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AS5040 10-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER
AS5040 10 BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER Key Features
Contact-less high resolution encoding over a full turn of 360 degrees Flexible system due to user programmable incremental output modes: 10, 9, 8 or 7 bit user programmable resolution Quadrature A/B and index output signal Single channel output and direction indication U-V-W commutation signals for brush-less DC motors Absolute angular position mode: 10-bit resolution providing 1024 absolute positions per 360 degrees (step size ~ 0.35 deg) Synchronous serial interface (SSI) output for absolute position data Pulse width modulated (PWM) output, duty cycle proportional to angle User programmable zero / index position Failure detection mode for magnet placement monitoring Rotational speeds up to 10,000 rpm (incremental output) Push button functionality detects movement of magnet in Z-axis Two supply voltages: Wide temperature range: Small package: 3.3 V or 5 V - 40C to + 125C SSOP 16 (5.3mm x 6.2mm)
Figure 1: Typical arrangement AS5040 and magnet
DATA SHEET
General Description
The AS5040 is a system-on-chip, combining integrated Hall elements, analog front end and digital signal processing in a single device. It provides incremental output signals and the absolute angular position of a magnet that is placed either above or below the device. The AS5040 can be configured to specific customer requirements by programming the integrated OTP (one time programmable) register. An internal voltage regulator allows the AS5040 to operate at either 3.3 V or 5 V supplies.
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Benefits
World's smallest multiple output magnetic rotary encoder Tolerant to magnetic source misalignment Failure detection feature Complete system-on-chip: Flexible system solution provides absolute, incremental and PWM digital outputs simultaneously minimum number of external components needed Serial read-out of multiple AS5040 devices using daisy chain mode Ideal for applications in harsh environments due to contact-less position sensing
Applications
Industrial applications such as: Motion control Robotics Brush-less 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 Office equipment: printers, scanners, copiers Replacement of optical encoders Front panel rotary switches and potentiometers
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AS5040 10-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER
Pin Configuration
Pin
MagINCn MagDECn A_LSB_U B_Dir_V NC Index_W VSS Prog
1 2 16 15
Symbol
MagINCn
Type
DO_OD
Description
Magnet Field Magnitude INCrease; active low, indicates a distance reduction between the magnet and the device surface. Magnet Field Magnitude DECrease; active low, indicates a distance increase between the device and the magnet. Mode1: Quadrature A channel Mode2: Least Significant Bit Mode3: U signal (phase1) Mode1: Quadrature B channel quarter period shift to channel A. Mode2: Direction of Rotation Mode3: V signal (phase2) must be left unconnected Mode1 and Mode2 : Index signal indicates the absolute zero position Mode3: W signal (phase3) Negative Supply Voltage (GND) Programming and Data Input for Mode configuration, incremental resolution setting, Zero-Position Programming and Daisy Chain mode configuration. Internal pulldown resistor (~74k) Data Output of Synchronous Serial Interface Clock Input of Synchronous Serial Interface; Schmitt-Trigger input Chip Select, active low; SchmittTrigger input, internal pull-up resistor (~50k) Pulse Width Modulation of approx. 1kHz; LSB in Mode3 must be left unconnected must be left unconnected 3V-Regulator Output Positive Supply Voltage 5 V
VDD5V VDD3V3 NC NC PWM_LSB CSn CLK DO
3 4 5 6 7 8
14 13 12 11 10 9
1
Figure 2: Pin configuration SSOP16
AS5040
2
MagDECn
DO_OD
3
A_LSB_U
DO
4
B_Dir_V NC Index_ W VSS
DO DO S
Pin Description
Table 2 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). 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: Output mode 01 quadrature 02 single channel 03 commutation Pin3 A LSB U Pin4 B direction V Pin6 Index Index W Pin12 PWM PWM LSB
5 6 7
8
Prog
DI_PD
9 10
DO CLK
DO_T DI, ST DI_PU, ST DO S S
11 12 13 14 15 16
CSn PWM_LSB NC NC VDD3V3 VDD5V
Table 1: pin assignment for the different incremental output modes
Table 2: Pin description SSOP16 DO_OD DO DI_PD DI_PU digital digital digital digital output open drain output input pull-down input pull-up S DI DO_T ST supply pin digital input digital output /tri-state schmitt-trigger input
Mode1 - Quadrature A/B output: Represents the default quadrature A/B signal mode. Mode2 - Single channel output: Configures Pin 3 to deliver up to 512 pulses (up to 1024 state changes) per revolution. It is equivalent to the statechange of the LSB (least significant bit) of the absolute position value. Pin 4 provides the information of the rotational direction. Both modes (mode 1 and mode 2) provide an index signal (1 pulse/revolution) with an adjustable width of one LSB or three LSBs.
