AMS AS5040 Position Sensor Datasheet
Below you will find brief information for AS5040. This 10-bit programmable magnetic rotary encoder offers contactless, high-resolution rotational position encoding over 360 degrees. It features user-programmable resolution, pole pairs, and zero position. It includes various interfaces (SSI, PWM, quadrature A/B, Step/Direction, 3-Phase commutation) and is ideal for motor applications, with speeds up to 30000 rpm and failure detection mode.
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General Description
AS5040
10-Bit 360º Programmable Magnetic
Rotary Encoder
The AS5040 is a contactless magnetic rotary encoder for accurate angular measurement over a full turn of 360°. 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 0.35° = 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, making the chip suitable for replacement of various optical encoders.
An internal voltage regulator allows the AS5040 to operate at either 3.3 V or 5 V supplies.
and
datasheet.
Figure 1:
Typical Arrangement of AS5040 and Magnet ams Datasheet
[v2-12] 2017-Jun-20
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AS5040 −
General Description
Key Benefits & Features
The benefits and features of AS5040, 10-Bit 360º Programmable
Magnetic Rotary Encoder are listed below:
Figure 2:
Added Value of Using AS5040
Benefits
•
Highest reliability and durability
•
Simple programming
•
Multiple interfaces
•
Ideal for motor applications
•
Failure diagnostics
•
Easy setup
•
Great flexibility at a huge application area
•
Fully automotive qualified
•
Small form factor
•
Robust environmental tolerance
Features
•
Contactless high resolution rotational position encoding over a full turn of 360 degrees
•
Simple user-programmable resolution, pole pairs and zero position
•
Serial communication interface (SSI)
•
10-bit pulse width modulated (PWM) output
•
Quadrature A/B and Index output signal
•
Step/Direction and Index output signal
•
3-Phase commutation for brushless DC motors
•
Rational speeds up to 30000 rpm
•
Failure detection mode for magnet placement monitoring and loss of power supply
•
Serial read-out of multiple interconnected devices using daisy chain mode
•
Push button functionality detects movement of magnet in
Z-axis
•
AEC-Q100, grade 1
•
SSOP 16 (5.3mm x 6.2mm)
•
Wide temperature range: -40°C to 125°C
Applications
AS5040 is ideal for:
•
Industrial applications:
• Contactless rotary position sensing
• Robotics
• Brushless DC motor commutation
• Power tools
•
Automotive applications:
• Steering wheel position sensing
• Gas pedal position sensing
• Transmission gearbox encoder
• Headlight position control
• Power seat position indicator
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AS5040 −
General Description
•
Office equipment: printers, scanners, copiers
•
Replacement of optical encoders
•
Front panel rotary switches
•
Replacement of potentiometers
Block Diagram
The functional blocks of this device are shown below:
Figure 3:
AS5040 Block Diagram
VDD5V
VDDV3V
LDO 3.3V
DSP
Hall Array
&
Frontend
Amplifier
Cos
OTP
Register
Programming
Parameters
PWM
Interface
Ang
Mag
Absolute
Interface
(SSI)
Incremental
Interface
MagINCn
MagDECn
PWM_LSB
DO
CSn
CLK
A_LSB_U
B_Dir_V
Index_W
Prog
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AS5040 −
Pin Assignment
Pin Assignment
Figure 4:
Pin Configuration SSOP16
MagINCn
MagDECn
A_LSB_U
B_Dir_V
NC
Index_W
VSS
Prog
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
VDD5V
VDD3V3
NC
NC
PWM_LSB
CSn
CLK
DO
Pin Description
Figure 6 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
).
Pins 7, 15 and 16 are supply pins, pins 5, 13 and 14 are for internal use and must not be connected.
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.
Figure 5:
Pin Assignment for the Different Incremental Output Modes
Output Mode Pin 3 Pin 4
1.x: quadrature A B
2.x:step/direction LSB Direction
3.x: commutation U V
Pin 6
Index
Index
W
Pin 12
PWM
PWM
LSB
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AS5040 −
Pin Assignment
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.
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
AS5040 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
This pin is also used as digital input to shift serial data through the device in
.
Pin 11 Chip Select (CSn; active low) selects a device within a network of AS5040 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
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 1
μ s pulse width per step (1
μ s to 1024
μ s 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.
Figure 6:
Pin Description SSOP16
Pin Symbol Type Description
Mag
nitude
INC
rease; active low, indicates a distance reduction between the magnet and the device surface.
Mag
nitude
DEC
rease; active low, indicates a distance increase between the device and the magnet.
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AS5040 −
Pin Assignment
Pin Symbol Type Description
Mode1.x:
Quadrature
A
channel
3 A_LSB_U DO
L
east
S
ignificant
B
it
Mode3.x:
U
signal (phase1)
Mode1.x
: Quadrature
B
channel quarter period shift to channel A.
4 B_Dir_V DO
Dir
ection of Rotation
Mode3.x:
V
signal (phase2)
5 NC Must be left unconnected
Mode1.x and Mode2.x
:
Index
signal indicates the absolute zero
6 Index_W
7 VSS S
Mode3.x
:
W
signal (phase3)
Negative Supply Voltage (GND)
OTP
Prog
ramming Input and Data Input for Daisy Chain mode.
May be connected to VSS if programming is not used
D
ata
O
utput of Synchronous Serial Interface 9 DO DO_T
10 CLK DI, oc
k
Input of Synchronous Serial Interface; Schmitt-Trigger input
12
13
PWM_LSB
NC
DO
-
S
elect, active low; Schmitt-Trigger input, internal pull-up resistor (~50kΩ) connect to VSS in incremental mode (see 0)
P
ulse
W
idth
M
odulation of approx. 1kHz;
Must be left unconnected
14 NC Must be left unconnected
15 VDD3V3 S 3V-Regulator
16 VDD5V S Positive Supply Voltage 5 V
LSB
in
Mode3.x
Abbreviations for Pin Types in
:
DO_OD : Digital output open drain
DO : Digital output
DI_PD
DI_PU
: Digital input pull-down
: Digital input pull-up
S
DI
DO_T
ST
: Supply pin
: Digital input
: Digital output /tri-state
: Schmitt-Trigger input
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AS5040 −
Absolute Maximum Ratings
Absolute Maximum Ratings
Stresses beyond those listed in
may cause permanent damage to the device. These are stress ratings only. Functional operation of the device at these or any other conditions beyond those indicated in
is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
Figure 7:
Absolute Maximum Ratings
Symbol
VDD5V
VDD3V3
Parameter
DC supply voltage at pin
VDD5V
DC supply voltage at pin
VDD3V3
Vin Input pin voltage
Min Max Units
-0.3 7 V
Note
-0.3 5 V
-0.3
7.5
V
Pins MagINCn, MagDECn, CLK,
CSn
Pin Prog
I scr
ESD
T strg
T
Body
RH
NC
MSL
Input current
(latchup immunity)
Electrostatic discharge
Storage temperature
Body temperature
(Lead free package)
Relative humidity (non condensing)
Moisture sensitivity level
-55
±2
125 kV
ºC
MIL 883 E method 3015
Min – 67°F, Max 257°F t=20s to 40s,
Lead finish 100% Sn “matte tin”
5 85 %
3 Maximum floor life time of 168h
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AS5040 −
Electrical Characteristics
Electrical Characteristics
Operating Conditions
Figure 8:
Operating Conditions
Symbol
T amb
I supp
VDD5V
VDD3V3
VDD5V
VDD3V3
Parameter
Ambient temperature
Supply current
External supply voltage at pin
VDD5V
Internal regulator output voltage at pin VDD3V3
External supply voltage at pin
VDD5V, VDD3V3
Min Typ Max Unit
-40
16
125
21
°C mA
Note
-40°F to 257°F
4.5
3.0
3.0
3.0
5.0
3.3
3.3
3.3
5.5
3.6
3.6
3.6
V
V
V
V
5V operation
3.3V operation (pins VDD5V and VDD3V3 connected)
DC Characteristics for Digital Inputs and
Outputs
CMOS Schmitt-Trigger Inputs: CLK, CSn
(CSn = Internal Pull-Up)
Operating conditions: T amb
= -40°C to 125°C,
VDD5V = 3.0V to 3.6V (3V operation) VDD5V = 4.5V to 5.5V (5V operation) unless otherwise noted.
