AMSCO AS5140HASST

Data Sheet
AS5140H
10-Bit 360º Programmable Magnetic Rotary Encoder For High
A m b i e n t Te m p e r a t u r e s
1 General Description
2 Key Features
Contactless high resolution rotational position encoding over a
full turn of 360º
The AS5140H is a contactless magnetic rotary encoder for accurate
angular measurement over a full turn of 360º and over an extended
ambient temperature range of -40ºC to +150ºC.
Two digital 10-bit absolute outputs: Serial interface and Pulse
width modulated (PWM) output
It is a system-on-chip, combining integrated Hall elements, analog
front end and digital signal processing in a single device.
Three incremental output modes: Quadrature A/B and Index
output signal, Step / Direction and Index output signal, 3-phase
commutation for brushless DC motors
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.
User programmable zero / index position
The absolute angle measurement provides instant indication of the
magnet’s angular position with a resolution of 0.35º = 1024 positions
per revolution. This digital data is available as a serial bit stream and
as a PWM signal. Furthermore, a user-programmable incremental
output is available.
Failure detection mode for magnet placement monitoring and
loss of power supply
Rotational speeds up to 10.000 rpm
Pushbutton functionality detects movement of magnet in Z-axis
An internal voltage regulator allows the AS5140H to operate at either
3.3V or 5V supplies.
Serial read-out of multiple interconnected AS5140H devices
using Daisy Chain mode
The AS5140H is pin-compatible to the AS5040; however it uses lowvoltage OTP programming cells with additional programming
options.
Fully automotive qualified to AEC-Q100, grade 0
Wide ambient temperature range: -40ºC to +150ºC
3 Applications
The AS5140H is an ideal solution for automotive applications like
engine compartment sensors, transmission gearbox encoder, throttle
valve position control and for industrial applications like rotary
sensors in high temperature environment.
Figure 1. AS5140H IC Block Diagram
VDDV3V
VDD5V
MagINCn
MagDECn
LDO 3.3V
PWM
Interface
Sin
Hall Array
&
Frontend
Amplifier
AS5140H
Cos
PWM_LSB
Ang
DSP
Mag
Absolute
Interface
(SSI)
DO
CSn
CLK
OTP
Register
Programming
Parameters
Incremental
Interface
A_LSB_U
B_Dir_V
Index_W
Prog
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AS5140H
Data Sheet - C o n t e n t s
Contents
1 General Description
.................................................................................................................................................................. 1
2 Key Features
............................................................................................................................................................................ 1
3 Applications
.............................................................................................................................................................................. 1
4 Pin Assignments
....................................................................................................................................................................... 4
4.1 Pin Descriptions
................................................................................................................................................................................... 4
5 Absolute Maximum Ratings
6 Electrical Characteristics
...................................................................................................................................................... 6
.......................................................................................................................................................... 7
6.1 DC Characteristics for Digital Inputs and Outputs
6.2 Magnetic Input Specification
6.3 Electrical System Specifications
6.4 Programming Conditions
6.5 Timing Characteristics
7 Detailed Description
................................................................................................................................ 7
................................................................................................................................................................ 8
.......................................................................................................................................................... 8
...................................................................................................................................................................... 9
........................................................................................................................................................................ 10
............................................................................................................................................................... 12
7.1 10-bit Absolute Angular Position Output
............................................................................................................................................ 12
7.1.1 Synchronous Serial Interface (SSI) ........................................................................................................................................... 12
7.1.2 Daisy Chain Mode ..................................................................................................................................................................... 14
7.2 Incremental Outputs
........................................................................................................................................................................... 15
7.2.1 Quadrature A/B Output (Quad A/B Mode) ................................................................................................................................. 15
7.2.2 LSB Output (Step/Direction Mode) ............................................................................................................................................ 15
7.2.3 Incremental Output Hysteresis .................................................................................................................................................. 16
7.3 Pulse Width Modulation (PWM) Output
7.4 Analog Output
7.5 Brushless DC Motor Commutation Mode
7.6 Programming the AS5140H
7.6.1
7.6.2
7.6.3
7.6.4
7.6.5
7.6.6
7.6.7
............................................................................................................................................. 16
.................................................................................................................................................................................... 17
........................................................................................................................................... 18
............................................................................................................................................................... 19
OTP Memory Assignment .......................................................................................................................................................... 19
User Selectable Settings ........................................................................................................................................................... 20
OTP Default Setting ................................................................................................................................................................... 20
Redundant Programming Option ............................................................................................................................................... 20
OTP Register Entry and Exit Condition ..................................................................................................................................... 20
Incremental Mode Programming ............................................................................................................................................... 21
Zero Position Programming ....................................................................................................................................................... 22
7.7 Alignment Mode
................................................................................................................................................................................. 22
7.8 3.3V / 5V Operation
............................................................................................................................................................................ 23
7.9 Choosing the Proper Magnet
............................................................................................................................................................. 24
7.9.1 Physical Placement of the Magnet ............................................................................................................................................ 24
7.10 Simulation Modeling
......................................................................................................................................................................... 26
7.11 Failure Diagnostics
........................................................................................................................................................................... 27
7.11.1 Magnetic Field Strength Diagnosis .......................................................................................................................................... 27
7.11.2 Power Supply Failure Detection .............................................................................................................................................. 27
7.12 Angular Output Tolerances
7.12.1
7.12.2
7.12.3
7.12.4
7.12.5
............................................................................................................................................................... 27
Accuracy .................................................................................................................................................................................. 27
Transition Noise ....................................................................................................................................................................... 29
High Speed Operation ............................................................................................................................................................. 29
Propagation Delays ................................................................................................................................................................. 30
Internal Timing Tolerance ........................................................................................................................................................ 30
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AS5140H
Data Sheet - C o n t e n t s
7.12.6 Temperature ............................................................................................................................................................................ 31
8 Application Information
........................................................................................................................................................... 32
8.1 AS5140H Differences to AS5040
....................................................................................................................................................... 32
9 Package Drawings and Markings
........................................................................................................................................... 33
9.1 Recommended PCB Footprint
........................................................................................................................................................... 34
10 Ordering Information
............................................................................................................................................................. 36
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AS5140H
Data Sheet - P i n A s s i g n m e n t s
4 Pin Assignments
Figure 2. Pin Assignments (Top View)
1
16
VDD5V
MagDECn
2
15
VDD3V3
A_LSB_U
3
14
NC
B_Dir_V
4
13
NC
12
PWM_LSB
11
CSn
NC
Index_W
5
6
AS5140H
MagINCn
VSS
7
10
CLK
Prog
8
9
DO
4.1 Pin Descriptions
The following table 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 2).
Table 1. Pin Descriptions
Pin Name
Pin Number
Description
MagINCn
1
Magnet Field Magnitude Increase. Active low. Indicates a distance reduction between the
magnet and the device surface.
MagDECn
2
Magnet Field Magnitude Decrease. Active low. Indicates a distance increase between the
device and the magnet.
A_LSB_U
3
Mode1.x: Quadrature A channel
Mode2.x: Least Significant Bit
Mode3.x: U signal (phase1)
B_Dir_V
4
Mode1.x: Quadrature B channel quarter period shift to channel A
Mode2.x: Direction of Rotation
Mode3.x: V signal (phase2)
NC
5
For internal use. Must be left unconnected.
Index_ W
6
Mode1.x and Mode2.x: Index signal indicates the absolute zero position
Mode3.x: W signal (phase3)
VSS
7
Negative Supply Voltage (GND).
Prog
8
OTP Programming Input and Data Input for Daisy Chain mode. Internal pull-down
resistor (~74kΩ). May be connected to VSS if programming is not used.
DO
9
Data Output of Synchronous Serial Interface.
CLK
10
SSI Clock Input. Schmitt-Trigger input.