Mode3 - Brush-less DC motor commutation mode: The alternative third mode provides commutation signals for electrical motors with either one pole pair or two pole pairs. In this mode Pin 12 provides the LSB output instead of the PWM (Pulse-Width-Modulation) signal. Pin 8 (Prog) can be used as digital input to shift serial data through the device (Daisy Chain Configuration). This pin is also necessary to program the different interface modes, the incremental resolution and the zero-position into the O(SSI) to readout the absolute position data of the magnet.
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AS5040 10-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER
Pin 11 Chip Select (CSn; active low) selects a device within a network of AS5040 encoders. A "logic high" at CSn forces the digital tri-state output into the high ohmic state. A "high" pulse with a minimum duration of tCSn also initiates a subsequent readout of the current angular value. Pin 12 allows a single wire output of the 10bit absolute position value. The value is encoded into a pulse width modulated signal ((absolute position code + 1) s). By using an external low pass filter, the PWM angular position output can be converted to an analog voltage, making a direct replacement of potentiometers possible.
The DSP is also used to provide digital information at the outputs M a g I N C n and M a g D E C n 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 15). 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). This PWM signal output also allows the generation of a direct proportional analogue voltage, by using an external LowPass-Filter. 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 according to Table 7. As long as no programming voltage is applied at pin PROG, the new setting can 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 zapped (see Figure 12). The default setting represents the quadrature A/B mode including the Index signal with a pulse width of 1 LSB. The Index signal is logic high at the user's programmed position. The AS5040 is tolerant to magnet misalignment and magnetic stray fields due to differential measurement technique and Hall sensor conditioning circuitry.
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.
MagINCn MagDECn Sin Ang CSn
DSP Hall Array & Frontend Amplifier
Cos Mag
Absolute Interface (SSI)
DO PWM_LSB CLK
OTP Register
A_LSB_U
Programming Parameters
Incremental Interface
B_Dir_V Index_W
Prog
Revision 1.1
Figure 3 AS5040 Block Diagram www.austriamicrosystems.com
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AS5040 10-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER
10 bit Absolute Angular Position Output
Synchronous Serial Interface SSI
CSn t CLK FE T CLK / 2
1 8 16
t CSn
t CLK FE
CLK
1
DO
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
OCF
COF
LIN
M ag IN C
Ma g Even DE C PAR
D9
t DO active
t DO valid
Angular position data
Status bits
t DO Tristate
Figure 4: ynchronous serial interface with absolute angular position data
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. 1. 2. 3. 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 "high" pulse at CSn with a minimum duration of tCSn.
MagINC, (Magnitude Increase) becomes HIGH, when the magnet is pushed towards the IC, thus the magnetic field strength is increasing. MagDEC, (Magnitude Decrease) 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 Table 3). PAR Even Parity bit for transmission error detection of bits 1...13 (D9...D0,OCF,COF,LIN)
Ma g INC 0 0
MagDEC 0 1 0
Description No distance change Magnetic Input Field OK Distance increase (Push-Release) Distance decrease (Push-Fn) Magnetic Input Field invalid - out of range too large, too small (Missing magnet)
4.
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 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 his 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.
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1
1
1
Table 3: Magnetic magnitude variation indicator
Note: Pin 1 (MagINCn) and Pin 2 (MagDECn) are active low via open drain output.
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.
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AS5040 10-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER
Angle
Data D0:D0 is valid, when the status bits have the following configurations: OCF COF LIN Mag INC 0 1 0 0 0 1 Mag DEC 0 1 0 even checksum of bits 1:13 Parity
PWMIN
0 deg (Pos 0)
1s 1025s
PWMAX 359,65 deg (Pos 1023)
1024s
Table 4: status bit outputs
The absolute angular position is sampled at a rate of 10 (0.1ms). This allows reading out all 1024 positions per degrees within 0.1 seconds (9.76 Hz) without skipping position. By multiplying 10Hz by 60, one obtains corresponding maximum rotational speed of 585.9 rpm.
kHz 360 any the
P a r a m e te r
1/fPWM 5%
Figure 5: PWM output signal
Symbol
Typ
Unit
Note
If skipping every second absolute angular position would be acceptable for specific applications, one could increase the rotational speed of the magnet source by a factor of two. Thus speeds of 1200 rpm would be achievable. Readout of every absolute angular position allows for rotational speeds of up to 600rpm Readout of every second angular position allows for rotational speeds of up to 1200rpm Consequently increasing the rotational speed diminishes the number of absolute angular positions to be read out (see Table 6). 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 10,000rpm without missing pulses.