Figure 9:
CMOS Schmitt-Trigger Inputs: CLK, CSn (CSn = Internal Pull-Up)
Symbol
V
IH
V
IL
V
Ion
-V
Ioff
I
LEAK
I iL
Parameter
High level input voltage
Low level input voltage
Schmitt trigger hysteresis
Input leakage current
Pull-up low level input current
Min Max Unit
0.7 * VDD5V
0.3 * VDD5V
1 V
-1 1
μA
-30 -100
V
V
Note
Normal operation
CLK only
CSn only, VDD5V: 5.0V
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AS5040 −
Electrical Characteristics
CMOS / Program Input: Prog
Operating conditions: T amb
= -40°C to 125°C, VDD5V = 3.0V to
3.6V (3V operation) VDD5V = 4.5V to 5.5V (5V operation) unless otherwise noted.
Figure 10:
CMOS / Program Input: Prog
Symbol
V
IH
Parameter
High level input voltage
V
PROG
High level input voltage
V
IL
I iL
Low level input voltage
Pull-down high level input current
Min Max
0.7 * VDD5V 5
See
0.3 * VDD5V
100
Unit
V
V
V
Note
During programming
μ
A VDD5V:
CMOS Output Open Drain: MagINCn, MagDECn
Operating conditions: T amb
= -40°C to 125°C, VDD5V = 3.0V to
3.6V (3V operation) VDD5V = 4.5V to 5.5V (5V operation) unless otherwise noted.
Figure 11:
CMOS Output Open Drain: MagINCn, MagDECn
Note Symbol
V
OL
Parameter
Low level output voltage
I
O
I
OZ
Output current
Open drain leakage current
Min Max
VSS+0.4
4
2
1
Unit
V mA
μ
A
VDD5V: 4.5V
VDD5V: 3V
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Electrical Characteristics
CMOS Output: A, B, Index, PWM
Operating conditions: T amb
= -40°C to 125°C, VDD5V = 3.0V to
3.6V (3V operation) VDD5V = 4.5V to 5.5V (5V operation) unless otherwise noted.
Figure 12:
CMOS Output: A, B, Index, PWM
Symbol
V
OH
V
OL
Parameter
High level output voltage
Low level output voltage
I
O
Output current
Min
VDD5V-0.5
Max
VSS+0.4
4
2
Unit
V
V mA
Note
VDD5V: 4.5V
VDD5V: 3V
Tristate CMOS Output: DO
Operating conditions: T amb
= -40°C to 125°C, VDD5V = 3.0V to
3.6V (3V operation) VDD5V = 4.5V to 5.5V (5V operation) unless otherwise noted.
Figure 13:
Tristate CMOS Output: DO
Symbol
V
OH
V
OL
Parameter
High level output voltage
Low level output voltage
I
O
Output current
I
OZ
Tri-state leakage current
Min
VDD5V-0.5
Max
VSS+0.4
4
2
1
Unit
V
V mA
μ
A
Note
VDD5V: 4.5V
VDD5V: 3V
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AS5040 −
Electrical Characteristics
Magnetic Input Specification
Operating conditions: T amb
= -40°C to 125°C, VDD5V = 3.0V to
3.6V (3V operation) VDD5V = 4.5V to 5.5V (5V operation) unless otherwise noted.
Two-pole cylindrical diametrically magnetized source:
Figure 14:
Magnetic Input Specification
Symbol
d mag t mag
Parameter Min Typ Max Unit Note
Diameter
Recommended magnet: Ø 6mm x
B pk
B off
Magnetic input field amplitude
Magnetic offset
Field non-linearity
45 75
± 10
5 mT
Required vertical component of the magnetic field strength on the die’s surface, measured along a concentric circle with a radius of 1.1mm mT Constant magnetic stray field
% Including offset gradient f mag_abs f mag_inc
Input frequency
(rotational speed of magnet)
Disp
Displacement radius
Chip placement tolerance
Recommended magnet material and temperature drift
10 Hz
Incremental mode: no missing pulses
-0.12
0.25
0.485
±0.23 5 mm mm
)
Max. X-Y offset between defined IC package center and magnet axis (see
Max. X-Y offset between chip center and magnet axis.
Placement tolerance of chip within IC
)
NdFeB (Neodymium Iron Boron)
%/K
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AS5040 −
Electrical Characteristics
Electrical System Specifications
Operating conditions: T amb
= -40°C to 125°C, VDD5V = 3.0V to
3.6V (3V operation) VDD5V = 4.5V to 5.5V (5V operation) unless otherwise noted.
Figure 15:
Electrical System Specifications
Symbol
RES
LSB
INL opt
Integral non-linearity
(optimum)
INL temp
Integral non-linearity
(optimum)
INL
Parameter
Resolution
7 bit
8 bit
9 bit
10 bit
Integral non-linearity
Min Typ Max Unit Note
2.813
1.406
0.703
0.352
10 bit 0.352 deg
deg
Adjustable resolution only available for incremental output modes;
Least significant bit, minimum step
± 0.5
± 0.9 deg deg
Maximum error with respect to the best line fit.
Verified at optimum magnet placement, T amb
=25 °C.
Maximum error with respect to the best line fit.