CSn
11
Chip Select. Active low; Schmitt-Trigger input, internal pull-up resistor (~50kΩ) connect to
VSS in incremental mode (see Incremental Power-up Lock Option on page 16)
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AS5140H
Data Sheet - P i n A s s i g n m e n t s
Table 1. Pin Descriptions
Pin Name
Pin Number
Description
PWM_LSB
12
Pulse Width Modulation of approx. 1kHz; LSB in Mode3.x
NC
13
For internal use. Must be left unconnected.
NC
14
For internal use. Must be left unconnected.
VDD3V3
15
3V-Regulator Output (see Figure 17)
VDD5V
16
Positive Supply Voltage 5V
Pins 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 contact-less push-button functionality. Pins 3, 4 and 6 are the incremental pulse output pins. The functionality of
these pins can be configured through programming the one-time programmable (OTP) register:
Table 2. Pin Assignment for Different Incremental Output Modes
Output Mode
Pin 3
Pin 4
Pin 6
Pin 12
1.x: Quadrature
A
B
Index
PWM
2.x: Step/direction
LSB
Direction
Index
PWM
3.x: Commutation
U
V
W
LSB
Mode 1.x: Quadrature A/B Output
Represents the default quadrature A/B signal mode.
Mode 2.x: Step / Direction Output
Configures pin 3 to deliver up to 512 pulses (up to 1024 state changes) per revolution. It is equivalent to the LSB (least significant bit) of the
absolute position value. Pin 4 provides the information of the rotational direction.
Note: Both modes (mode 1.x and mode 2.x) provide an index signal (1 pulse/revolution) with an adjustable width of one LSB or three LSB’s.
Mode 3.x: Brushless DC Motor Commutation Mode
In addition to the absolute encoder output over the SSI interface, this mode provides commutation signals for brushless DC motors with either
one pole pair or two pole pair rotors. The commutation signals are usually provided by 3 discrete Hall switches, which are no longer required, as
the AS5140H can fulfill two tasks in parallel: absolute encoder + BLDC motor commutation. In this mode,
- Pin 12 provides the LSB output instead of the PWM (Pulse-Width-Modulation) signal.
- Pin 8 (Prog) is also used to program the different incremental interface modes, the incremental resolution and the zero position into the
OTP (see page 21). This pin is also used as digital input to shift serial data through the device in Daisy Chain configuration, (see page 14).
- Pin 11 Chip Select (CSn; active low) selects a device within a network of AS5140H encoders 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 page
22) and programming mode (see page 19).
- Pin 12 allows a single wire output of the 10-bit absolute position value. The value is encoded into a pulse width modulated signal with 1µs
pulse width per step (1µs to 1024µs over a full turn). By using an external low pass filter, the digital PWM signal is converted into an analog voltage, allowing a direct replacement of potentiometers.
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AS5140H
Data Sheet - A b s o l u t e M a x i m u m R a t i n g s
5 Absolute Maximum Ratings
Stresses beyond those listed in Table 3 may cause permanent damage to the device. These are stress ratings only, and functional operation of
the device at these or any other conditions beyond those indicated in Electrical Characteristics on page 7 is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect device reliability.
Table 3. Absolute Maximum Ratings
Parameter
Min
Max
Units
DC supply voltage at pin VDD5V
-0.3
7
V
DC supply voltage at pin VDD3V3
-0.3
5
V
Comments
Input pin voltage
-0.3
7
V
Pins Prog, MagINCn, MagDECn, CLK, CSn
Input current (latchup immunity)
-100
100
mA
Norm: JEDEC 78
±2
kV
Norm: MIL 883 E method 3015
+150
ºC
260
ºC
Electrostatic discharge
Storage temperature
-55
Body temperature (Lead-free package)
Humidity non-condensing
5
85
%
Ambient temperature
-40
150
ºC
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Lead finish 100% Sn “matte tin”
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AS5140H
Data Sheet - E l e c t r i c a l C h a r a c t e r i s t i c s
6 Electrical Characteristics
TAMB = -40 to 150ºC, VDD5V = 3.0-3.6V (3V operation) VDD5V = 4.5-5.5V (5V operation), unless otherwise noted.
Table 4. Operating Conditions
Symbol
Parameter
Isupp
Supply current
VDD5V
External supply voltage at pin VDD5V
Conditions
Min
Typ
Max
Units
16
21
mA
4.5
5.0
5.5
V
3.0
3.3
3.6
V
VDD3V3
Internal regulator output voltage at pin
VDD3V3
5V operation
VDD5V
3.3V operation
(pins VDD5V and VDD3V3 connected)
3.0
3.3
3.6
V
VDD3V3
External supply voltage at pin
VDD5V,VDD3V3
3.0
3.3
3.6
V
tpwrup3
External VDD3V3 supply voltage rise
time at power-up
10%-90% level in 3.3V mode (pins VDD5V
and VDD3V3 connected)
1
150
µs
Max
Units
6.1 DC Characteristics for Digital Inputs and Outputs
Table 5. CMOS Schmitt-Trigger Inputs: CLK, CSn (CSn = Internal Pull-up)
Symbol
Parameter
Conditions
Min
Typ
VIH
High level input voltage
Normal operation
0.7 *
VDD5V
VIL
Low level input voltage
VIon - VIoff
Schmitt Trigger hysteresis
ILEAK
Input leakage current
CLK only
-1
1
IiL
Pull-up low level input current
CSn only, VDD5V:5.0V
-30
-100
Conditions
Min
V
0.3 *
VDD5V
1
V
V
µA
Table 6. CMOS / Program Input: Prog
Symbol
Parameter
VIH
High level input voltage
VPROG
High level input voltage
VIL
Low level input voltage
IiL
Pull-down high level input current
Typ
Max
Units
5
V
Refer to Programming
Conditions on page 9
V
0.7 *
VDD5V
During programming
VDD5V:5.5V
0.3 *
VDD5V
V
100
µA
Max
Units
VSS+0.4
V
Table 7. CMOS Output Open Drain: MagINCn, MagDECn
Symbol
Parameter
VOL
Low level output voltage
IO
Output current
IOZ
Open drain leakage current
Conditions
Min
Typ
VDD5V:4.5V
4
VDD5V:3V
2
mA
1
µA
Max
Units
Table 8. CMOS Output: A, B, Index, PWM
Symbol
VOH
Parameter
Conditions
High level output voltage
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Min
VDD5V0.5
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Typ
V
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AS5140H
Data Sheet - E l e c t r i c a l C h a r a c t e r i s t i c s
Table 8. CMOS Output: A, B, Index, PWM (Continued)
Symbol
Parameter
VOL
Low level output voltage
IO
Output current
Conditions
Min
Typ
Max
Units
VSS+0.4
V
VDD5V:4.5V
4
VDD5V:3V
2
mA
Table 9. Tristate CMOS Output: DO
Symbol
Parameter
VOH
High level output voltage
VOL
Low level output voltage
IO
Output current
IOZ
Tri-state leakage current
Conditions
Min
Typ
Max
VDD5V0.5
Units
V
VSS+0.4
VDD5V:4.5V
4
VDD5V:3V
2
V
mA
1
µA
Max
Units
6.2 Magnetic Input Specification
Table 10. Electrical Characteristics
Symbol
Parameter
Conditions
Min
Typ
4
6
Magnetic Input Specification (Two-pole cylindrical diametrically magnetized source)
dmag
Diameter
tmag
Thickness
Bpk
Magnetic input field amplitude
Required vertical component of the
magnetic field strength on the die’s surface,
measured along a concentric circle with a
radius of 1.1mm
Boff
Magnetic offset
Field non-linearity
Disp
mm
2.5
75
mT
Constant magnetic stray field
±10
mT
Including offset gradient
5
%
Absolute mode: 600 rpm @ readout of 1024
positions (see Table 19)
10
Hz
Incremental mode: no missing pulses at
rotational speeds of up to 10.000 rpm (see
Table 19)
166
Hz
Max. X-Y offset between defined IC
package center and magnet axis (see
Figure 19)
0.25
Max. X-Y offset between chip center and
magnet axis
0.485
Chip placement tolerance
Placement tolerance of chip within IC
package (see Figure 21)
±0.235
Recommended magnet material and
temperature drift
NdFeB (Neodymium Iron Boron)
-0.12
SmCo (Samarium Cobalt)
-0.035
fmag_abs
fmag_inc
Recommended magnet: Ø 6mm x 2.5mm
for cylindrical magnets
Input frequency (rotational speed of
magnet)
Displacement Radius
45
mm
mm
%/K
6.3 Electrical System Specifications
Table 11. Electrical System Specifications
Symbol
Parameter
RES
Resolution
1
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Conditions
0.352 deg
Revision 1.4
Min
Typ
Max
Units
10
bit
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AS5140H
Data Sheet - E l e c t r i c a l C h a r a c t e r i s t i c s
Table 11. Electrical System Specifications (Continued)
Symbol
Parameter
Conditions
Min
7 bit
LSB
Max
Units
2.813
Adjustable resolution only available for
incremental output modes;
Least significant bit, minimum step
8 bit
9 bit
1.406
deg
0.703
10 bit
0.352
2
Maximum error with respect to the best line
fit.
