selectable by
OTP: 1
μ s / step, 4096 steps per revolution, f=244Hz
2
μ s/ step, 4096 steps per revolution, f=122Hz selectable by MODE input pin:
2.5kHz, 10,4kHz
384
μ s (slow mode)
96
μ s (fast mode)
0.03 degrees maximum (slow mode)
0.06 degrees maximum (fast mode)
EasyZap; programming voltage
7.3V – 7.5V; Csn; Prog and CLK; 16-bit
(32-bit) serial data protocol;
ams Datasheet
[v1-08] 2015-Jun-29
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AS5245 −
Pack age Drawings & Mark ings
Package Drawings & Markings
Figure 34:
Package Drawing
The device is available in a QFN 32 (7mm x 7mm) package.
YYWWVZZ @
AS5245
17771-102
RoHS
Green
Symbol Min
L
Θ b
D
E e
A 0.80
A1 0
A2
A3
-
0.50
0º
0.23
Typ
0.90
0.02
0.65
0.20 REF
0.60
-
0.28
7.00 BSC
7.00 BSC
0.65 BSC
Max
1.00
0.05
1.00
0.75
14º
0.35
Symbol Min
D1
E1
D2
E2 aaa bbb ccc ddd eee fff
N
-
-
-
-
4.70
4.70
-
-
Typ
6.75 BSC
6.75 BSC
4.80
4.80
0.15
0.10
0.10
0.05
0.08
0.10
32
Max
-
-
-
-
4.90
4.90
-
-
Note(s) and/or Footnote(s):
1. Dimensions and tolerancing conform to ASME Y14.5M-1994.
2. All dimensions are in millimeters (angles in degrees).
3. Bilateral coplanarity zone applies to the exposed pad as well as the terminal.
4. Radius on terminal is optional.
5. N is the total number of terminals.
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ams Datasheet
[v1-08] 2015-Jun-29
AS5245 −
Package Drawings & Markings
Figure 35:
Package Code: @YYWWVZZ
YY
Last two digits of the year
WW
Manufacturing week
V
Plant identifier
ZZ
Assembly traceability code
@
Sublot identifier
ams Datasheet
[v1-08] 2015-Jun-29
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AS5245 −
Ordering & Contac t Information
Ordering & Contact Information
Figure 36:
Ordering Information
Ordering Code
AS5245-HMFP
AS5245-HMFM
Package
QFN 32 (7mm x 7mm)
Marking
AS5245
Delivery Form Delivery Quantity
Tape & Reel
4000
500
Buy our products or get free samples online at: www.ams.com/ICdirect
Technical Support is available at: www.ams.com/Technical-Support
Provide feedback about this document at: www.ams.com/Document-Feedback
For further information and requests, e-mail us at: [email protected]
For sales offices, distributors and representatives, please visit: www.ams.com/contact
Headquarters
ams AG
Tobelbaderstrasse 30
8141 Unterpremstaetten
Austria, Europe
Tel: +43 (0) 3136 500 0
Website: www.ams.com
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ams Datasheet
[v1-08] 2015-Jun-29
AS5245 −
RoHS Compliant & ams Green Statement
RoHS Compliant & ams Green
Statement
RoHS:
The term RoHS compliant means that ams AG products fully comply with current RoHS directives. Our semiconductor products do not contain any chemicals for all 6 substance categories, including the requirement that lead not exceed
0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, RoHS compliant products are suitable for use in specified lead-free processes.
ams Green (RoHS compliant and no Sb/Br):
ams Green defines that in addition to RoHS compliance, our products are free of Bromine (Br) and Antimony (Sb) based flame retardants
(Br or Sb do not exceed 0.1% by weight in homogeneous material).
Important Information:
The information provided in this statement represents ams AG knowledge and belief as of the date that it is provided. ams AG bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. ams AG has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. ams AG and ams AG suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.
ams Datasheet
[v1-08] 2015-Jun-29
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Copyrights & Disclaimer
AS5245 −
Copyrights & Disclaimer
Copyright ams AG, Tobelbader Strasse 30, 8141
Unterpremstaetten, Austria-Europe. Trademarks Registered. All rights reserved. The material herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner.