Verified at optimum magnet placement,
T amb
= -40°C to 125°C
± 1.4 deg
Best line fit = (Err max
– Err min
) / 2
Over displacement tolerance with 6mm diameter magnet,
T amb
= -40°C to 125°C
± 0.176 deg 10bit, no missing codes DNL Differential non-linearity
RMS equivalent to 1 sigma t
PwrUp t
Hyst
V
V on off delay
Hysteresis
Power-on-reset threshold
ON voltage; 300mV typ. hysteresis
Power-on-reset threshold
OFF voltage; 300mV typ. hysteresis
1.37
0.704
2.2
deg Incremental modes only
1.08 1.9 2.6 V
DC supply voltage 3.3V
(VDD3V3)
Power-up time 50 ms
Until offset compensation finished
System propagation delay absolute output
System propagation delay incremental output
48
192
μs
μs
Includes delay of ADC and DSP
Calculation over two samples
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AS5040 −
Electrical Characteristics
Symbol
f
S
Parameter Min Typ Max Unit Note
Sampling rate for absolute output
9.90 10.42 10.94
9.38 10.42 11.46 kHz
Internal sampling rate,
T amb
= 25°C
Internal sampling rate,
T amb
= -40°C to 125°C
Figure 16:
Integral and Differential Non-Linearity Example (Exaggerated Curve)
1023
D
10bit code
2
1
0
512
Actual curve
TN
0.35°
INL
DNL+1LSB
Ideal curve
512
1023
0
0 q q
360 q
D
[degrees]
Integral Non-Linearity (INL) is the maximum deviation between actual position and indicated position.
Differential Non-Linearity (DNL) is the maximum deviation of the step length from one position to the next.
Transition Noise (TN) is the repeatability of an indicated position.
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AS5040 −
Electrical Characteristics
Timing Characteristics
Synchronous Serial Interface (SSI)
Operating conditions: T amb
= -40°C to 125°C, VDD5V = 3.0V to
3.6V (3V operation) VDD5V = 4.5V to 5.5V (5V operation) unless otherwise noted.
Figure 17:
Synchronous Serial Interface (SSI)
Symbol Parameter
t
DO active t
CLK FE
Data output activated
(logic high)
First data shifted to output register
T
CLK / 2
Start of data output
Min Typ Max Unit
500 t
DO valid
Data output valid t
DO tristate
Data output tristate t
CSn f
CLK
Pulse width of CSn
Read-out frequency
357
500
>0
Note
413
100
1 ns ns ns ns
MHz
Rising edge of CLK shifts out one bit at a time
Time between rising edge of CLK and data output valid
After the last bit DO changes back to
“tristate”
CSn = high; To initiate read-out of next angular position
Clock frequency to read out serial data
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AS5040 −
Electrical Characteristics
Figure 18:
Pulse Width Modulation Output
Symbol
f
PWM
Parameter
PWM frequency
PW
MIN
Minimum pulse width
PW
MAX
Maximum pulse width
Min Typ Max Unit Note
0.927 0.976 1.024
0.878 0.976 1.074
0.90 1 1.10
Signal period = 1025
μ s ±5% at
T amb
= 25°C kHz
=1025μs ±10% at
T amb
= -40°C to 125°C
μ s Position 0d; angle 0 degree
922 1024 1126
μ s
Position 1023d; angle 359.65 degree
Incremental Outputs
Operating conditions: T amb
= -40°C to 125°C, VDD5V = 3.0V to
3.6V (3V operation) VDD5V = 4.5V to 5.5V (5V operation) unless otherwise noted.
Figure 19:
Incremental Outputs
Pulse Width Modulation Output
Operating conditions: T amb
= -40°C to 125°C, VDD5V = 3.0V to
3.6V (3V operation) VDD5V = 4.5V to 5.5V (5V operation) unless otherwise noted.
Symbol Parameter
t
Incremental outputs valid
Incremental outputs valid after power-up t
Dir valid
Directional indication valid
Min Typ Max Unit Note
Time between first falling edge of incremental outputs
Time between rising or falling edge indication
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AS5040 −
Electrical Characteristics
Programming Conditions
(operating conditions: T amb
= -40°C to 125°C, VDD5V = 3.0V to
3.6V (3V operation) VDD5V = 4.5V to 5.5V (5V operation) unless otherwise noted).
Figure 20:
Programming Conditions
Symbol
t
Prog enable t
Data in t
Load PROG t
PrgR t
PrgH
CLK
PROG
Parameter
Programming enable time
Write data start t
Data in valid
Write data valid
Load programming data
Rise time of V
PROG before CLK
PROG
Hold time of V
PROG after CLK
PROG
Write data – programming CLK
PROG
Min Typ Max Unit
2
μ s
Note
Time between rising edge at
Prog pin and rising edge of CSn
2
μ s
250 ns
Write data at the rising edge of
CLK
PROG
3
μ s
0
μ s
250 kHz t
PROG t
PROG finished
Hold time of Vprog after programming
V
PROG
CLK pulse width
Programming voltage
1.8
2
7.3
2
7.4
2.2
7.5
μ s
μ s
V
During programming; 16 clock cycles
Programmed data is available after next power-on
Must be switched OFF after zapping
V
ProgOff
Programming voltage
OFF level
I
PROG
CLK
Aread
Programming current
Analog read CLK
V programmed
Programmed zener voltage (log.1)
V unprogrammed
Unprogrammed zener voltage (log. 0)
1
130 mA During programming
100 kHz Analog readback mode
100 mV V
Ref
-V
PROG
during analog
V
)
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AS5040 −
Functional Description
Functional Description
The AS5040 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 AS5040 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 AS5040 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).
Besides the absolute angular position information the device simultaneously provides incremental output signals. The various incremental output modes can be selected by programming the OTP mode register bits (see
). 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 (see
Figure 34 ). 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 AS5040 is tolerant to magnet misalignment and magnetic stray fields due to differential measurement technique and Hall sensor conditioning circuitry.
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AS5040 −
10-Bit Absolute Angular Position Output
10-Bit Absolute Angular
Position Output
Synchronous Serial Interface (SSI)
Figure 21:
Synchronous Serial Interface with Absolute Angular Position Data
CSn t
CLK FE
T
CLK / 2
1
t
CSn
CLK
8 16
DO t
DO active
D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
OCF COF LIN
M a g
I N C
M a g
D E C
Even
PAR
t
DO valid
Angular Position Data
Status Bits t
DO Tristate t
CLK FE
1
D9
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 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 t
CSn
.
Data Content
D9:D0
absolute angular position data (MSB is clocked out first)
OCF
(
O
ffset
C
ompensation
F
inished), 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 AS5040 has completed the startup and the data is valid (see
COF
(
C
ORDIC
O
verflow), 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.
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Figure 22:
Magnetic Magnitude Variation Indicator
This alarm may be resolved by bringing the magnet within the X-Y-Z tolerance limits.
LIN
(
Lin
earity 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
, (
Mag
nitude
Inc
rease) becomes HIGH, when the magnet is pushed towards the IC, thus the magnetic field strength is increasing.
MagDECn
, (
Mag
nitude
Dec
rease) becomes HIGH, when the magnet is pulled away from the IC, thus the magnetic field strength is decreasing.