Verified at optimum magnet placement,
TAMB =25ºC
±0.5
deg
Integral non-linearity (optimum)
Maximum error with respect to the best line
fit.
Verified at optimum magnet placement,
TAMB = -40 to +150ºC
±0.9
deg
INL
Integral non-linearity
Best line fit = (Errmax – Errmin) / 2
Over displacement tolerance with 6mm
diameter magnet, TAMB = -40 to +150ºC
(see Figure 3)
±1.4
deg
DNL
Differential non-linearity
10bit, no missing codes
±0.176
deg
TN
Transition noise
RMS equivalent to 1 sigma
0.12
Deg
RMS
Hyst
Hysteresis
Von
Power-on reset thresholds
On voltage; 300mV typ. hysteresis
Voff
Power-on reset thresholds
Off voltage; 300mV typ. hysteresis
tPwrUp
Power-up time
Until offset compensation finished
50
ms
tdelay
System propagation delay
absolute output
Includes delay of ADC and DSP
48
µs
System propagation delay
incremental output
Calculation over two samples
192
µs
INLopt
INLtemp
1.
2.
3.
4.
Typ
Integral non-linearity (optimum)
3
4
Incremental modes only
0.704
deg
1.37
2.2
2.9
1.08
1.9
2.6
DC supply voltage 3.3V (VDD3V3)
V
Internal sampling rate, TAMB = 25ºC
9.90
10.42
10.94
fS
Sampling rate for absolute output
Internal sampling rate, TAMB = -40 to
+150ºC
9.38
10.42
11.46
CLK
Read-out frequency
Max. clock frequency to read out serial data
kHz
1
MHz
Digital Interface
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.
6.4 Programming Conditions
TAMB = -40 to 150ºC, VDD5V = 3.0-3.6V (3V operation) VDD5V = 4.5-5.5V (5V operation), unless otherwise noted.
Table 12. Programming Conditions
Symbol
Parameter
Conditions
Min
Typ
Max
Units
VPROG
Programming voltage
Voltage applied during programming
3.0
3.3
3.6
V
VProgOff
Programming voltage off level
Line must be discharged to this level
0
1
V
IPROG
Programming current
Current during programming
100
mA
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AS5140H
Data Sheet - E l e c t r i c a l C h a r a c t e r i s t i c s
Table 12. Programming Conditions (Continued)
Symbol
Parameter
Conditions
Min
Rprogrammed
Programmed fuse resistance (log 1)
10µA max. current @ 100mV
Max
Units
100k
∞
Ω
2mA max. current @ 100mV
50
100
Ω
Programming time per bit
Time to prog. a singe fuse bit
10
20
µs
tCHARGE
Refresh time per bit
Time to charge the cap after tPROG
1
fLOAD
LOAD frequency
Data can be loaded at n*2µs
500
kHz
fREAD
READ frequency
Read the data from the latch
2.5
MHz
fWRITE
WRITE frequency
Write the data to the latch
2.5
MHz
Max
Units
100
ns
Runprogrammed Unprogrammed fuse resistance (log 0)
tPROG
Typ
µs
6.5 Timing Characteristics
TAMB = -40 to +150ºC, VDD5V = 3.0-3.6V (3V operation) VDD5V = 4.5-5.5V (5V operation), unless otherwise noted.
Table 13. Synchronous Serial Interface (SSI)
Symbol
Parameter
Conditions
Min
Typ
tDO active
Data output activated (logic high)
Time between falling edge of CSn and
data output activated
tCLK FE
First data shifted to output register
Time between falling edge of CSn and
first falling edge of CLK
500
ns
TCLK/2
Start of data output
Rising edge of CLK shifts out one bit at a
time
500
ns
tDO valid
Data output valid
Time between rising edge of CLK and
data output valid
413
ns
tDO tristate
Data output tristate
After the last bit DO changes back to
“tristate”
100
ns
tCSn
Pulse width of CSn
CSn =high; To initiate read-out of next
angular position
500
fCLK
Read-out frequency
Clock frequency to read out serial data
>0
Conditions
Min
Signal period = 1025µs ±5% at Tamb =
25ºC
ns
1
MHz
Typ
Max
Units
0.927
0.976
1.024
Signal period =1025µs ±10% at Tamb =
-40 to +150ºC
0.878
0.976
1.074
Table 14. Pulse Width Modulation Output
Symbol
fPWM
Parameter
PWM frequency
kHz
PWMIN
Minimum pulse width
Position 0d; angle 0 degree
0.90
1
1.10
µs
PWMAX
Maximum pulse width
Position 1023d; angle 359.65 degree
922
1024
1126
µs
Min
Typ
Max
Units
Table 15. Incremental Outputs
Symbol
Parameter
Conditions
tIncremental
Incremental outputs valid after power-up
Time between first falling edge of CSn
after power-up and valid incremental
outputs
500
ns
tDir valid
Directional indication valid
Time between rising or falling edge of
LSB output and valid directional
indication
500
ns
outputs valid
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AS5140H
Data Sheet - E l e c t r i c a l C h a r a c t e r i s t i c s
Figure 3. Integral and Differential Non-Linearity Example (exaggerated curve)
1023
α 10bit code
1023
Actual curve
2
TN
DNL+1LSB
1
0
512
Ideal curve
INL
0.35°
512
0
0°
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180°
Revision 1.4
360 °
α [degrees]
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AS5140H
Data Sheet - D e t a i l e d D e s c r i p t i o n
7 Detailed Description
The AS5140H 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 AS5140H provides accurate high-resolution absolute angular position information. For this purpose, a Coordinate Rotation
Digital Computer (CORDIC) calculates the angle and the magnitude of the Hall array signals. The DSP is also used to provide digital information
at the outputs MagINCn and MagDECn that indicate movements of the used magnet towards or away from the device’s surface. A small low cost
diametrically magnetized (two-pole) standard magnet provides the angular position information (see Figure 18).
The AS5140H senses the orientation of the magnetic field and calculates a 10-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).
Simultaneously, the device also provides incremental output signals. The various incremental output modes can be selected by programming the
OTP mode register bits (see Table 20). As long as no programming voltage is applied to pin Prog, the new setting may be overwritten at any time
and will be reset to default when power is turned off. To make the setting permanent, the OTP register must be programmed. The default setting
is a quadrature A/B mode including the Index signal with a pulse width of 1 LSB. The Index signal is logic high at the user programmable zero
position.
