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AS5045 PROGRAMMABLE MAGNETIC ROTARY ENCODER
Features
Contactless high resolution rotational position encoding over full turn degrees digital 12bit absolute outputs: Serial interface Pulse width modulated (PWM) output User programmable zero position Failure detection mode magnet placement monitoring loss power supply "red-yellow-green" indicators display placement magnet Z-axis Serial read-out multiple interconnected AS5045 devices using Daisy Chain mode Tolerant magnet misalignment airgap variations Wide temperature range: 40°C 125°C Small Pb-free package: SSOP (5.3mm 6.2mm)
AS5045 contactless magnetic rotary encoder accurate angular measurement over full turn 360°. system-on-chip, combining integrated Hall elements, analog front digital signal processing single device. measure angle, only simple two-pole magnet, rotating over center chip, required. magnet placed above below absolute angle measurement provides instant indication magnet's angular position with resolution 0.0879° 4096 positions revolution. This digital data available serial stream signal. internal voltage regulator allows AS5045 operate either supplies
Applications
Industrial applications: Contactless rotary position sensing Robotics Automotive applications: Steering wheel position sensing Transmission gearbox encoder Headlight position control Torque sensing Valve position sensing Replacement high potentiometers
Figure Typical arrangement AS5045 magnet
Benefits
Complete system-on-chip Flexible system solution provides absolute outputs simultaneously Ideal applications harsh environments contactless position sensing calibration required
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AS5045 12-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER
Configuration
MagINCn MagDECn Mode Prog_DI
VDD5V VDD3V3
Symbol
Type
DI_PU,
Description
Clock Input Synchronous Serial Interface; Schmitt-Trigger input Chip Select, active low; SchmittTrigger input, internal pull-up resistor (~50k) Pulse Width Modulation approx. 244Hz; 1µs/step (opt. 122Hz; 2µs/step) Must left unconnected Must left unconnected 3V-Regulator Output, internally regulated from VDD5V. Connect VDD5V supply voltage. load externally. Positive Supply Voltage,
AS5045
VDD3V3 VDD5V
Figure configuration SSOP16
Description
DO_OD DI_PD DI_PU digital digital digital digital
Table description SSOP16 output open drain output input pull-down input pull-up DO_T supply digital input digital output /tri-state Schmitt-Trigger input
Table shows description each standard SSOP16 package (Shrink Small Outline Package, leads, body size: 5.3mm 6.2mmm; Figure Pins supply pins, pins internal must connected. Pins MagINCn MagDECn magnetic field change indicators (magnetic field strength increase decrease through variation distance between magnet device). These outputs used detect valid magnetic field range. Furthermore those indicators also used contact-less pushbutton functionality. Mode allows switching between filtered (slow) unfiltered (fast mode). This must tied VDD5V, must switched after power section
Prog used program zero-position into (see chapter 8.1). This also used digital input shift serial data through device Daisy Chain configuration, (see page 11). Chip Select (CSn; active low) selects device within network AS5045 encoders initiates serial data transfer. logic high puts data output (DO) tri-state terminates serial data transfer. This also used alignment mode (Figure programming mode (Figure 10). allows single wire output 10-bit absolute position value. value encoded into pulse width modulated signal with pulse width step (1µs 4096µs over full turn). using external pass filter, digital signal converted into analog voltage, making direct replacement potentiometers possible.
Symbol
MagINCn
Type
DO_OD
Description
Magnet Field Magnitude INCrease; active low, indicates distance reduction between magnet device surface. Table Magnet Field Magnitude DECrease; active low, indicates distance increase between device magnet. Table Must left unconnected Must left unconnected Must left unconnected Select between slow (low, VSS) fast (high, VDD5V) mode. Internal pull-down resistor. Negative Supply Voltage (GND) Programming Input Data Input Daisy Chain mode. Internal pull-down resistor (~74k). Connect used Data Output Synchronous Serial Interface
MagDECn Mode Prog_DI
DO_OD DI_PD
DO_T
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AS5045 12-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER
Electrical Characteristics
AS5045 Differences AS5040
AS5045 12bits, 0.088°/step. read: 18bits (12bits data bits status) write: bits (12bits zero position bits mode selection) used used 4:not used MagINCn, MagDECn: same feature AS5040, additional option red-yellow-green magnetic range MODE pin, switch between fast slow mode output: frequency selectable OTP: step, 4096 steps revolution, f=244Hz 2µs/ step, 4096 steps revolution, f=122Hz selectable MODE input pin: 2.5kHz, 10kHz 384µs (slow mode) 96µs (fast mode) 0.03 degrees max. (slow mode) 0.06 degrees max. (fast mode) zero position, rotational direction, disable, Magnetic Field indicator modes, frequencies AS5040 10bit, 0.35°/step read: 16bits (10bits data bits status) write: bits (10bits zero position bits mode selection) quadrature, step/direction BLDC motor commutation modes 3:incremental output A_LSB_U 4:incremental output B_DIR_V MagINCn, MagDECn indicate in-range out-of-range magnetic field plus movement magnet z-axis 6:Index output output: step, 1024 steps revolution, 976Hz frequency fixed 10kHz @10bit resolution 48µs 0.12 degrees zero position, rotational direction, incremental modes, index width
parameters according AS5040 datasheet except parameters shown below: Building Block Resolution Data length
incremental encoder
Pins
sampling frequency Propagation delay Transition noise (rms; 1sigma) programming options
Absolute Maximum Ratings (non operating)
Stresses beyond those listed under "Absolute Maximum Ratings" cause permanent damage device. These stress ratings only. Functional operation device these other conditions beyond those indicated under "Operating Conditions" implied. Exposure absolute maximum rating conditions extended periods affect device reliability.