Both signals HIGH indicate a magnetic field that is out of the allowed range (see
Mag
INCn
0
0
1
1
Mag
DECn
0
1
0
1
Description
No distance change; Magnetic input field OK (in range, 45mT to 75mT)
Distance increase: Pull-function. This state is dynamic, it is only active while the magnet is moving away from the chip in Z-axis
Distance decrease: Push- function. This state is dynamic, it is only active while the magnet is moving towards the chip in Z.-axis.
Magnetic Input Field invalid – out of range: <45mT or >75mT (or missing magnet)
Note(s):
1. 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.
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AS5040 −
10-Bit Absolute Angular Position Output
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
Even Parity
bit for transmission error detection of bits 1 to 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:
Figure 23:
Status Bit Outputs
OCF COF LIN
1 0 0
Mag INCn
0
0
1
Mag DECn
0
1
0
Parity
Even checksum of bits 1:15
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 1200rpm.
Consequently, increasing the rotational speed reduces the number of absolute angular positions per revolution (see
Figure 46 ). 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 30000 rpm without missing pulses.
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AS5040 −
10-Bit Absolute Angular Position Output
Daisy Chain Mode
The Daisy Chain mode allows connection of several AS5040’s in series, while still keeping just one digital input for data transfer (see “Data IN” in
below). This mode is accomplished by connecting the data output (DO; pin 9) to the data input (Prog; pin 8) of the subsequent device. An RC filter must be implemented between each PROG pin of device n and
DO pin of device n+1, to prevent the encoders to enter the alignment mode, in case of ESD discharge, long cables, or not conform signal levels or shape. Using the values R=100R and
C=1nF allow a max. CLK frequency of 1MHz on the whole chain.
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: e.g. 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
).
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
During programming (see
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)
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Figure 24:
Daisy Chain Hardware Configuration
AS5040 −
10-Bit Absolute Angular Position Output
Due to the parallel connection of CLK and CSn, all connected devices may be programmed simultaneously.
MCU
CSn
CLK
DI
CSn
CLK
DO
AS5040
PROG
100R
CSn
CLK
DO
1nF
GND
AS5040
PROG
100R
1nF
GND
CSn
CLK
DO
AS5040
PROG
GND
Figure 25:
Daisy Chain Mode Data Transfer
CSn
CLK
DO t
CLK FE
T
CLK/2
1
t
DO active
8 16 D 1 2 3
D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
OCF COF LIN
Mag
INC
Mag
DEC
Even
PAR
t
DO valid
Angular Position Data Status Bits
1 st
Device
D9 D8 D7
Angular Position Data
2 nd
Device
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AS5040 −
Incremental Outputs
Incremental Outputs
Three different incremental output modes are possible with quadrature A/B being the default mode.
Figure 26 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.
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.
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
Figure 26:
Incremental Output Modes
Quad A/B-Mode
A
B
Ind ex
Step / Dir-Mode
LSB
Dir
C Sn t
In crem ental outp uts valid
M echanical
Zero Position
Rotation Direction
Change
M echanical
Zero Position
Index=0
1LSB
Index=1
3 LSB
Clockwise cw
H yst =
2 L S B t
D ir valid
Counterclockwise ccw
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AS5040 −
Incremental Outputs
Incremental Power-Up Lock Option
After power-up, the incremental outputs can optionally be locked or unlocked, depending on the status of the CSn pin:
CSn = low at power-up:
CSn has an internal pull-up resistor and must be externally pulled low (R ext
≤ 5k
Ω
). If Csn is low at power-up, the incremental outputs (A, B, Index) will be high until the internal offset compensation is finished.
This unique state (A=B=Index = high) 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 AS5040 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.
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AS5040 −
Incremental Outputs
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
If for example 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 27:
Hysteresis Window for Incremental Outputs
!
0.35°
!
Clockwise Direction
Counterclockwise Direction
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AS5040 −
Pulse Width Modulation (PWM) Output
Pulse Width Modulation (PWM)
Output
The AS5040 provides a pulse width modulated output (PWM), whose duty cycle is proportional to the measured angle.
(EQ1)
Position = t 1025
------------------------t on on
×
+ t off
– 1
The PWM frequency is internally trimmed to an accuracy of
±5% (±10% over full temperature range). This tolerance can be canceled by measuring the complete duty cycle as shown above.
Figure 28:
PWM Output Signal
Angle
0 deg
(Pos 0)
PW
MIN
1μs
359.65 deg
(Pos 1023)
PW
MAX
1/f
PWM
1025μs
1024μs
Figure 29:
PWM Signal Parameters
Parameter
PWM frequency
MIN pulse width
Symbol
f
PWM
PW
MIN
Typ
0.9756
1
MAX pulse width
PW
MAX
1024
Unit
kHz
μ s
μ s
Note
Signal period: 1025
μ s
•
Position 0d
•
Angle 0 deg
•
Position 1023d
•
Angle 359,65 deg
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AS5040 −
Analog Output
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 AS5040 can be used as direct replacement of potentiometers.
Figure 30:
Simple Passive 2 nd
Order RC Low Pass Filter
Pin12
PWM
R1
C1
R2
C2 analog out
VDD
2
0V
2
0°
360°
Pin7
VSS
(EQ2)
R1, R2 ≥ 4K7 C1, C2 ≥ 1
μ
F/6V
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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AS5040 −
Brushless DC Motor Commutation Mode
Brushless DC Motor
Commutation Mode
(EQ3)
Brushless DC motors require angular information for stator commutation. The AS5040 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
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
and
by multiplying each transition position by the angular value of
1 count:
Angle [deg] = Position x (360 degree / 1024)
Figure 31:
U, V and V-Signals for BLDC Motor Commutation (Div1=0, Div0=0)
Commutation - Mode 3.0
(One-pole-pair)
Width: 512 Steps
U
V
W
CW Direction
Position:
Angle:
0
0.0
171
60.12
341
119.88
512
180.0
Width: 512 Steps
683
240.12
853
299.88
0
360.0
Figure 32:
U, V and W-Signals for 2-Pole BLDC Motor Commutation (Div1=1; Div0=0)
Commutation - Mode 3.2
(Two-pole-pairs)
Width: 256 Steps Width: 256 Steps
U
V
W
CW Direction
Position:
Angle:
0
0.0
85
29.88
171
60.12
256
90.0
341
119.88
427
150.12
512
180.0
597
209.88
683
240.12
768
270.00
853
299.88
939
330.12
0
360.0
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AS5040 −
Programming the AS5040
Programming the AS5040
After power-on, programming the AS5040 is enabled with the rising edge of CSn with Prog = high and CLK = low. 16 bit configuration data must be serially shifted into the OTP register via the Prog-pin. The first “CCW” bit is followed by the zero position data (MSB first) and the incremental mode setting as shown in Table 6. Data must be valid at the rising edge of CLK
(see
).
After writing data into the OTP register it can be permanently programmed by rising the Prog pin to the programming voltage
V
PROG
. 16 CLK pulses (t
PROG
) must be applied to program the fuses (
). To exit the programming mode, the chip must be reset by a power-on-reset. The programmed data is available after the next power-up.