PWM frequency MIN pulse width MAX pulse width
fPWM PWMIN PWMAX
0.9756 1 1024
kHz s s
Signal period: 1025 s - Position 0d - Angle 0 deg - Position 1023d - Angle 359,65 deg
Table 5: PWM signal parameters
Generating an Analog Output This can be achieved by averaging the PWM signal, using an external active or passive low pass filter. This method generates an analogue output signal that is proportional to the measured angle. Thus the device can be used as direct replacement of potentiometers with an analogue voltage output.
Incremental Outputs
Three different incremental output modes are possible with Quadrature A/B being the default mode. Figure 6 shows the two-channel quadrature as well as the single channel incremental signal (LSB) and the direction bit in clockwise (CW) and counter-clockwise (CCW) direction.
10bit Pulse Width Modulation Output
The AS5040 provides a pulse width modulated output (PWM), whose duty cycle is proportional to the measured angle:
Quadrature A / B Output (quad AB 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, magnet placed above or below the device) with 90 electrical degrees. Channel B leads channel A at a counter-clockwise rotation.
Position =
t on 1025 (ton + toff ) - 1
The PWM frequency is internally trimmed to an accuracy of 5%. This tolerance can be cancelled by measuring the complete duty cycle as shown above.
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AS5040 10-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER
Single Channel Output (LSB / Dir Mode)
Output LSB reflects the LSB (least significant bit) of the actual 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, single channel) 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 7).
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. 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 10,000 rpm, even at the highest resolution of 10bits (256 pulses per revolution).
High Speed Operation
Absolute mode: The AS5040 has an internal sampling rate of 10kHz. Consequently, it will sample the angle of the magnet every 100s. Given this value, for a magnet rotating at high speed, the number of samples (n) per turn can be calculated by Absolute Output Mode
586 rpm = 1024 samples / turn 1172 rpm = 512 samples / turn 2343 rpm = 256 samples / turn etc...
Incremental Output Mode
no missing pulses @ 10bit resolution (256ppr): max. speed = 10,000 rpm
Table 6: Speed performance
60 n= rpm * 100 s
Quad A/B-Mode
A B
mechanical zero position
Rotation Direction Change
mechanical zero position
Index=0 1LSB
Index
Hyst = 2 LSB
LSB / Dir-Mode
LSB Dir
Index=1 3 LSB
clockwise cw
counterclockwise ccw
CSn
t Incremental outputs valid
Figure 6: Incremental Output Modes Revision 1.1 www.austriamicrosystems.com
t Dir valid
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AS5040 10-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER
Incremental output hysteresis
To avoid flickering incremental outputs at a stationary magnet position, a hysteresis is introduced.
Incremental output indication X +4 X +3 X +2 X +1 X
X X +1 X +2 X +3 X +4 X +5 Clockwise direction Magnet position
Hysteresis: 2 LSB
Counter clockwise direction
Figure 7: Hysteresis window for incremental outputs
In case of any change of the rotational direction, the incremental outputs have a hysteresis of 2 LSB (1LSB upon request). 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 constant rotational directions, every magnet position change is indicated at the incremental outputs (Figure 7). 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. After this transition, the incremental outputs directly indicate every new position, while the rotational direction is constant.
Daisy Chain Mode
It is possible to connect several AS5040's in series, while reading them by just one serial data line. This socalled "daisy-chain" 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 last device in the chain. The length of the serial bit stream increases with every connected device, it is n x (16+1) bits: e.g 34bit for two devices, 51bit for three devices,etc... The last data bit of the first device (Parity) is followed by a logic "0" and the first data bit of the second device (D9), etc..