Parameter supply voltage VDD5V supply voltage VDD3V3 Input voltage Input current (latchup immunity) Electrostatic discharge Storage temperature Body temperature (Lead-free package) Humidity non-condensing
Revision
Symbol VDD5V VDD3V3 Iscr Tstrg TBody
-0.3
Unit
Note
-0.3 -100
VDD5V +0.3
Except VDD3V3 Norm: JEDEC Norm: method 3015 67°F +257°F t=20 40s, Norm: IPC/JEDEC J-Std-020C Lead finish 100% "matte tin"
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AS5045 12-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER
Operating Conditions
Symbol Tamb Isupp VDD5V VDD3V3 VDD5V VDD3V3 Unit Operation 3.3V Operation (pin VDD5V VDD3V3 connected) Note -40°F.+257°F
Parameter Ambient temperature Supply current Supply voltage VDD5V Voltage regulator output voltage VDD3V3 Supply voltage VDD5V Supply voltage VDD3V3
3.4.
Characteristics Digital Inputs Outputs
CMOS Schmitt-Trigger Inputs: CLK, CSn. (CSn internal Pull-up)
(operating conditions: +125°C, VDD5V 3.0-3.6V operation) VDD5V 4.5-5.5V operation) unless otherwise noted)
Parameter High level input voltage level input voltage Schmitt Trigger hysteresis Input leakage current Pull-up level input current
Symbol VIon- VIoff ILEAK
VDD5V
VDD5V
Unit
Note Normal operation
-100
only only, VDD5V: 5.0V
3.4.2
CMOS Program Input: Prog
(operating conditions: +125°C, VDD5V 3.0-3.6V operation) VDD5V 4.5-5.5V operation) unless otherwise noted)
Parameter High level input voltage High level input voltage level input voltage High level input current
Symbol VPROG
VDD5V
VDD5V
Unit
Note
"programming conditions" VDD5V
During programming
VDD5V: 5.5V
3.4.3
CMOS Output Open Drain: MagINCn, MagDECn
(operating conditions: +125°C, VDD5V 3.0-3.6V operation) VDD5V 4.5-5.5V operation) unless otherwise noted)
Parameter level output voltage Output current Open drain leakage current
Symbol
VSS+0.4
Unit
Note VDD5V: 4.5V VDD5V:
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AS5045 12-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER
3.4.4
CMOS Output:
(operating conditions: +125°C, VDD5V 3.0-3.6V operation) VDD5V 4.5-5.5V operation) unless otherwise noted)
Parameter High level output voltage level output voltage Output current
Symbol
VDD5V-0.5
VSS+0.4
Unit
Note
VDD5V: 4.5V VDD5V:
3.4.5
Tristate CMOS Output:
(operating conditions: +125°C, VDD5V 3.0-3.6V operation) VDD5V 4.5-5.5V operation) unless otherwise noted)
Parameter High level output voltage level output voltage Output current Tri-state leakage current
Symbol
VDD5V -0.5
VSS+0.4
Unit
Note
VDD5V: 4.5V VDD5V:
Magnetic Input Specification
(operating conditions: +125°C, VDD5V 3.0-3.6V operation) VDD5V 4.5-5.5V operation) unless otherwise noted)
Two-pole cylindrical diametrically magnetised source: Parameter Diameter Thickness Magnetic input field amplitude Magnetic offset Field non-linearity Input frequency (rotational speed magnet) Displacement radius Eccentricity Recommended magnet material temperature drift fmag_abs Symbol dmag tmag Boff 2.44 0.61 Disp
-0.12 -0.035
Unit
Note Recommended magnet: 2.5mm cylindrical magnets Required vertical component magnetic field strength die's surface, measured along concentric circle with radius 1.1mm Constant magnetic stray field Including offset gradient 4096 positions/rev.; fast mode 36.6rpm 4096 positions/rev.; slow mode
0.25
Max. offset between defined device center magnet axis (see Figure Eccentricity magnet center rotational axis NdFeB (Neodymium Iron Boron) SmCo (Samarium Cobalt)
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AS5045 12-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER
Electrical System Specifications