Note(s):
During the programming process, the transitions in the programming current may cause high voltage spikes generated by the inductance of the connection cable. To avoid these spikes and possible damage to the IC, the connection wires, especially the signals Prog and VSS must be kept as short as possible. The maximum wire length between the V
PROG switching transistor and pin Prog (see
) should not exceed 50mm (2 inches). To suppress eventual voltage spikes, a 10nF ceramic capacitor should be connected close to pins
Prog and VSS. This capacitor is only required for programming, it is not required for normal operation.
The clock timing t clk
must be selected at a proper rate to ensure that the signal Prog is stable at the rising edge of CLK (see
Figure 33 ). Additionally, the programming supply voltage
should be buffered with a 10
μ
F capacitor mounted close to the switching transistor. This capacitor aids in providing peak currents during programming.
The specified programming voltage at pin Prog is 7.3 – 7.5V (see section 0). To compensate for the voltage drop across the V
PROG switching transistor, the applied programming voltage may be set slightly higher (7.5 - 8.0V, see
OTP Register Contents:
CCW
Z [9:0]
Indx
Counter Clockwise Bit
•
ccw=0 – angular value increases in clockwise direction
•
ccw=1 – angular value increases in counterclockwise direction
Programmable Zero / Index Position
Index Pulse Width Selection: 1LSB / 3LSB
Div1, Div0
Divider Setting of Incremental Output
Md1, Md0
Incremental Output Mode Selection
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AS5040 −
Programming the AS5040
OTP Default Setting
The AS5040 can also be operated without programming. The default, un-programmed setting is shown in
(Mode 0.0):
CCW:0
Z9 to Z0: 00
= Clockwise operation
= No programmed zero position
Indx: 0 = Index bit width = 1LSB
Div0,Div1: 00 = Incremental resolution = 10bit
Md0, MD1: 00 = Incremental mode = quadrature
Figure 33:
Programming Access – Write Data (section of
Figure 34:
Complete Programming Sequence
Write Data
CSn
Data
Prog
CLK
PROG t
Load PROG
1
Programming Mode
16
Power Off
7.5V
VDD
V
ProgOff
0V t
PrgR t
PrgH t
PROG t
PROG finished
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AS5040 −
Programming the AS5040
Figure 35:
OTP Programming Connection of AS5040 (shown with AS5040 demoboard) ams Datasheet
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AS5040 −
Programming the AS5040
Incremental Mode Programming
Three different incremental output modes are available.
Mode: Md1=0 / Md0=1 sets the AS5040 in quadrature mode.
Mode: Md1=1 / Md0=0 sets the AS5040 in step / direction mode (see
).
In both modes, 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
Mode: Md1=1 / Md0=1 sets the AS5040 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 0:0 (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
) allows 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 30000 rpm.
ams Datasheet
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A S 5 0 4 0 −
Programming the AS5040
Figure 36:
One Time Programmable (OTP) Register Options
OTP-Mode-Register-Bit
Mode
Default (Mode0.0) quadAB-Mode1.0 quadAB-Mode1.1 quadAB-Mode1.2 quadAB-Mode1.3 quadAB-Mode1.4 quadAB-Mode1.5 quadAB-Mode1.6 quadAB-Mode1.7
Md1
0
0
0
0
0
0
0
0
0
Md0
0
1
1
1
1
1
1
1
1
Div1
1
1
0
0
0
0
0
1
1
Div0
0
0
1
1
0
0
0
1
1
Index
0
1
0
1
0
0
1
0
1
3
A
4
B
Pin #
6
1LSB
1LSB
3LSBs
1LSB
3LSBs
1LSB
3LSBs
1LSB
3LSBs
12
PWM 10 bit
Pulses per
Revolution ppr
2x256
2x128
2x64
2x32
Incremental
Resolution bit
10
9
8
7
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A S 5 0 4 0 −
Programming the AS5040
OTP-Mode-Register-Bit
Mode
Step/Dir-Mode2.0
Step/Dir-Mode2.1
Step/Dir -Mode2.2
Step/Dir -Mode2.3
Step/Dir -Mode2.4
Step/Dir -Mode2.5
Step/Dir -Mode2.6
Step/Dir -Mode2.7
Commutation-
Mode3.0
Commutation-
Mode3.1
Commutation-
Mode3.2
Commutation-
Mode3.3
Md1
1
1
1
1
1
1
1
1
1
1
1
1
Md0
0
0
0
0
0
0
0
0
1
1
1
1
Div1
1
1
1
1
0
0
0
0
0
0
1
1
1
0
1
Div0
1
1
0
0
1
1
0
0
0
Index
0
1
0
1
0
1
0
1
0
0
0
0
3
LSB
4
Dir
Pin #
U(0º) V(120º) W(240º)
U’ (0º,
180º)
V’ (60º,
240º)
W’ (120º,
300º)
6
1LSB
3LSBs
1LSB
3LSBs
1LSB
3LSBs
1LSB
3LSBs
12
PWM 10 bit
LSB
LSB
Note(s):
1. Div1, Div0 and Index cannot be programmed in Mode 0:0
Pulses per
Revolution ppr
512
256
128
64
3 x 1
2 x 3
Incremental
Resolution bit
10
9
8
7
10
9
10
9
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AS5040 −
Programming the AS5040
ams Datasheet
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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.
This value is written into the OTP register bits Z9:Z0 (see
Figure 33 ) and programmed as described in
This new absolute zero position is also the new Index pulse position for incremental output modes.
Note(s):
The zero position value may also be modified before programming, e.g. to program an electrical zero position that is 180° (half turn) from the mechanical zero position, just add
512 to the value read at the mechanical zero position and program the new value into the OTP register.
Repeated OTP Programming
Although a single AS5040 OTP register bit can be programmed only once (from 0 to 1), it is possible to program other, unprogrammed bits in subsequent programming cycles.
However, a bit that has already been programmed should not be programmed twice. Therefore it is recommended that bits that are already programmed are set to “0” during a programming cycle.
Non-Permanent Programming
It is also possible to re-configure the AS5040 in a non-permanent way by overwriting the OTP register.
This procedure is essentially a “Write Data” sequence (see
Figure 33 ) without a subsequent OTP programming cycle.
The “Write Data” sequence may be applied at any time during normal operation. This configuration remains set while the power supply voltage is above the power-on reset level (see 0).
See Application Note AN5000-20 for further information.
Analog Readback Mode
Non-volatile programming (OTP) uses on-chip zener diodes, which become permanently low resistive when subjected to a specified reverse current.
The quality of the programming process depends on the amount of current that is applied during the programming process (up to 130mA).
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AS5040 −
Programming the AS5040
This current must be provided by an external voltage source. If this voltage source cannot provide adequate power, the zener diodes may not be programmed properly.
In order to verify the quality of the programmed bits, an analog level can be read for each zener diode, giving an indication whether this particular bit was properly programmed or not.