C
Data IN
AS5040
DO PROG
AS5040
DO PROG
AS5040
DO PROG
CSn CLK CSn
CLK
CSn
CLK
CSn
CLK
Figure 8: Daisy Chain Mode configuration
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AS5040 10-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER
Brush-less DC Motor Commutation Mode
Brush-less DC motors require angular information for current commutation purposes. The AS5040 provides UV-W commutation signals for one and two pole pair motors. In addition to the three-phase output signals the single channel (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 7. 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 9 and Figure 10) is calculated by multiplying each transition position by the angular value of 1 count: Angle [deg] = Position x (360 degree / 1024)
Commutation - Mode 3.0
Width: 512 Steps
(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
683
240,12
853
299,88
0
360,0
Figure 9: U, V and W-signals for BLDC motor commutation (Div1 = 0; Div0 = 0)
Commutation - Mode 3.2
Width: 256 Steps
(Two-pole-pairs)
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
Figure 10: U, V and W-signals for 2 pole BLDC motor commutation (Div1=1; Div0 = 0)
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AS5040 10-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER
Programming the AS5040
After power-on, programming the AS5040 is enabled at the rising edge of CSn with Prog = logic high. 16 bit configuration data must be serially written 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. Data must be valid at the rising edge of CLK (Figure 11). After writing the data into the OTP register it can be permanently programmed ("zapped") by rising the Prog pin to the programming voltage VPROG. 16 accurate CLK pulses (tPROG) must be applied to program the fuses (Figure 12). The programmed data is available after the next power-on.
OTP Register Content: CCW
Counter Clockwise Bit
CCW=0 - angular value increases in clockwise direction CCW=1 - angular value increases in counter clockwise direction
Z [9:0] Indx Div1,Div0 Md1, Md0
Programmable Zero / Index Position Index Pulse Width Selection Divider Setting of Incremental Output Incremental Output Mode Selection
CSn Prog CLKPROG
t Data in
CCW Z9
Z8
Z7
Z6
Z5
Z4
Z3
Z2
Z1
Z0 Indx Div1 Div0 Md1 Md0 16
1 Zero / Index Position
Incremental Modes
t Prog enable t Data in valid
Figure 11: Programming Access - Write Data
W r ite D a ta CSn
P r o g r a m m in g M o d e
P o w e r O ff
V P ro g CLK D a ta t
PROG PROG
PROG
1
16
t
Load P R O G
t
P R O G f i n is h e d
Figure 12: Programming Access - Zapp Data
Zero Position Programming
Any 10bit angular position can be defined as the zero/index position. It may be used in several applications in order to simplify assembly. For Zero Position Programming, the magnet must be brought to the mechanical zero position of the system (e.g. the "off"position of a rotary switch). The orientation (north/south pole) of the magnet does not need to be considered.
Revision 1.1
The mechanical zero position can be read out via the SSI and be assigned as new zero position Z[9:0] and programmed into the OTP register. This new absolute zero position at the same time also represents the Index pulse position for incremental output modes.
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AS5040 10-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER
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 single channel mode with direction indicator (see Table 1 ) In both modes the incremental resolution can be reduced from 10 bit down to 9, 8 or 7 bit using the divider OTP bits Div1 and Div0. Md0 or Md1 must additionally set for that purpose. 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 facatory setting is all bits = 0. This mode is equal to mode 1:0 (quadrature AB, 1LSB index width, 256ppr). The absolute angular output value, by default, increases if the magnet, placed either above or below the chip, turns clockwise (top view). Setting the CCW-bit (see
Figure 11) 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 counter clockwise). By default, the zero / index position pulse is one LSB wide. However, it can be increased to a three LSB wide pulse by setting the Index-bit of the OTP Register. This is especially useful for high speed operation, where the index signal output may be just a small glitch otherwise. Especially for brush-less DC motor-control, further programmable options are available (CommutationModes), are available. 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 single-pole (Div1=0) or twopole pair (Div1=1) motor operation. In addition, the LSB is available at pin 12 (the LSB signal replaces the PWMsignal), which allows for high rotational speed measurement of up to 10,000 rpm.