The AS5140H is tolerant to magnet misalignment and magnetic stray fields due to differential measurement technique and Hall sensor
conditioning circuitry.
Figure 4. Typical Arrangement of AS5140H and Magnet
7.1 10-bit Absolute Angular Position Output
7.1.1
Synchronous Serial Interface (SSI)
If CSn changes to logic low, Data Out (DO) will change from high impedance (tri-state) to logic high and the read-out will be initiated.
After a minimum time tCLK FE, data is latched into the output shift register with the first falling edge of CLK.
Each subsequent rising CLK edge shifts out one bit of data.
The serial word contains 16 bits; the first 10 bits are the angular information D[9:0], 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 log “high” pulse at CSn with a minimum duration of tCSn.
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AS5140H
Data Sheet - D e t a i l e d D e s c r i p t i o n
Figure 5. Synchronous Serial Interface with Absolute Angular Position Data
CSn
tCLK FE
tCSn
TCLK/2
tCLK FE
8
1
CLK
D9
DO
tDO active
D8
D7
tDO valid
D5
D6
D4
D3
1
16
D2
D1
D0
OCF COF
Angular Position Data
LIN
Mag Mag Even
INC DEC PAR
Status Bits
D9
tDO Tristate
Data Content
D9:D0 – Absolute angular position data (MSB is clocked out first).
OCF – (Offset Compensation Finished). Logic high indicates the finished Offset Compensation Algorithm. For fast startup, this bit may be polled
by the external microcontroller. As soon as this bit is set, the AS5140H has completed the startup and the data is valid (see Table 17).
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.
MagINCn – (Magnitude Increase) becomes HIGH, when the magnet is pushed towards the IC, thus increasing the magnetic field strength.
MagDECn – (Magnitude Decrease) becomes HIGH, when the magnet is pulled away from the IC, thus decreasing the magnetic field strength.
Signal “HIGH” for both MagINCn and MagDECn indicate a magnetic field that is out of the allowed range (see Table 16).
Table 16. Magnetic Magnitude Variation Indicator
MagINCn
MagDECn
Description
0
0
No distance change
Magnetic Input Field OK (in range)
0
1
Distance increase: Pull-function. This state is dynamic, it is only active while the magnet
is moving away from the chip in Z-axis.
1
0
Distance decrease: Push- function. This state is dynamic, it is only active while the
magnet is moving towards the chip in Z.-axis.
1
1
Magnetic Input Field invalid – out of range: Too large, Too small (missing magnet).
Note: Pins 1 and 2 (MagINCn, MagDECn) are open drain outputs and require external pull-up resistors. 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 Table 16).
Even Parity – A bit for transmission error detection of bits 1to 15 (D9 to D0, OCF, COF, LIN, MagINCn, MagDECn).
The absolute angular output is always set to a resolution of 10 bit. Placing the magnet above the chip, angular values increase in clockwise
direction by default. Data D9:D0 is valid, when the status bits have the following configurations:
Table 17. Status Bit Outputs
OCF
1
COF
0
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LIN
0
MagINCn
MagDECn
0
0
0
1
1
0
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Parity
even checksum of bits 1:15
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Data Sheet - D e t a i l e d D e s c r i p t i o n
The absolute angular position is sampled at a rate of 10kHz (0.1ms). This allows reading of all 1024 positions per 360 degrees within 0.1
seconds = 9.76Hz (~10Hz) without skipping any position. Multiplying 10Hz by 60, results the corresponding maximum rotational speed of 600
rpm. Readout of every second angular position allows for rotational speeds of up to 1200 rpm.
Consequently, increasing the rotational speed reduces the number of absolute angular positions per revolution (see Table 21). Regardless of the
rotational speed or the number of positions to be read out, the absolute angular value is always given at the highest resolution of 10 bit.
The incremental outputs are not affected by rotational speed restrictions due to the implemented interpolator. The incremental output signals
may be used for high-speed applications with rotational speeds of up to 10.000 rpm without missing pulses.
7.1.2
Daisy Chain Mode
The Daisy Chain mode allows connection of several AS5140H’s in series, while still keeping just one digital input for data transfer (see “Data IN”
in Figure 6 below). This mode is accomplished by connecting the data output (DO; pin 9) to the data input (Prog; 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 Prog pin of the last device in the chain should
be connected to VSS. The length of the serial bit stream increases with every connected device. It is,
n * (16+1) bits
(EQ 1)
For example, 34 bit for two devices, 51 bit for three devices, etc.
The last data bit of the first device (Parity) is followed by a logic low bit and the first data bit of the second device (D9), etc. (see Figure 7).
Figure 6. Daisy Chain Hardware Configuration
AS5140H
AS5140H
µC
st
2
1 Device
Data IN
Prog
DO
DO
AS5140H
last Device
Device
Prog
CSn
CLK
CSn
nd
DO
CLK
CSn
Prog
CLK
CLK
CSn
Figure 7. Daisy Chain Mode Data Transfer
CSn
TCLK/2
tCLK FE
1
CLK
D9
DO
tDO active
8
D8
D7
tDO valid
D6
D5
D4
D3
16
D2
D1
D0
OCF COF
Angular Position Data
Mag Mag Even
INC DEC PAR
Status Bits
st
1 Device
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LIN
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D
1
D9
2
3
D8
D7
Angular Position Data
nd
2 Device
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Data Sheet - D e t a i l e d D e s c r i p t i o n
Programming Daisy Chained Devices. In Daisy Chain mode, the Prog pin is connected directly to the DO pin of the subsequent device in
the chain (see Figure 6). During programming (see Programming the AS5140H on page 19), a programming voltage of 7.5V must be applied to
pin Prog. This voltage level exceeds the limits for pin DO, so one of the following precautions must be made during programming:
Open the connection DO → Prog during programming, (or)
Add a Schottky diode between DO and Prog (Anode = DO, Cathode = Prog)
Due to the parallel connection of CLK and CSn, all connected devices may be programmed simultaneously.
7.2 Incremental Outputs
Three different incremental output modes are possible with quadrature A/B being the default mode. Figure 8 shows the two-channel quadrature
as well as the step / direction incremental signal (LSB) and the direction bit in clockwise (CW) and counter-clockwise (CCW) direction.
7.2.1
Quadrature A/B Output (Quad A/B Mode)
The phase shift between channel A and B indicates the direction of the magnet movement. Channel A leads channel B at a clockwise rotation of
the magnet (top view) by 90 electrical degrees. Channel B leads channel A at a counter-clockwise rotation.
Figure 8. Incremental Output Modes
Mechanical
Zero Position
Quad A/B-Mode
Mechanical
Zero Position
Rotation Direction
Change
A
B
Index=0
1 LSB
Index
Step / Dir-Mode
Hyst=
2LSB
Index=1
3 LSB
LSB
Clockwise cw
Dir
CSn
Counterclockwise ccw
tDir valid
tIncremental outputs valid
7.2.2
LSB Output (Step/Direction Mode)
Output LSB reflects the LSB (least significant bit) of the programmed incremental resolution (OTP Register Bit Div0, Div1). Output Dir provides
information about the rotational direction of the magnet, which may be placed above or below the device (1=clockwise; 0=counter clockwise; top
view). Dir is updated with every LSB change. In both modes (quad A/B, step/direction), the resolution and the index output are user
programmable. The index pulse indicates the zero position and is by default one angular step (1LSB) wide. However, it can be set to three LSBs
by programming the Index-bit of the OTP register accordingly (see Table 20).