To put the AS5040 in analog readback mode, a digital sequence must be applied to pins CSn, Prog and CLK as shown in
Figure 37 . The digital level for this pin depends on the supply
configuration (3.3V or 5V; see
).
The second rising edge on CSn (OutpEN) changes pin Prog to a digital output and the log. high signal at pin Prog must be removed to avoid collision of outputs (grey area in
The following falling slope of CSn changes pin Prog to an analog output, providing a reference voltage Vref, that must be saved as a reference for the calculation of the subsequent programmed and unprogrammed OTP bits. Following this step, each rising slope of CLK outputs one bit of data in the reverse order as during programming (see
Md0-MD1-Div0,Div1-Indx-Z0…Z9, ccw)
During analog readback, the capacitor at pin Prog (see
Figure 35 ) should be removed to allow a fast readout rate. If the
capacitor is not removed the analog voltage will take longer to stabilize due to the additional capacitance.
The measured analog voltage for each bit must be subtracted from the previously measured V ref
, and the resulting value gives an indication on the quality of the programmed bit: a reading of <100mV indicates a properly programmed bit and a reading of >1V indicates a properly unprogrammed bit.
A reading between 100mV and 1V indicates a faulty bit, which may result in an undefined digital value, when the OTP is read at power-up.
Following the 16th clock (after reading bit “ccw”), the chip must be reset by disconnecting the power supply.
Figure 37:
OTP Register Analog Read
C S n
P ro g E N
P ro g
C L K
O u tp E N
A n a lo g R e a d b a c k D a ta a t P ro g
P o w e r-o n -
R e s e t; tu rn o ff s u p p ly
V re f
V p ro g ra m m e d
In te rn a l te s t b it d ig ita l
M d 0 M d 1 D iv 0 D iv 1 V u n p ro g ra m m e d
Z 5 Z 6 Z 7 Z 8
Z 9 c c w
P ro g c h a n g e s to O u tp u t
1 1 6 t
L o a d P ro g
C L K
A re a d
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AS5040 −
Alignment Mode
Alignment Mode
The alignment mode simplifies centering the magnet over the chip to gain maximum accuracy and XY-alignment tolerance.
This electrical centering method allows a wider XY-alignment tolerance (0.485mm radius) than mechanical centering(0.25mm radius) as it eliminates the placement tolerance of the die within the IC package (+/- 0.235mm).
Alignment mode can be enabled with the falling edge of CSn while Prog = logic high (
Figure 38 ). 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 32 over a full turn.The MagINCn and
MagDECn indicators will be = 1 when the alignment mode reading is < 32. 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 360° turn of the magnet.
Stronger magnets or short gaps between magnet and IC may show values larger than 32. 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 mode by a power-on-reset (disconnect / re-connect power supply).
Figure 38:
Enabling the Alignment Mode
Prog
CSn
AlignMode enable
Read-out via SSI
2μs 2μs min.
min.
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AS5040 −
3.3V / 5V Operation
3.3V / 5V Operation
Figure 39:
Connections for 5V / 3.3V Supply Voltages
The AS5040 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 2.2...10
μ
F capacitor, which is supposed to be placed close to the supply pin (see
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
5V Operation
100n
VDD5V
VDD3V3
LDO
2.2...10μF
Internal
VDD
4.5 - 5.5V
I
N
T
E
R
F
A
C
E
VSS
DO
PWM_LSB
CLK
CSn
A_LSB_U
B_Dir_V
Index_W
Prog
3.3V Operation
VDD3V3
VDD5V
LDO
Internal
VDD
3.0 - 3.6V
I
N
T
E
R
F
A
C
E
VSS
100n
DO
PWM_LSB
CLK
CSn
A_LSB_U
B_Dir_V
Index_W
Prog
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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AS5040 −
Choosing the Proper Magnet
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 gauss-meter. The magnetic field Bv at a given distance, along a concentric circle with a radius of
1.1mm (R1), should be in the range of ±45mT to ±75mT. (see
Figure 40:
Typical Magnet and Magnetic Field Distribution
typ. 6mm diameter
Vertical field component
N
R1
S
Magnet axis
Magnet axis
N S
R1 concentric circle; radius 1.1mm
Vertical field component
Bv
(45…75mT)
0 360
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AS5040 −
Choosing the Proper Magnet
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 41:
Defined IC Center and Magnet Displacement Radius
1
3.9 mm 3.9 mm
2.433 mm
2.433 mm
Defined
center
R
d
Area of recommended maximum magnet misalignment
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ams Datasheet
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AS5040 −
Choosing the Proper Magnet
Figure 42:
Vertical Placement of the Magnet
Magnet Placement
The magnet’s center axis should be aligned within a displacement radius R d
of 0.25mm from the defined center of the IC with reference to the edge of pin #1 (see
radius includes the placement tolerance of the chip within the
SSOP-16 package (± 0.235mm). The displacement radius R d
is
0.485mm with reference to the center of the chip (see
The vertical distance should be chosen such that the magnetic field on the die surface is within the specified limits (see
Figure 40 ). 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
.
N S
Die surface Package surface z
0.576mm ± 0.1mm
1.282mm ± 0.15mm
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Simulation Modelling
Figure 43:
Arrangement of Hall Sensor Array on Chip (principle)
AS5040 −
Simulation Modelling
Page 42
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With reference to
, a diametrically magnetized permanent magnet is placed above or below the surface of the
AS5040. 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.
The angular displacement (θ) of the magnetic source with reference to the Hall sensor array may then be modelled by:
(EQ4)
θ
= arc tan
(
(
Y1
X1
–
–
Y2
X2
)
)
±
0.5
°
The ±0.5° angular error assumes a magnet optimally aligned over the center of the die and is a result of gain mismatch errors of the AS5040. 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 (
).
ams Datasheet
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AS5040 −
Simulation Modelling
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.
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Failure Diagnostics
AS5040 −
Failure Diagnostics
The AS5040 also offers several diagnostic and failure detection features:
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).
Power Supply Failure Detection
By software:
If the power supply to the AS5040 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 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
Figure 22 ). 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 AS5040, 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.
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 t
PwrUp
).
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AS5040 −
Angular Output Tolerances
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 @ 25°C (see
Misalignment of the magnet further reduces the accuracy.
Figure 44 shows an example of a 3D-graph displaying
nonlinearity 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 45 is repeated and the accuracy (Err
max
– Err min
)/2 (e.g.
0.25° in
Figure 45 ) is entered as the Z-axis in the 3D-graph.
Figure 44:
Example of Linearity Error Over XY Misalignment ams Datasheet
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AS5040 −
Angular Output Tolerances
The maximum non-linearity error on this example is better than
±1 degree (inner circle) over a misalignment radius of ~0.7mm.
For volume production, the placement tolerance of the IC within the package (±0.235mm) must also be taken into account.
The total nonlinearity error over process tolerances, temperature and a misalignment circle radius of 0.25mm is specified better than ±1.4 degrees.
The magnet used for this measurement was a cylindrical NdFeB
(Bomatec® BMN-35H) magnet with 6mm diameter and 2.5mm in height.