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 LSB/Dir-Mode2.0 LSB/Dir-Mode2.1 LSB/Dir -Mode2.2 LSB/Dir -Mode2.3 LSB/Dir -Mode2.4 LSB/Dir -Mode2.5 LSB/Dir -Mode2.6 LSB/Dir -Mode2.7 Commutation-Mode3.0 Commutation-Mode3.1 Commutation-Mode3.2 Commutation-Mode3.3
PIN # 3 4 6
1LSB 1LSB 3LSBs 1LSB A B 3LSBs 1LSB 3LSBs 1LSB 3LSBs 1LSB 3LSBs 1LSB LSB Dir 3LSBs 1LSB 3LSBs 1LSB 3LSBs U(0) U' (0, 180) V(120) W(240) LSB LSB PWM 10bit PWM 10bit
Pulses per Incremental Revolution Resolution 12 ppr bit
Md1
0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1
Md0
0 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1 1
Div1
0* 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 1 1
Div0
0* 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 1 0 1
Inde x
0* 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 0 0 0
2x256
10
2x128 2x64 2x32 512 256 128 64 3x1 2x3
9 8 7 10 9 8 7 10 9 10 9
V' W' (60,240) (120,300)
Table 7: One Time Programmable (OTP) register options
.*Note: Div1,Div0 and Index cannot be programmed in Mode 0:0
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AS5040 10-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER
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 (Figure 13). The Data bits D9-D0 of the SSI change to a 10bit displacement amplitude output. The magnet is properly aligned, when the reading is =< 32 at all rotation angles. The larger the value, the further the magnet is off-center at that particular angle. The MagINCn and MagDECn indicators will be = 1 when the alignment mode reading is > 32. A properly aligned magnet will produce a MagINCn = MagDECn = 0 signal throughout a full 360 turn of the magnet. The Alignment mode can be reset to normal operation mode by a power-on-reset (disconnect / re-connect power supply).
5V Operation
1...10F
VDD3V3
100n
VDD5V
LDO
Internal VDD DO
4.5 - 5.5V
I N T E R F A C E
PWM_LSB CLK CSn A_LSB_U B_Dir_V Index_W Prog
VSS
PROG CSn
AlignMode Enable
Read-out via SSI
3.3V Operation
VDD3V3
100n
VDD5V
LDO
Internal VDD DO
2s 2s min. min.
3.0 - 3.6V
Figure 13: Enabling the alignment mode
3.3V / 5V Operation
The AS5040 operates either at 3.3V 10% or at 5V 10%. This is made possible by an internal 3.3V LowDropout (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 14). For 5V operation, the 5V supply is connected to pin VDD5V, while VDD3V3 (LDO output) must be buffered by a 1...10F capacitor, which is supposed to be placed close to the supply pin (see Figure 14). 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 14).
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I N T E R F A C E
PWM_LSB CLK CSn A_LSB_U B_Dir_V Index_W Prog
VSS
Figure 14: Connections for 5V / 3.3V supply voltages
A buffer capacitor of 100nF is recommended in both cases close to pin VDD5V.
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AS5040 10-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER
Choosing the proper magnet
Typically the magnet should be 6mm in diameter and 3mm in height. Magnetic materials such as rare earth AlNiCo/SmCo5 or NdFeB are recommended.
Physical Placement of the Magnet
The best linearity can be achieved by placing the magnet according to the drawing below. 3.9 mm
1
3.9 mm
The magnetic field strength perpendicular to the die surface has to be in the range of 45mT...75mT (peak). 2.433 mm The magnet's field strength 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...75mT. (see Figure 15).
typ. 6mm diameter
Defined center
0.25 mm 2.433 mm
Rd
Figure 16: Defined center and displacement radius Rd
N
S
Magnet placement:
Magnet axis R1
Magnet axis
The magnet's axis should be aligned within a radius Rd of 0.25mm (displacement radius Rd) with respect to the defined center of the IC. The magnet may be placed below or above the device. The distance should be chosen such that the magnetic field on the die surface is within the specified limits (see Figure 15). The typical distance "z" between the magnet and the package surface is 0.5 mm to 1.5mm, provided the use of the recommended magnet material and dimensions (6mm x 3mm). Larger distances are possible, as long as the required magnetic field strength stays within the defined limits. However, 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 2.