Symbol INLopt INLtemp Unit Note 0.088 Maximum error with respect best line fit. Centered magnet without calibration, Tamb Maximum error with respect best line fit. Centered magnet without calibration, Tamb +125°C Best line (Errmax Errmin) Over displacement tolerance with diameter magnet, without calibration, Tamb +125°C 12bit, missing codes sigma, fast mode (MODE sigma, slow mode (MODE=0 open) supply voltage 3.3V (VDD3V3) supply voltage 3.3V (VDD3V3) Fast mode (Mode Until status Slow mode (Mode open); Until Fast mode (MODE=1) Slow mode (MODE=0 open) Tamb 25°C, slow mode (MODE=0 open) Tamb +125°C, slow mode (MODE=0 open) Tamb 25°C, fast mode (MODE Tamb +125°C, fast mode (MODE Max. clock frequency read serial data
(operating conditions: +125°C, VDD5V 3.0~3.6V operation) VDD5V 4.5~5.5V operation) unless otherwise noted)
Parameter Resolution Integral non-linearity (optimum) Integral non-linearity (optimum)
Integral non-linearity Differential non-linearity Transition noise Power-on reset thresholds
voltage; 300mV typ. hysteresis voltage; 300mV typ. hysteresis
Voff tPwrUp 1.37 1.08
±0.044 0.06 0.03 2.48 2.61 2.61 10.42 10.42 2.74 2.87 10.94 11.46
Power-up time System propagation delay absolute output delay ADC, absolute interface Internal sampling rate absolute output: Internal sampling rate absolute output Read-out frequency
tdelay
2.35 9.90 9.38
4095
12bit code
4095
Actual curve DNL+1LSB 0.09° Ideal curve
2048
2048
180°
Figure Integral differential non-linearity (example)
[degrees]
Integral Non-Linearity (INL) maximum deviation between actual position indicated position. Differential Non-Linearity (DNL) maximum deviation step length from position next. Transition Noise (TN) repeatability indicated position
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AS5045 12-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER
3.7.
Timing Characteristics
Synchronous Serial Interface (SSI)
(operating conditions: +125°C, VDD5V 3.0~3.6V operation) VDD5V 4.5~5.5V operation) unless otherwise noted)
Parameter Data output activated (logic high) First data shifted output register Start data output Data output valid Data output tristate Pulse width Read-out frequency 3.7.2
Symbol active tCLK valid tristate fCLK
Unit
Note Time between falling edge data output activated Time between falling edge first falling edge Rising edge shifts time Time between rising edge data output valid After last changes back "tristate" high; initiate read-out next angular position Clock frequency read serial data
Pulse Width Modulation Output
(operating conditions: +125°C, VDD5V 3.0~3.6V operation) VDD5V 4.5~5.5V operation) unless otherwise noted)
Parameter frequency Minimum pulse width
Symbol
0.95
1.05
Unit
Note Signal period 4097µs Tamb 25°C 4097µs ±10% Tamb +125°C Position Angle
Maximum pulse width 3891 4096 4301 Position 4095d; Angle 359.91° Note: when "PWMhalfEn" set, pulse width doubled (PWM frequency divided
Programming Conditions
Symbol Prog enable Data Data valid Load PROG PrgR PrgH PROG PROG PROG finished PROG ProgOff PROG
CLKAread
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(operating conditions: +125°C, VDD5V 3.0~3.6V operation) VDD5V 4.5~5.5V operation) unless otherwise noted)
Parameter Programming enable time Write data start Write data valid Load Programming data Rise time VPROG before CLKPROG Hold time VPROG after PROG Write data programming PROG pulse width Hold time Vprog after programming Programming voltage, PROG Programming voltage level Programming current
Analog Read
Revision
Unit
Note Time between rising edge Prog rising edge Write data rising edge PROG
ensure that VPROG stable with rising edge during programming; clock cycles Programmed data available after next power-on Must switched after zapping Line must discharged this level during programming Analog Readback mode
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AS5045 12-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER
Parameter
Programmed Zener Voltage (log.1) Unprogrammed Zener Voltage (log.