Figure 45:
Example of Linearity Error Over 360º
Linearity error with centered magnet [degrees]
0.5
0.4
0.3
0.2
0.1
0
Err max transition noise
- 0.1
- 0.2
1 55 109 163 217 271 325 379 433 487 541 595 649 703 757 811 865 919 973
Errmin
- 0.3
- 0.4
- 0.5
Transition Noise
Transition noise is defined as the jitter in the transition between two steps.
Due to the nature of the measurement principle (Hall sensors
+ Preamplifier + ADC), there is always a certain degree of noise involved.
This transition noise voltage results in an angular transition noise at the outputs. It is specified as 0.12 degrees rms (1 sigma)
1
This is the repeatability of an indicated angle at a given mechanical position.
1. Statistically, 1 sigma represents 68.27% of readings,
3 sigma represents 99.73% of readings.
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AS5040 −
Angular Output Tolerances
ams Datasheet
[v2-12] 2017-Jun-20
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.
•
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).
High Speed Operation
Sampling Rate
The AS5040 samples the angular value at a rate of 10.42k samples per second. Consequently, the incremental, as well as the absolute outputs are updated each 96
μ s. At a stationary position of the magnet, this sampling rate creates no additional error.
Absolute Mode with Serial Communication
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:
(EQ5)
n = rpm 96
μ s
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:
(EQ6)
rpm =
-------------------n 96
μ s
In absolute mode with serial communication, 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/+96
μ s. It has a peak of
1LSB = 0.35° at 610 rpm. At higher speeds this error is reduced again due to interpolation and the output delay remains at
192
μ s as the DSP requires two sampling periods (2x96
μ s) to synthesize and redistribute any missing pulses.
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Figure 46:
Speed Performance
Absolute Output Mode
610rpm = 1024 samples / turn
1220rpm = 512 samples / turn
2441rpm = 256 samples / turn etc…
AS5040 −
Angular Output Tolerances
Absolute Mode with PWM
The principle is the same as with the serial communication. The
PWM output is refreshed with a rate of 1.025ms, the number of samples (n) per turn for a magnet rotating at high speed can be calculated by:
(EQ7)
n =
------------------------------------rpm
×
1.025ms
In absolute mode with PWM output, 57 rpm is the maximum speed, where 1024 readings per revolution can be obtained.
Incremental Mode
Incremental encoders are usually required to produce no missing pulses up to several thousand rpm’s.
Therefore, the AS5040 has a built-in interpolator, which ensures that there are no missing pulses at the incremental outputs for rotational speeds of up to 30000 rpm, even at the highest resolution of 10 bits (512 pulses per revolution).
Incremental Output Mode
No missing pulses
@ 10 bit resolution (512ppr): max. speed = 30000 rpm
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 48
μ s for the absolute interface and 192
μ s 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/f s
) and the time it takes the external control unit to read and process the data.
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ams Datasheet
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AS5040 −
Angular Output Tolerances
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:
(EQ8)
e sampling
= rpm
×
6
×
Where: e sampling
= 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 AS5040, thus reducing the angular error caused by speed.
Internal Timing Tolerance
The AS5040 does not require an external ceramic resonator or quartz. All internal clock timings for the AS5040 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 100
μ s (typ)
•
Incremental outputs: the incremental outputs are updated every 100
μ s (typ.)
•
PWM output:
A new angular value is updated every 100
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 canceled by measuring both T on
and T off and calculating the angle from the duty cycle (see
(EQ9)
Position =
( t 1025
-------------------------t on on
⋅
+ t off
)
– 1
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AS5040 −
Angular Output Tolerances
Temperature
Magnetic Temperature Coefficient
One of the major benefits of the AS5040 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 AS5040 automatically compensates for the varying magnetic field strength over temperature. The magnet’s temperature drift does not need to be considered, as the AS5040 operates with magnetic field strengths from ±45mT to ±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 AS5040 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 ≤ ±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 canceled by measuring the complete PWM duty cycle (see
).
ams Datasheet
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AS5040 −
Mechanical Data
Mechanical Data
Figure 47:
Hall Element Positions
The internal Hall elements are located in the center of the package on a circle with a radius of 1 mm.
Note(s):
1. All dimensions in mm.
2. Die thickness 381
μ m nom.
3. Adhesive thickness 30 ± 15
μ m.
4. Leadframe downset 200 ± 38
μ m.
5. Leadframe thickness 152±8
μ m.
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Package Drawings & Markings
Figure 48:
16-Lead Shrink Small Outline Package SSOP-16
AS5040 −
Pack age Drawings & Mark ings
Symbol Min Typ Max
c 0.09 0.20 e 0.65
L1
L2
R 0.09
Θ
0º
N
1.25 REF
0.25 BSC
16
-
4º
-
8º
Note(s):
1. Dimensioning and tolerancing conform to ASME Y14.5M-1994.
2. All dimensions are in millimeters. Angles in degrees.
3. N is the total number of terminals.
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RoHS
Green
ams Datasheet
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AS5040 −
Package Drawings & Markings
Figure 49:
Package Marking
Figure 50:
Packaging Code
YY
Last two digits of the manufacturing year
WW M
Manufacturing week Plant identifier
ZZ
Free choice/ traceability code
@
Sublot identifier
JEDEC Package Outline Standard:
MO - 150 AC
Thermal Resistance R th(j-a)
: typ. 151 K/W in still air, soldered on PCB
IC's marked with a white dot or the letters
"ES" denote Engineering Samples
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AS5040 −
Recommended PCB Footprint
Recommended PCB Footprint
Figure 51:
Recommended PCB Footprint
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Figure 52:
Recommended Footprint Data
Recommended Footprint Data mm
A 9.02
B 6.16
C 0.46
D 0.65
E 5.01
inch
0.355
0.242
0.018
0.025
0.197
ams Datasheet
[v2-12] 2017-Jun-20
AS5040 −
Ordering & Contact Information
Ordering & Contact Information
Figure 53:
Ordering Information
Ordering Code
AS5040-ASSM
AS5040-ASST
Package
SSOP-16
SSOP-16
Marking
AS5040
AS5040
Delivery Form
Tape & Reel
Tape & Reel
Delivery Quantity
500 pcs/reel
2000 pcs/reel
Buy our products or get free samples online at: www.ams.com/ICdirect
Technical Support is available at: www.ams.com/Technical-Support
Provide feedback about this document at: www.ams.com/Document-Feedback
For further information and requests, e-mail us at: [email protected]
For sales offices, distributors and representatives, please visit: www.ams.com/contact
Headquarters
ams AG
Tobelbader Strasse 30
8141 Premstaetten
Austria, Europe
Tel: +43 (0) 3136 500 0
Website: www.ams.com
ams Datasheet
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AS5040 −
RoHS Compliant & ams Green Statement
RoHS Compliant & ams Green
Statement
RoHS:
The term RoHS compliant means that ams AG products fully comply with current RoHS directives. Our semiconductor products do not contain any chemicals for all 6 substance categories, including the requirement that lead not exceed
0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, RoHS compliant products are suitable for use in specified lead-free processes.
ams Green (RoHS compliant and no Sb/Br):
ams Green defines that in addition to RoHS compliance, our products are free of Bromine (Br) and Antimony (Sb) based flame retardants
(Br or Sb do not exceed 0.1% by weight in homogeneous material).