Vertical field component
R1 concentric circle; radius 1.1mm Vertical field component Bv (45...75mT)
0
360
360
N
Die surface
S
Package surface
Figure 15: Typical magnet (6x3mm) and magnetic field distribution
z
0.576mm 0.1mm 1.282mm 0.15mm
Figure 17: Vertical placement of the magnet
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AS5040 10-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER
Electrical Characteristic
Absolute Maximum Ratings (non operating)
Stresses beyond those listed under "Absolute Maximum Ratings" 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 under "Operating Conditions" is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
Parameter
DC supply voltage at pin VDD5V DC supply voltage at pin VDD3V3 Input pin voltage Input current (latchup immunity) Electrostatic discharge Storage temperature Body temperature (Lead-free package) Humidity non-condensing
Symbol
VDD5V VDD3V3 Vin Iscr ESD Tstrg TBody H
Min
-0.3
Max
7 5
Unit
V V V mA kV
Note
-0.3 -100 1 -55
VDD5V +0.3 100
Norm: Jedec 17 Norm: MIL 883 E method 3015 Min - 67F ; Max +257F t=20 to 40s, Norm: IPC/JEDEC J-Std-020B Lead finish 100% Sn "matte tin"
125 250
C C %
5
85
Operating Conditions
Parameter
Ambient temperature Supply current Supply voltage at pin VDD5V Voltage regulator output voltage at pin VDD3V3 Supply voltage at pin VDD5V Supply voltage at pin VDD3V3
Symbol
Tamb Isupp VDD5V VDD3V3 VDD5V VDD3V3
Min
-40
Typ Max
125 16 25 5.5 3.6 3.6 3.6
Unit
C mA V V V V
Note
-40F...+257F
4.5 3.0 3.0 3.0
5.0 3.3 3.3 3.3
5V Operation 3.3V Operation (pin VDD5V and VDD3V3 connected)
DC Characteristics for Digital Inputs and Outputs
CMOS Schmitt-Trigger Inputs: CLK, CSn. (CSn= internal Pull-up)
Parameter
High level input voltage Low level input voltage Schmitt Trigger hysteresis Input leakage current Pullup low level input current
Symbol
VIH VIL VIon- VIoff ILEAK IiL
Min
0.7 * VDD5V
Max
0.3 * VDD5V
Unit
V V V
Note
normal operation
1 -1 -30 1 -100
A A
CLK only CSn only, VDD5V: 5.0V
CMOS / Program Input: Prog
Parameter
High level input voltage High level input voltage Low level input voltage Pulldown high level input current
Symbol
VIH VPROG VIL IiL
Min
0.7 * VDD5V
Max
5 0.3 * VDD5V 100
Unit
V V V A
Note
during programming VDD5V: 5.5V
see "programming conditions"
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AS5040 10-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER
CMOS Output Open Drain: MagINCn, MagDECn
Parameter
Low level output voltage Output current Open drain leakage current
Symbol
VOL IO IOZ
Min
Max
VSS+0.4 4 2 1
Unit
V mA A
Note
VDD5V: 4.5V VDD5V: 3V
CMOS Output: A, B, Index, PWM
Parameter
High level output voltage Low level output voltage Output current
Symbol
VOH VOL IO
Min
VDD5V-0.5
Max
VSS+0.4 4 2
Unit
V V mA mA
Note
VDD5V: 4.5V VDD5V: 3V
Tristate CMOS Output: DO
Parameter
High level output voltage Low level output voltage Output current Tri-state leakage current
Symbol
VOH VOL IO IOZ
Min
VDD5V -0.5
Max
VSS+0.4 4 2 1
Unit
V V mA mA A
Note
VDD5V: 4.5V VDD5V: 3V
Magnetic Input Specification
Two-pole cylindrical diametrically magnetised source:
Parameter
Diameter Magnetic input field amplitude Magnetic offset Field non-linearity Input frequency (rotational speed of magnet) fmag_abs fmag_inc Btc Disp typ. - 0.035 0.25
Symbol
dmag Bpk Boff
Min
4 45
Max
Unit
mm
Note
Recommended diameter: 6mm Required vertical component of the magnetic field strength on the die's surface, measured along a concentric circle with a radius of 1.1mm Constant magnetic stray field Including offset gradient Absolute mode: 600 rpm @ readout of 1024 positions (see table 6) Incremental mode: no missing pulses at rotational speeds of up to 10,000 rpm (see table 6) Samarium Cobalt ReComa28 Max. offset between defined device center and magnet axis (see Figure 16)
75 5 5 10 166
mT mT % Hz Hz %/K mm
Magnetic field temperature drift Displacement radius