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Data Sheet - D e t a i l e d D e s c r i p t i o n
Incremental Power-up Lock Option. After power-up, the incremental outputs can optionally be locked or unlocked, depending on the
status of the CSn pin:
CSn = low at power-up: CSn has an internal pull-up resistor and must be externally pulled low ( R ext ≤ 5kΩ ). If Csn is low at power-up,
the incremental outputs (A, B, Index) will be high until the internal offset compensation is finished. This unique state (A=B=Index = high)
may 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 AS5140H 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.
7.2.3
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 2 LSB. Regardless of the programmed incremental resolution, the hysteresis of 2 LSB always
corresponds to the highest resolution of 10 bit. In absolute terms, the hysteresis is set to 0.704 degrees for all resolutions. For constant rotational
directions, every magnet position change is indicated at the incremental outputs (see Figure 9). 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 2 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 9. Hysteresis Window for Incremental Outputs
Incremental
Output
Indication
Hysteresis:
0.7º
X+4
X+3
X+2
X+1
X
X
X+1
X+2
X+3
X+4
X+5
Magnet Position
Clockwise Direction
Counterclockwise Direction
7.3 Pulse Width Modulation (PWM) Output
The AS5140H provides a pulse width modulated output (PWM), whose duty cycle is proportional to the measured angle:
t on ⋅ 1025
Position = ------------------------- – 1
( t on + t off )
(EQ 2)
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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AS5140H
Data Sheet - D e t a i l e d D e s c r i p t i o n
Figure 10. PWM Output Signal
PWMIN
Angle
0 deg
(Pos 0)
1µs
1025µs
PWMAX
359.65 deg
(Pos 1023)
1024µs
1/fPWM
Table 18. PWM Signal Parameters
Symbol
Parameter
Typ
Unit
Note
fPWM
PWM frequency
0.9756
kHz
Signal period: 1025µs
PWMIN
MIN pulse width
1
µs
- Position 0d
- Angle 0 deg
PWMAX
MAX pulse width
1024
µs
- Position 1023d
- Angle 359.65 deg
7.4 Analog Output
An analog output may be generated by averaging the PWM signal, using an external active or passive lowpass filter. The analog output voltage
is proportional to the angle: 0º = 0V; 360º = VDD5V. Using this method, the AS5140H can be used as direct replacement of potentiometers.
nd
Figure 11. Simple Passive 2 Order Lowpass Filter
Pin12
R2
R1
analog out
PWM
VDD
C1
C2
0V
Pin7
0º
360º
VSS
R1,R2 ≥ 4k7
C1,C2 ≥ 1µF / 6V
(EQ 3)
R1 should be ≥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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Data Sheet - D e t a i l e d D e s c r i p t i o n
7.5 Brushless DC Motor Commutation Mode
Brushless DC motors require angular information for stator commutation. The AS5140H provides U-V-W commutation signals for one and two
pole pair motors. In addition to the three-phase output signals, the step (LSB) output at pin 12 allows high accuracy speed measurement. Two
resolutions (9 or 10 bit) can be selected by programming Div0 according to Table 20.
Mode 3.0 (3.1) is used for brush-less DC motors with one-pole pair rotors. The three phases (U, V, W) are 120 degrees apart, each phase is 180
degrees on and 180 degrees off.
Mode 3.2 (3.3) is used for motors with two pole pairs requiring a higher pulse count to ensure a proper current commutation. In this case the
pulse width is 256 positions, equal to 90 degrees. The precise physical angle at which the U, V and W signals change state (“Angle” in Figure 12
and Figure 13) is calculated by multiplying each transition position by the angular value of 1 count:
Angle [deg] = Position x (360 degree / 1024)
(EQ 4)
Figure 12. U, V and V-Signals for BLDC Motor Commutation (Div1=0, Div0=0)
(One-pole-pair)
Commutation - Mode 3.0
Width : 512 Steps
Width : 512 Steps
U
V
W
CW Direction
Position:
0
171
341
512
683
853
0
Angle:
0.0
60.12
119.88
180.0
240.12
299.88
360.0
Figure 13. U, V and W-Signals for 2Pole BLDC Motor Commutation (Div1=1, Div0=0)
(Two-pole-pairs)
Commutation - Mode 3.2
Width : 256 Steps
Width : 256 Steps
U
V
W
CW Direction
Position:
Angle:
0
85
171
256
341
427
512
597
683
768
853
939
0
0.0
29.88
60.12
90.0
119.88
150.12
180.0
209.88
240.12
270.00
299.88
330.12
360.0
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7.6 Programming the AS5140H
Note: A detailed description of the austriamicrosystems low voltage polyfuse OTP programming method is given in Application Note AN514X10, which can be downloaded from the austriamicrosystems website. The OTP programming description in this datasheet is for general
information only.
After power-on, programming the AS5140H is enabled with the rising edge of CSn with Prog = high and CLK = low. The AS5140H programming
is a one-time-programming (OTP) method, based on polysilicon fuses. The advantage of this method is that a programming voltage of only 3.3V
is required for programming. 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.
The OTP memory can be accessed in several ways:
Load Operation: The Load operation reads the OTP fuses and loads the contents into the OTP register. Note that the 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.
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.
7.6.1
OTP Memory Assignment
Table 19. OTP Bit Assignment
Symbol
Function
mbit1
Factory Bit
51
Md0
50
Md1
49
Div0
48
Div1
47
Index
46
Z0
:
:
37
Z9
36
CCW
35
RA0
:
:
31
RA4
30
FS 0
Factory Bit
:
FS 1
Factory Bit
18
FS 12
Factory Bit
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10 bit Zero Position
Customer Section
Incremental Output Mode Selection
Direction
Redundancy Address
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Bit
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AS5140H
Data Sheet - D e t a i l e d D e s c r i p t i o n
Table 19. OTP Bit Assignment
Symbol
17
ChipID0
16
ChipID1
:
:
0
ChipID17
Function
18 bit Chip ID
mbit0
7.6.2
ID Section
Bit
Factory Bit
User Selectable Settings
The AS5140H allows programming of the following user selectable options:
-
Md1, Md0: Incremental Output Mode Selection.
Div1, Div0: Divider Setting of Incremental Output.
Index: Index Pulse Width Selection – 1LSB / 3LSB.
Z [9:0]: 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.
7.6.3
OTP Default Setting
The AS5140H can also be operated without programming. The default, un-programmed setting is as listed below.
-
7.6.4
Md0, MD1:00 = Incremental mode = quadrature.
Div0, Div1:00 = Incremental resolution = 10bit.
Index:0 = Index bit width = 1LSB.
Z9 to Z0:00 = No programmed zero position.
CCW:0 = Clockwise operation.
RA4 to RA0:0 = No OTP bit is selected.
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 RA5...0 in the OTP
user settings.
Example: Setting RA5…0 to “00001” will select bit 51 = MD0, “00010” selects bit 50 = MD1, “10000” selects bit 36 = CCW, etc.
7.6.5
OTP Register Entry and 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, PROG and CLK signals as shown in Figure 14.
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Data Sheet - D e t a i l e d D e s c r i p t i o n
Figure 14. OTP Access Timing Diagram
OTP Access
Setup Condition
CSn
PROG
CLK
Exit Condition
Operation Mode Selection
7.6.6
Incremental Mode Programming
The following three different incremental output modes are available:
Mode: Md1=0 / Md0=1 sets the AS5140H in quadrature mode.
Mode: Md1=1 / Md0=0 sets the AS5140H in step / direction mode (see Table 2).
In both modes listed above, the incremental resolution may be reduced from 10 bit down to 9, 8 or 7 bit using the divider OTP bits Div1 and Div0
(see Table 20 below).
Mode: Md1=1 / Md0=1 sets the AS5140H in brushless DC motor commutation mode with an additional LSB incremental signal at pin 12
(PWM_LSB).