Devices sold by ams AG are covered by the warranty and patent indemnification provisions appearing in its General Terms of
Trade. ams AG makes no warranty, express, statutory, implied, or by description regarding the information set forth herein. ams AG reserves the right to change specifications and prices at any time and without notice. Therefore, prior to designing this product into a system, it is necessary to check with ams AG for current information. This product is intended for use in commercial applications. Applications requiring extended temperature range, unusual environmental requirements, or high reliability applications, such as military, medical life-support or life-sustaining equipment are specifically not recommended without additional processing by ams AG for each application. This product is provided by ams AG “AS IS” and any express or implied warranties, including, but not limited to the implied warranties of merchantability and fitness for a particular purpose are disclaimed.
ams AG shall not be liable to recipient or any third party for any damages, including but not limited to personal injury, property damage, loss of profits, loss of use, interruption of business or indirect, special, incidental or consequential damages, of any kind, in connection with or arising out of the furnishing, performance or use of the technical data herein. No obligation or liability to recipient or any third party shall arise or flow out of ams AG rendering of technical or other services.
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AS5245 −
Document Status
Document Status
Document Status
Product Preview
Preliminary Datasheet
Datasheet
Datasheet (discontinued)
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
ams Datasheet
[v1-08] 2015-Jun-29
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AS5245 −
Revision Information
Revision Information
Changes from 1.5 (2010-Jun-17) to current revision 1-08 (2015-Jun-29)
1.5 (2010-Jun-17) to 1-06 (2015-May-20)
Content of austriamicrosystems datasheet was converted to latest
ams
design
Added benefits to Figure 1
Updated Figure 10
Updated text under Programming the AS5245
Updated Figure 25
1-06 (2015-May-20) to 1-07 (2015-Jun-25)
Updated Figure 5
Updated Package Drawings & Markings section
1-07 (2015-Jun-25) to 1-08 (2015-Jun-29)
Updated Package Drawings & Markings section
Note(s) and/or Footnote(s):
1. Page and figure numbers for the previous version may differ from page and figure numbers in the current revision.
2. Correction of typographical errors is not explicitly mentioned.
Page
6
44
1
13
26
28
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ams Datasheet
[v1-08] 2015-Jun-29
AS5245 −
Content Guide
Content Guide
ams Datasheet
[v1-08] 2015-Jun-29
1 General Description
1 Key Benefits & Features
2 Applications
3 Block Diagram
4 Pin Assignments
6 Absolute Maximum Ratings
7 Electrical Characteristics
10 System Specifications
12 Timing Characteristics
13 Detailed Description
14 Mode_Index Pin
15 Synchronous Serial Interface (SSI)
16 Serial Data Contents
17 Z-Axis Range Indication (Push Button Feature, Red/Yellow/Green Indicator)
17 Incremental Mode
19 Incremental Output Hysteresis.
20 Incremental Output Validity.
20 Sync Mode
20 Sine/Cosine Mode
21 Daisy Chain Mode
23 Pulse Width Modulation (PWM) Output
24 Changing the PWM Frequency
25 Analog Output
26 Application Information
26 Programming the AS5245
27 Zero Position Programming
28 OTP Memory Assignment
29 User Selectable Settings
29 OTP Default Setting
29 Redundancy
32 Redundant Programming Option
32 Alignment Mode
34 3.3V / 5V Operation
35 Choosing the Proper Magnet
36 Failure Diagnostics
36 Magnetic Field Strength Diagnosis
36 Power Supply Failure Detection
37 Angular Output Tolerances
37 Accuracy
39 Transition Noise
40 High Speed Operation
41 Propagation Delays
41 Internal Timing Tolerance
42 Temperature
42 Accuracy over Temperature
43 AS5245 Differences to AS5045
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AS5245 −
Content Guide
44 Package Drawings & Markings
46 Ordering & Contact Information
47 RoHS Compliant & ams Green Statement
48 Copyrights & Disclaimer
49 Document Status
50 Revision Information
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ams Datasheet
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