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AS5040 10-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER
Electrical System Specifications
Parameter
Resolution 7 bit 8 bit 9 bit 10 bit Integral non-linearity (optimum) INLopt
Symbol
RES
Min
Typ
2.813 1.406 0.703 0.352
Max
10
Unit
bit
Note
0.352 deg Adjustable resolution only available for incremental output modes; Least significant bit, minimum step Maximum error with respect to the best line fit. Verified at optimum magnet placement @ 25 C. Best line fit = (Errmax - Errmin) / 2 Over displacement tolerance and full operating temperature range with 6mm diameter magnet 10bit no missing codes RMS equivalent to 1 sigma 0.352 deg (1 LSB) hysteresis available upon request DC supply voltage 3.3V (VDD3V3) DC supply voltage 3.3V (VDD3V3) *...Until offset compensation finished Includes delay of ADC, DSP, absolute interface Calculation over two samples Internal sampling rate Max. clock frequency to read out serial data
deg
0.5
deg
Integral non-linearity Differential non-linearity Transition noise Hysteresis Power-on reset thresholds On Voltage; 300mV typ. Hysteresis Off Voltage; 300mV typ. Hysteresis Power-up time System propagation delay absolute output System propagation delay incremental output Sampling rate for absolute output Read-out frequency
INL DNL TN Hyst Von Voff tPwrUp tdelay 1,37 1.08 100 0.704 2.2 1.9
1.4 0.176 0.12
deg deg Deg RMS deg
2.9 2.6 400 * 65 200
V V ms s s kHz MHz
fS CLK
9.5
10
10.5 1
1023
10bit
1023 TN DNL actual curve ideal curve 0.35
2 1 0
512
512
0 0
INL
180
Figure 18:
360
Integral and differential Non-Linearity (example)
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 10-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER
Timing Characteristics
Synchronous Serial Interface (SSI)
Parameter
Data output activated (logic high) First data shifted to output register Start of data output Data output valid Data output tristate Pulse width of CSn Read-out frequency
Symbol
t DO active tCLK FE T CLK / 2 t DO valid t DO tristate t CSn fCLK
Min
Typ
Max
100
Unit
ns ns ns
Note
Time between falling edge of CSn and data output activated Time between falling edge of CSn and first falling edge of CLK 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
500 500 375 100 500 >0 1
ns ns ns MHz
Pulse Width Modulation Output
Parameter
PWM frequency Minimum pulse width Maximum pulse width
Symbol
f PWM PW MIN PW MAX
Min
0.927 0.95 973
Typ
0.976 1 1024
Max
1.024 1.05 1075
Unit
KHz s s
Note
Signal period = 1025 s 5% Position 0d; Angle 0 degree Position 1023d; Angle 359.65 degree
Incremental Outputs
Parameter
Incremental outputs valid after power-up Directional indication valid
Symbol
t Incremental
outputs valid
Min
Typ
Max
500 500
Unit
ns ns
Note
Time between first falling edge of CSn after power-up and valid incremental outputs Time between rising or falling edge of LSB output and valid directional indication
t Dir valid
Programming Conditions
Parameter
Programming enable time Write data start Write data valid Load Programming data Write data - programming CLK PROG CLK pulse width Hold time of Vprog after programming Programming voltage Programming current
Symbol
t Prog enable t Data in t Data in valid t Load PROG CLK PROG t PROG t PROG finished V PROG I PROG
Min
2 2 250 2
Typ
Max
Unit
s s ns s
Note
Time between rising edge at Prog pin and rising edge of CSn
Write data at the rising edge of CLK PROG
250 1.8 2 7.3 7.4 7.5 130 2 2.2
kHz s s V mA during programming; 16 clock cycles Programmed data is available after next power-on Must be switched off after zapping during programming
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AS5040 10-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER
Package Drawings and Markings
16-Lead Shrink Small Outline Package SSOP-16
AYWWIZZ AS5040
Symbol
Dimensions mm
min. typ. max min.
Marking: AYWWIZZ
inch
typ. max.