To allow programming of all bits, the default factory setting is all bits = 0. This mode is equal to mode 1:0 (quadrature A/B, 1LSB index width,
256ppr). The absolute angular output value, by default, increases with clockwise rotation of the magnet (top view). Setting the CCW-bit (see
Table 19) allows for reversing the indicated direction, e.g. when the magnet is placed underneath the IC:
- CCW = 0 – angular value increases clockwise;
- CCW = 1 – angular value increases counterclockwise.
By default, the zero / index position pulse is one LSB wide. It can be increased to a three LSB wide pulse by setting the Index-bit of the OTP
register. Further programming options (commutation modes) are available for brushless DC motor-control.
Md1 = Md0 = 1 changes the incremental output pins 3, 4 and 6 to a 3-phase commutation signal. Div1 defines the number of pulses per
revolution for either a two-pole (Div1=0) or four-pole (Div1=1) rotor.
In addition, the LSB is available at pin 12 (the LSB signal replaces the PWM-signal), which allows for high rotational speed measurement of up to
10.000 rpm.
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Data Sheet - D e t a i l e d D e s c r i p t i o n
Table 20. One Time Programmable (OTP) Register Options
OTP-Mode-Register-Bit
Mode
Md1
Md0
0
0
0
0
0
1LSB
quadAB-Mode1.0
0
1
0
0
0
1LSB
quadAB-Mode1.1
0
1
0
0
1
3LSBs
quadAB-Mode1.2
0
1
0
1
0
Default (Mode0.0)
1
Div1 Div0
Pin#
Index
3
4
6
1LSB
A
B
quadAB-Mode1.3
0
1
0
1
1
quadAB-Mode1.4
0
1
1
0
0
1LSB
quadAB-Mode1.5
0
1
1
0
1
3LSBs
quadAB-Mode1.6
0
1
1
1
0
1LSB
quadAB-Mode1.7
0
1
1
1
1
3LSBs
Step/Dir-Mode2.0
1
0
0
0
0
1LSB
Step/Dir-Mode2.1
1
0
0
0
1
3LSBs
Step/Dir -Mode2.2
1
0
0
1
0
1LSB
Step/Dir -Mode2.3
1
0
0
1
1
3LSBs
Step/Dir -Mode2.4
1
0
1
0
0
Step/Dir -Mode2.5
1
0
1
0
1
3LSBs
Step/Dir -Mode2.6
1
0
1
1
0
1LSB
Step/Dir -Mode2.7
1
0
1
1
1
3LSBs
Commutation-Mode3.0
1
1
0
0
0
Commutation-Mode3.1
1
1
0
1
0
Commutation-Mode3.2
1
1
1
0
0
Commutation-Mode3.3
1
1
1
1
0
LSB
U(0º)
Dir
V(120º)
3LSBs
1LSB
W(240º)
U’
V’
W’
(0º,18 (60º,240º (120º,300º)
0º)
)
12
PWM
10 bit
Pulses per
Revolution
Incremental
Resolution
ppr
bit
2 x 256
10
2 x 128
9
2 x 64
8
2 x 32
7
512
10
256
9
128
8
64
7
PWM
10 bit
LSB
3x1
LSB
2x3
10
9
10
9
1. Div1, Div0 and Index cannot be programmed in Mode 0:0
7.6.7
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/index 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.
7.7 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 Prog = logic high (see Figure 16). The Data bits D9-D0 of the SSI change to a 10-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 Prog = low.
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Figure 15. Enabling the Alignment Mode
Prog
CSn
2µs
min.
AlignMode enable
Read-out
via SSI
exit AlignMode
Read-out
via SSI
2µs
min.
Figure 16. Exiting Alignment Mode
Prog
CSn
7.8 3.3V / 5V Operation
The AS5140H operates either at 3.3V ±10% or at 5V ±10%. This is made possible by an internal 3.3V Low-Dropout (LDO) voltage regulator. The
internal supply voltage is always taken from the output of the LDO, meaning that the internal blocks are always operating at 3.3V. For 3.3V
operation, the LDO must be bypassed by connecting VDD3V3 with VDD5V (see Figure 17).
For 5V operation, the 5V supply is connected to pin VDD5V, while VDD3V3 (LDO output) must be buffered by a 2.2...10µF capacitor, which is
supposed to be placed close to the supply pin (see Figure 17). 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 (see Figure
17). A buffer capacitor of 100nF is recommended in both cases close to pin VDD5V.
Note that pin VDD3V3 must always be buffered by a capacitor. It must not be left floating, as this may cause an instable internal 3.3V supply
voltage, which may lead to larger than normal jitter of the measured angle.
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AS5140H
Data Sheet - D e t a i l e d D e s c r i p t i o n
Figure 17. Connections for 5V / 3.3V Supply Voltages
5V Operation
3.3V Operation
2,2... 10µF
VDD3V3
VDD3V3
100n
VDD5V
100n
LDO
Internal
VDD
VDD5V
LDO
Internal
VDD
DO
DO
4.5 - 5.5V
I
N
T
E
R
F
A
C
E
VSS
PWM_LSB
-
-
+
+
CLK
3.0 - 3.6V
CSn
A_LSB_U
B_Dir_V
Index_W
Prog
VSS
I
N
T
E
R
F
A
C
E
PWM_LSB
CLK
CSn
A_LSB_U
B_Dir_V
Index_W
Prog
7.9 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 magnet’s field strength perpendicular to the die surface should be verified using a gaussmeter. The magnetic field Bv at a
given distance, along a concentric circle with a radius of 1.1mm (R1), should be in the range of ±45mT…±75mT. (see Figure 18).
7.9.1
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 IC package as shown in Figure 19.
Magnet Placement. The magnet’s center axis should be aligned within a displacement radius Rd of 0.25mm from the defined center of the IC
with reference to the edge of pin #1 (see Figure 19). This radius includes the placement tolerance of the chip within the SSOP-16 package (+/0.235mm). The displacement radius Rd is 0.485mm with reference to the center of the chip (see Alignment Mode on page 22).
The vertical distance should be chosen such that the magnetic field on the die surface is within the specified limits (see Figure 18). The typical
distance “z” between the magnet and the package surface is 0.5mm to 1.8mm with the recommended magnet (6mm x 2.5mm). Larger gaps are
possible, as long as the required magnetic field strength stays within the defined limits. A magnetic field outside the specified range may still
produce usable results, but the out-of-range condition will be indicated by MagINCn (pin 1) and MagDECn (pin 2), (see Table 16).
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AS5140H
Data Sheet - D e t a i l e d D e s c r i p t i o n
Figure 18. Typical Magnet and Magnetic Field Distribution
typ. 6mm diameter
N
S
Magnet axis
Magnet
axis
R1
Vertical field
component
N S
R1 concentric circle;
radius 1.1mm
Vertical field
component
Bv
(45…75mT)
0
360
360
Figure 19. Defined IC Center and Magnet Displacement Radius
3.9mm
3.9mm
2.433mm
1
Defined
center
2.433mm
Rd
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Area of recommended maximum magnet misalignment
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Data Sheet - D e t a i l e d D e s c r i p t i o n
Figure 20. Vertical Placement of the Magnet
N
S
N
Package surface
Die surface
Z
0.576mm ± 0.1mm
1.282mm ± 0.15mm
7.10 Simulation Modeling
With reference to Figure 21, a diametrically magnetized permanent magnet is placed above or below the surface of the AS5140H. The chip uses
an array of Hall sensors to sample the vertical vector of a magnetic field distributed across the device package surface. The area of magnetic
sensitivity is a circular locus of 1.1mm radius with respect to the center of the die. The Hall sensors in the area of magnetic sensitivity are
grouped and configured such that orthogonally related components of the magnetic fields are sampled differentially. The differential signal Y1-Y2
will give a sine vector of the magnetic field. The differential signal X1-X2 will give an orthogonally related cosine vector of the magnetic field.