Important Information:
The information provided in this statement represents ams AG knowledge and belief as of the date that it is provided. ams AG bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. ams AG has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. ams AG and ams AG suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.
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AS5040 −
Copyrights & Disclaimer
Copyrights & Disclaimer
Copyright ams AG, Tobelbader Strasse 30, 8141 Premstaetten,
Austria-Europe. Trademarks Registered. All rights reserved. The material herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner.
Devices sold by ams AG are covered by the warranty and patent indemnification provisions appearing in its General Terms of
Trade. ams AG makes no warranty, express, statutory, implied, or by description regarding the information set forth herein. ams AG reserves the right to change specifications and prices at any time and without notice. Therefore, prior to designing this product into a system, it is necessary to check with ams AG for current information. This product is intended for use in commercial applications. Applications requiring extended temperature range, unusual environmental requirements, or high reliability applications, such as military, medical life-support or life-sustaining equipment are specifically not recommended without additional processing by ams AG for each application. This product is provided by ams AG “AS IS” and any express or implied warranties, including, but not limited to the implied warranties of merchantability and fitness for a particular purpose are disclaimed.
ams AG shall not be liable to recipient or any third party for any damages, including but not limited to personal injury, property damage, loss of profits, loss of use, interruption of business or indirect, special, incidental or consequential damages, of any kind, in connection with or arising out of the furnishing, performance or use of the technical data herein. No obligation or liability to recipient or any third party shall arise or flow out of ams AG rendering of technical or other services.
ams Datasheet
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AS5040 −
Document Status
Document Status
Document Status
Product Preview
Preliminary Datasheet
Datasheet
Datasheet (discontinued)
Product Status
Pre-Development
Pre-Production
Production
Discontinued
Definition
Information in this datasheet is based on product ideas in the planning phase of development. All specifications are design goals without any warranty and are subject to change without notice
Information in this datasheet is based on products in the design, validation or qualification phase of development.
The performance and parameters shown in this document are preliminary without any warranty and are subject to change without notice
Information in this datasheet is based on products in ramp-up to full production or full production which conform to specifications in accordance with the terms of ams AG standard warranty as given in the General Terms of
Trade
Information in this datasheet is based on products which conform to specifications in accordance with the terms of ams AG standard warranty as given in the General Terms of
Trade, but these products have been superseded and should not be used for new designs
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AS5040 −
Revision Information
Revision Information
Changes from 2-11 (2015-Nov-20) to current revision 2-12 (2017-Jun-20)
Updated text under Incremental Mode Programming
Updated Figure 53
Note(s):
1. Page and figure numbers for the previous version may differ from page and figure numbers in the current revision.
2. Correction of typographical errors is not explicitly mentioned.
Page
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Content Guide
Page 60
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AS5040 −
Content Guide
1 General Description
2 Key Benefits & Features
2 Applications
3 Block Diagram
4 Pin Assignment
4 Pin Description
5 Mode 1.x: Quadrature A/B Output
5 Mode 2.x: Step / Direction Output
5 Mode 3.x: Brushless DC Motor Commutation Mode
7 Absolute Maximum Ratings
8 Electrical Characteristics
8 Operating Conditions
8 DC Characteristics for Digital Inputs and Outputs
8 CMOS Schmitt-Trigger Inputs: CLK, CSn
(CSn = Internal Pull-Up)
9 CMOS / Program Input: Prog
9 CMOS Output Open Drain: MagINCn, MagDECn
10 CMOS Output: A, B, Index, PWM
10 Tristate CMOS Output: DO
11 Magnetic Input Specification
12 Electrical System Specifications
14 Timing Characteristics
14 Synchronous Serial Interface (SSI)
15 Pulse Width Modulation Output
15 Incremental Outputs
16 Programming Conditions
17 Functional Description
18
18 10-Bit Absolute Angular Position Output
18 Synchronous Serial Interface (SSI)
18 Data Content
21 Daisy Chain Mode
21 Programming Daisy Chained Devices
23 Incremental Outputs
23 Quadrature A/B Output (Quad A/B Mode)
23 LSB Output (Step/Direction Mode)
24 Incremental Power-Up Lock Option
25 Incremental Output Hysteresis
26 Pulse Width Modulation (PWM) Output
27 Analog Output
28 Brushless DC Motor Commutation Mode
29 Programming the AS5040
30 OTP Default Setting
32 Incremental Mode Programming
35 Zero Position Programming
35 Repeated OTP Programming
35 Non-Permanent Programming
ams Datasheet
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AS5040 −
Content Guide
35 Analog Readback Mode
37 Alignment Mode
38 3.3V / 5V Operation
39 Choosing the Proper Magnet
40 Physical Placement of the Magnet
41 Magnet Placement
42 Simulation Modelling
44 Failure Diagnostics
44 Magnetic Field Strength Diagnosis
44 Power Supply Failure Detection
45 Angular Output Tolerances
45 Accuracy
46 Transition Noise
47 High Speed Operation
47 Sampling Rate
47 Absolute Mode with Serial Communication
48 Absolute Mode with PWM
48 Incremental Mode
48 Propagation Delays
49 Angular Error Caused by Propagation Delay
49 Internal Timing Tolerance
50 Temperature
50 Magnetic Temperature Coefficient
50 Accuracy Over Temperature
50 Timing Tolerance Over Temperature
51 Mechanical Data
52 Package Drawings & Markings
54 Recommended PCB Footprint
55 Ordering & Contact Information
56 RoHS Compliant & ams Green Statement
57 Copyrights & Disclaimer
58 Document Status
59 Revision Information
ams Datasheet
[v2-12] 2017-Jun-20
Page 61
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Key features
Contactless, high-resolution rotational position encoding
User-programmable resolution, pole pairs, and zero position
Multiple interfaces: SSI, PWM, Quadrature A/B, Step/Direction, 3-Phase
Ideal for motor applications with speeds up to 30000 rpm
Failure detection mode for magnet placement and power loss monitoring
AEC-Q100 qualified for automotive applications
Small form factor SSOP 16 package
Wide temperature range: -40°C to 125°C
Frequently asked questions
The AS5040 supports Serial communication interface (SSI), 10-bit pulse width modulated (PWM) output, Quadrature A/B and Index output signal, Step/Direction and Index output signal, and 3-Phase commutation for brushless DC motors.
AS5040 is ideal for industrial applications such as contactless rotary position sensing and robotics, and automotive applications such as steering wheel/gas pedal position sensing.
The absolute angle measurement provides instant indication of the magnet’s angular position with a resolution of 0.35° = 1024 positions per revolution.