A:Pb-Free Identifier Y:Last Digit of Manufacturing Year WW: Manufacturing Week I: Plant Identifier ZZ: Traceability Code
A A1 A2 b c D E E1 e K L
1.73 0.05 1.68 0.25 0.09 6.07 7.65 5.2 0 0.63
1.86 0.13 1.73 0.315 6.20 7.8 5.3 0.65 0.75
1.99 0.21 1.78 0.38 0.20 6.33 7.9 5.38 8 0.95
.068 .002 .066 .010 .004 .239 .301 .205 0 .025
.073 .005 .068 .012 .244 .307 .209 .0256 .030
.078 .008 .070 .015 .008 .249 .311 .212 8 .037
JEDEC Package Outline Standard: MO - 150 AC Thermal Resistance Rth(j-a): 151 K/W IC's marked with a white dot or the letters "ES" denote Engineering Samples
Ordering Information
Delivery: Tape and Reel (1 reel = 2000 devices) Tubes (1 box = 100 tubes a 77 devices)
Order # 12817-002 for delivery in tubes Order # 12817-202 for delivery in tape and reel
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AS5040 10-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER
Recommended PCB footprint:
recommended footprint data A B C D E
mm 9.02 6.16 0.46 0.65 5.01 inch 0.355 0.242 0.018 0.025 0.197
Revision History
Revision
1.0
Date
April. 2, 2004 updated Fig.7
Description
added Fig.8 : Daisy Chain Mode combine Vzapp = Vprog add Fig.18: INL / DNL example DC characteristics: remove absolute schmitt trigger input thresholds Timing characteristics: add Fclk min change max. power-up time change programming characteristics: tLoad PROG, CLK PROG add package outlines and markings add definition of parity bit add description of high speed operation for absolute mode change tDOvalid
1.1
Jun. 11, 2004
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AS5040 10-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER
Contact Headquarters
austriamicrosystems AG A 8141 Schloss Premstatten, Austria Phone: Fax: +43 3136 500 0 +43 3136 525 01
industry.medical@austriamicrosystems.com www.austriamicrosystems.com
Sales Offices
austriamicrosystems Germany GmbH Tegernseer Landstrasse 85 D-81539 Munchen, Germany Phone: Fax: +49 89 69 36 43 0 +49 89 69 36 43 66 austriamicrosystems USA, Inc. 8601 Six Forks Road Suite 400 Raleigh, NC 27615, USA Phone: Fax: +1 919 676 5292 +1 509 696 2713
austriamicrosystems Italy S.r.l. Via A. Volta, 18 I-20094 Corsico (MI), Italy Phone: Fax: +39 02 4586 4364 +39 02 4585 773
austriamicrosystems USA, Inc. 4030 Moorpark Ave Suite 116 San Jose, CA 95117, USA Phone: Fax: +1 408 345 1790 +1 509 696 2713
austriamicrosystems France S.A.R.L. 124, Avenue de Paris F-94300 Vincennes, France Phone: Fax: +33 1 43 74 00 90 +33 1 43 74 20 98
austriamicrosystems AG Suite 811, Tsimshatsui Centre East Wing, 66 Mody Road Tsim Sha Tsui East, Kowloon, Hong Kong Phone: Fax: +852 2268 6899 +852 2268 6799
austriamicrosystems Switzerland AG Rietstrasse 4 CH 8640 Rapperswil, Switzerland Phone: Fax: +41 55 220 9008 +41 55 220 9001
austriamicrosystems AG AIOS Gotanda Annex 5 t h Fl., 1-7-11, Higashi-Gotanda, Shinagawa-ku Tokyo 141-0022, Japan Phone: Fax: +81 3 5792 4975 +81 3 5792 4976
austriamicrosystems UK, Ltd. 88, Barkham Ride, Finchampstead, Wokingham Berkshire RG40 4ET, United Kingdom Phone: Fax: +44 118 973 1797 +44 118 973 5117
austriamicrosystems AG #805, Dong Kyung Bldg., 824-19, Yeok Sam Dong, Kang Nam Gu, Seoul
Korea 135-080
austriamicrosystems AG Klaavuntie 9 G 55 FI 00910 Helsinki, Finland Phone: Fax: +358 9 72688 170 +358 9 72688 171
Phone: Fax:
+82 2 557 8776 +82 2 569 9823
austriamicrosystems AG Singapore Representative Office 83 Clemenceau Avenue, #02-01 UE Square 239920, Singapore Phone: Fax: +65 68 30 83 05 +65 62 34 31 20
austriamicrosystems AG Bivagen 3B S 19163 Sollentuna, Sweden Phone: +46 8 6231 710
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AS5040 10-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER
Copyright
Devices sold by austriamicrosystems are covered by the warranty and patent indemnification provisions appearing in its Term of Sale. austriamicrosystems 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 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 for current information. This product is intended for use in normal commercial applications. Copyright (c) 2004 austriamicrosystems. Trademarks registered (R). 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. To the best of its knowledge, austriamicrosystems asserts that the information contained in this publication is accurate and correct. However, austriamicrosystems 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 rendering of technical or other services.
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