Figure 21. Arrangement of Hall Sensor Array on Chip (principle)
3.9mm±0.235mm
1
2.433mm
Y1
±0.235mm
X1
X2
Y2
Center of die
AS5140H die
Radius of circular Hall sensor
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Data Sheet - D e t a i l e d D e s c r i p t i o n
The angular displacement (Θ) of the magnetic source with reference to the Hall sensor array may then be modelled by:
( Y1 – Y2 )
Θ = arctan ------------------------ ± 0.5º
( X1 – X2 )
(EQ 5)
The ±0.5º angular error assumes a magnet optimally aligned over the center of the die and is a result of gain mismatch errors of the AS5140H.
Placement tolerances of the die within the package are ±0.235mm in X and Y direction, using a reference point of the edge of pin #1 (Figure 21).
In order to neglect the influence of external disturbing magnetic fields, a robust differential sampling and ratiometric calculation algorithm has
been implemented. The differential sampling of the sine and cosine vectors removes any common mode error due to DC components introduced
by the magnetic source itself or external disturbing magnetic fields. A ratiometric division of the sine and cosine vectors removes the need for an
accurate absolute magnitude of the magnetic field and thus accurate Z-axis alignment of the magnetic source.
The recommended differential input range of the magnetic field strength (B(X1-X2),B(Y1-Y2)) is ±75mT at the surface of the die. In addition to this
range, an additional offset of ±5mT, caused by unwanted external stray fields is allowed. The chip will continue to operate, but with degraded
output linearity, if the signal field strength is outside the recommended range. Too strong magnetic fields will introduce errors due to saturation
effects in the internal preamplifiers. Too weak magnetic fields will introduce errors due to noise becoming more dominant.
7.11 Failure Diagnostics
The AS5140H also offers several diagnostic and failure detection features, which are discussed in detail further in the document.
7.11.1 Magnetic Field Strength Diagnosis
By Software: The MagINCn and MagDECn 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 is low, the magnet is either moving towards the chip (MagINCn) or away from
the chip (MagDECn).
7.11.2 Power Supply Failure Detection
By Software: If the power supply to the AS5140H is interrupted, the digital data read by the SSI will be all “0”s. Data is only valid, when bit OCF
is high, hence a data stream with all “0”s is invalid. To ensure adequate low levels in the failure case, a pull-down resistor (~10kΩ) should be
added between pin DO 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 Table 16). In a failure case, either when the magnetic field is out of range or the power supply is
missing, these outputs will become low. To ensure adequate low levels in case of a broken power supply to the AS5140H, the pull-up resistors
(>10kΩ) from each pin must be connected to the positive supply at pin 16 (VDD5V).
By Hardware - PWM Output: The PWM output is a constant stream of pulses with 1kHz repetition frequency. In case of power loss, these
pulses are missing.
By Hardware - Incremental Outputs: In normal operation, pins A(#3), B(#4) and Index (#6) will never be high at the same time, as Index is only
high when A=B=low. However, after a power-on-reset, if VDD is powered up or restarts after a power supply interruption, all three outputs will
remain in high state until pin CSn is pulled low. If CSn is already tied to VSS during power-up, the incremental outputs will all be high until the
internal offset compensation is finished (within tPwrUp).
7.12 Angular Output Tolerances
7.12.1 Accuracy
Accuracy is defined as the error between the measured angle and the actual angle. It is influenced by several factors:
The non-linearity of the analog-digital converters
Internal gain and mismatch errors
Non-linearity due to misalignment of the magnet
As a sum of all these errors, the accuracy with centered magnet = (Errmax – Errmin)/2 is specified as better than ±0.5 degrees @ 25ºC (see
Figure 23). Misalignment of the magnet further reduces the accuracy. Figure 22 shows an example of a 3D-graph displaying non-linearity over
XY-misalignment. The center of the square XY-area corresponds to a centered magnet (see dot in the center of the graph). The X- and Y- axis
extends to a misalignment of ±1mm in both directions. The total misalignment area of the graph covers a square of 2x2 mm (79x79mil) with a
step size of 100µm. For each misalignment step, the measurement as shown in Figure 23 is repeated and the accuracy (Errmax – Errmin)/2 (e.g.
0.25º in Figure 23) is entered as the Z-axis in the 3D-graph.
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AS5140H
Data Sheet - D e t a i l e d D e s c r i p t i o n
Figure 22. Example of Linearity Error Over XY Misalignment
6
5
4
3
800
500
2
200
1
-100
x
-1000
-1000
-800
-600
-400
-200
y
-700
0
200
400
-400
600
800
1000
0
The maximum non-linearity error on this example is better than ±1 degree (inner circle) over a misalignment radius of ~0.7mm. For volume
production, the placement tolerance of the IC within the package (±0.235mm) must also be taken into account. The total nonlinearity error over
process tolerances, temperature and a misalignment circle radius of 0.25mm is specified better than ±1.4 degrees.
Note: The magnet used for this measurement was a cylindrical NdFeB (Bomatec® BMN-35H) magnet with 6mm diameter and 2.5mm in
height.
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AS5140H
Data Sheet - D e t a i l e d D e s c r i p t i o n
Figure 23. Example of Linearity Error Over 360º
0.5
0.4
0.3
0.2
transition noise
0.1
Err max
0
-0.1
1
55
109
163
217
271
325
379
433
487
541
595
649
703
757
811
865
919
973
Err min
-0.2
-0.3
-0.4
-0.5
7.12.2 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
1
outputs. It is specified as 0.06 degrees rms (1 sigma) . 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 applying an averaging of readings. An averaging of 4 readings will reduce the transition noise by 50% = 0.03º rms (1 sigma).
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 10.000 rpm and higher).
7.12.3 High Speed Operation
The AS5140H samples the angular value at a rate of 10.42k samples per second. Consequently, the incremental and the absolute outputs are
updated each by 96µs. At a stationary position of the magnet, this sampling rate creates no additional error.
Absolute Mode. With the given sampling rate of 10.4 kHz, the number of samples (n) per turn for a magnet rotating at high speed can be
calculated by:
60
n = --------------------------rpm ⋅ 96μs
(EQ 6)
In practice, there is no upper speed limit. The only restriction is that there will be fewer samples per revolution as the speed increases.
Regardless of the rotational speed, the absolute angular value is always sampled at the highest resolution of 10 bit. Likewise, for a given number
of samples per revolution (n), the maximum speed can be calculated by:
60
rpm = -------------------n ⋅ 96μs
(EQ 7)
1. Statistically, 1 sigma represents 68.27% of readings; 3 sigma represents 99.73% of readings.
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AS5140H
Data Sheet - D e t a i l e d D e s c r i p t i o n
In absolute mode (serial interface and PWM output), 610 rpm is the maximum speed, where 1024 readings per revolution can be obtained. In
incremental mode, the maximum error caused by the sampling rate of the ADCs is 0/+96µs. It has a peak of 1LSB = 0.35º at 610 rpm. At higher
speeds, this error is reduced again due to interpolation and the output delay remains at 192µs as the DSP requires two sampling periods
(2x96µs) to synthesize and redistribute any missing pulses.
Incremental Mode. Incremental encoders are usually required to produce no missing pulses up to several thousand rpm. Therefore, the
AS5140H has a built-in interpolator, which ensures that there are no missing pulses at the incremental outputs for rotational speeds of up to
10.000 rpm, even at the highest resolution of 10 bits (512 pulses per revolution).
Table 21. Speed Performance
Absolute Output Mode
Incremental Output Mode
610rpm = 1024 samples / turn
No missing pulses
@ 10 bit resolution (512ppr):
122rpm = 512 samples / turn
2441rpm = 256 samples / turn
max. speed = 10.000 rpm
etc.
7.12.4 Propagation Delays
The propagation delay is the delay between the time that a sample is taken until it is converted and available as angular data. This delay is 48µs
for the absolute interface and 192µs for the incremental interface. Using the SSI interface for absolute data transmission, an additional delay
must be considered, caused by the asynchronous sampling (t=0…1/fs) and the time it takes the external control unit to read and process the
data.
Angular Error Caused by Propagation Delay. A rotating magnet will therefore cause an angular error caused by the output delay. This
error increases linearly with speed:
esampling = rpm * 6 * prop.delay
(EQ 8)
Where:
esampling = angular error [º]
rpm = rotating speed [rpm]
prop.delay = propagation delay [seconds]
Note: Since the propagation delay is known, it can be automatically compensated by the control unit that is processing the data from the
AS5140H, thus reducing the angular error caused by speed.
7.12.5 Internal Timing Tolerance
The AS5140H does not require an external ceramic resonator or quartz. All internal clock timings for the AS5140H 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 100µs (typ.)
Incremental outputs: The incremental outputs are updated every 100µs (typ.)
PWM output: A new angular value is updated every 100µs (typ.). The PWM pulse timings Ton and Toff also have the same tolerance as the
internal oscillator. If only the PWM pulse width Ton is used to measure the angle, the resulting value also has this timing tolerance. However,
this tolerance can be cancelled by measuring both Ton and Toff and calculating the angle from the duty cycle (see Pulse Width Modulation
(PWM) Output on page 16):
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t on ⋅ 1025
Position = ------------------------- – 1
( t on + t off )
(EQ 9)
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Data Sheet - D e t a i l e d D e s c r i p t i o n
7.12.6 Temperature
Magnetic Temperature Coefficient. One of the major benefits of the AS5140H, in comparison 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 coefficient, the AS5140H automatically
compensates for the varying magnetic field strength over temperature. The magnet’s temperature drift does not need to be considered, as the
AS5140H 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 +150º = 190K. The magnetic field change is: 190 x -0.12% = -22.8%, which corresponds to 75mT at -40ºC and 57.9mT at 150ºC.
In the above described scenario, the AS5140H can automatically compensate for the change in temperature related field strength. No user
adjustment is required.
Accuracy Over Temperature. The influence of temperature in the absolute accuracy is very low. While the accuracy is ≤ ±0.5º at room
temperature, it may increase 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 (see Internal Timing Tolerance on page 30).
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Data Sheet - A p p l i c a t i o n I n f o r m a t i o n
8 Application Information
The benefits of AS5140H are as follows:
Complete system-on-chip
Flexible system solution provides absolute, PWM and incremental outputs simultaneously
Ideal for applications in harsh environments due to contactless position sensing
Tolerant to magnet misalignment and airgap variations
Tolerant to external magnetic fields
Operates up to +150ºC ambient temperature
No temperature compensation necessary
No calibration required
10, 9, 8 or 7-bit user programmable resolution
Small Pb-free package: SSOP 16 (5.3mm x 6.2mm)
8.1 AS5140H Differences to AS5040
The AS5140H and AS5040 differ in the following features:
Table 22. Differences Between AS5140H and AS5040
Parameter
AS5140H
AS5040
Pin - assignment
Pin - compatible
Ambient temperature
range
-40ºC …+150ºC
Alignment mode
Exit alignment mode by power-on-reset,
Exit alignment mode by POR or with PROG=low @ falling Exit alignment mode by power-on-reset only.
edge of CSn.
OTP programming
voltage
3.0 to 3.6V
7.3 to 7.5V
OTP programming
options
Incremental modes (quad AB, step/dir, BLDC)
Incremental resolution
Incremental Index bit width
10-bit Zero position
Direction bit (cw/ccw)
Redundancy address (1 of 16)
18-bit Chip-Identifier
Incremental modes (quad AB, step/dir, BLDC)
Incremental resolution
Incremental Index bit width
10-bit Zero position
Direction bit (cw/ccw)
OTP Programming
protocol
CSn, Prog and CLK;
52-bit serial data protocol
CSn, Prog and CLK;
16-bit (32-bit) serial data protocol
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-40ºC…+125ºC
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Data Sheet - P a c k a g e D r a w i n g s a n d M a r k i n g s
9 Package Drawings and Markings
The device is available in a 16-Lead Shrink Small Outline Package.
Figure 24. SSOP-16 Package Drawings
AYWWIZZ
AS5140H
Table 23. SSOP-16 Package Dimensions
Symbol
mm
inch
Min
Typ
Max
Min
Typ
Max
A
1.73
1.86
1.99
0.068
0.073
0.078
A1
0.05
0.13
0.21
0.002
0.005
0.008
A2
1.68
1.73
1.78
0.066
0.068
0.070
b
0.25
0.315
0.38
0.010
0.012
0.015
c
0.09
-
0.20
0.004
-
0.008
D
6.07
6.20
6.33
0.239
0.244
0.249
E
7.65
7.8
7.9
0.301
0.307
0.311
E1
5.2
5.3
5.38
0.205
0.209
0.212
e
0.65
0.0256
K
0º
-
8º
0º
-
8º
L
0.63
0.75
0.95
0.025
0.030
0.037
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AS5140H
Data Sheet - P a c k a g e D r a w i n g s a n d M a r k i n g s
9.1 Recommended PCB Footprint
Figure 25. PCB Footprint
Table 24. Recommended Footprint Data
Symbol
mm
inch
A
9.02
0.355
B
6.16
0.242
C
0.46
0.018
D
0.65
0.025
E
5.01
0.197
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AS5140H
Data Sheet - R e v i s i o n H i s t o r y
Revision History
Revision
Date
1.0
Oct 03, 2006
1.2
Mar 05, 2009
1.3
Mar 30, 2009
1.4
Sep 23, 2009
Owner
Description
Initial revision
apg
Updated parameter values for tDO valid (see Table 13)
Application Note AN5000-30 changed to AN514X-10 (see Programming the
AS5140H on page 19)
Updated parameter values for PWMIN and PWMAX (see Table 14)
rfu
Updated Figure 14
Note: Typos may not be explicitly mentioned under revision history.
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AS5140H
Data Sheet - O r d e r i n g I n f o r m a t i o n
10 Ordering Information
The devices are available as the standard products shown in Table 25.
Table 25. Ordering Information
Ordering Code
Description
Delivery Form
Package
AS5140HASSU
Tubes
SSOP-16
AS5140HASST
Tape & Reel
SSOP-16
Note: All products are RoHS compliant and Pb-free.
Buy our products or get free samples online at ICdirect: http://www.austriamicrosystems.com/ICdirect
For further information and requests, please contact us mailto:[email protected]
or find your local distributor at http://www.austriamicrosystems.com/distributor
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AS5140H
Data Sheet - C o p y r i g h t s
Copyrights
Copyright © 1997-2009, austriamicrosystems AG, Tobelbaderstrasse 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.
All products and companies mentioned are trademarks or registered trademarks of their respective companies.
Disclaimer
Devices sold by austriamicrosystems AG are covered by the warranty and patent indemnification provisions appearing in its Term of Sale.
austriamicrosystems AG makes no warranty, express, statutory, implied, or by description regarding the information set forth herein or regarding
the freedom of the described devices from patent infringement. austriamicrosystems 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 austriamicrosystems AG for
current information. This product is intended for use in normal 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 austriamicrosystems AG for each application. For shipments of less than 100
parts the manufacturing flow might show deviations from the standard production flow, such as test flow or test location.
The information furnished here by austriamicrosystems AG is believed to be correct and accurate. However, austriamicrosystems 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
austriamicrosystems AG rendering of technical or other services.
Contact Information
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austriamicrosystems AG
Tobelbaderstrasse 30
A-8141 Unterpremstaetten, Austria
Tel: +43 (0) 3136 500 0
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For Sales Offices, Distributors and Representatives, please visit:
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