Symbol
Vprogrammed Vunprogrammed
Unit
Note VRef-VPROG during Analog Readback mode (see 8.4)
Functional Description
AS5045 manufactured CMOS standard process uses spinning current Hall technology sensing magnetic field distribution across surface chip. integrated Hall elements placed around center device deliver voltage representation magnetic field surface Through Sigma-Delta Analog Digital Conversion Digital Signal-Processing (DSP) algorithms, AS5045 provides accurate high-resolution absolute angular position information. this purpose Coordinate Rotation Digital Computer (CORDIC) calculates angle magnitude Hall array signals. also used provide digital information outputs that indicate movements used magnet towards away from device's surface.
small cost diametrically magnetized (two-pole) standard magnet provides angular position information (see Figure 17). AS5045 senses orientation magnetic field calculates 12-bit binary code. This code accessed Synchronous Serial Interface (SSI). addition, absolute angular representation given Pulse Width Modulated signal (PWM). This signal output also allows generation direct proportional analogue voltage, using external LowPass-Filter. AS5045 tolerant magnet misalignment magnetic stray fields differential measurement technique Hall sensor conditioning circuitry.
Figure AS5045 block diagram
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AS5045 12-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER
Mode Input
mode input activates deactivates internal filter that used reduce analog output noise. Activating filter (Mode LOW) provides reduced output noise 0.03° rms. same time, output delay increased 384µs. This mode recommended high precision, speed applications. Deactivating filter (Mode HIGH) reduces output delay 96µs provides output noise 0.06° rms. This mode recommended higher speed applications. MODE should power-up. change mode during operation allowed. Switching Mode affects following parameters: Parameter sampling rate transition noise sigma) output delay max. speed 4096 samples/rev. max. speed 1024 samples/rev. max. speed samples/rev. max. speed samples/rev. slow mode (Mode low) 2.61 (384 0.03° 384µs 2441 fast mode (Mode high, VDD5V) 10.42 (96µs) 0.06° 96µs 2441 9766
Table Slow fast mode parameters 12-bit Absolute Angular Position Output
5.CSn
Synchronous Serial Interface (SSI)
tCLK TCLK/2
tCLK
tCSn
Even
active
valid Angular Position Data Status Bits
Tristate
Figure Synchronous serial interface with absolute angular position data
changes logic low, Data (DO) will change from high impedance (tri-state) logic high read-out will initiated. After minimum time data latched into output shift register with first falling edge CLK. Each subsequent rising edge shifts data. serial word contains bits, first bits angular information D[11:0], subsequent bits contain system information, about validity data such OCF, COF, LIN, Parity Magnetic Field status (increase/decrease). subsequent measurement initiated "high" pulse with minimum duration CSn.
5.1.
Data Content
D11:D0 absolute angular position data (MSB clocked first) (Offset Compensation Finished), logic high indicates finished Offset Compensation Algorithm (Cordic Overflow), logic high indicates range error CORDIC part. When this set, data D9:D0 invalid. absolute output maintains last valid angular value. This alarm resolved bringing magnet within X-Y-Z tolerance limits. (Linearity Alarm), logic high indicates that input field generates critical output linearity. When this set, data D9:D0 still used, contain invalid data. This warning resolved bringing magnet within X-Y-Z tolerance limits. Even Parity transmission error detection bits 1.17 (D11.D0, OCF, COF, LIN, MagINC, MagDEC)
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AS5045 12-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER
Placing magnet above chip, angular values increase clockwise direction default. Data D11:D0 valid, when status bits have following configurations: even checksum bits 1:15 Parity
Table Status outputs
MagInc=MagDec=1 only recommended YELLOW mode (see Table
5.1.2
Z-axis Range Indication (Push Button Feature, Red/Yellow/Green Indicator) serial data stream (see Figure Additionally, programming option available with MagCompEn (see Figure that enables additional features:
AS5045 provides several options detecting movement distance magnet Z-direction. Signal indicators MagINCn MagDECn available both hardware pins (pins status bits default state, status bits MagINC, MagDec pins MagINCn, MagDECn have following function: Status bits Hardware pins INCn DECn
OTP: CompEn (default) Description distance change Magnetic input field range, ~45.75mT) Distance increase; pull-function. This state dynamic only active while magnet moving away from chip. Distance decrease; push- function. This state dynamic only active while magnet moving towards chip. Magnetic field ~<45mT >~75mT. still possible operate AS5045 this range, recommended
Table Magnetic field strength variation indicator
When MagCompEn programmed OTP, function status bits MagINC, MagDec pins MagINCn, MagDECn changed following function: Status bits Hardware pins INCn DECn OTP: CompEn (red-yellow-green programming option) Description distance change Magnetic input field GREEN range, ~45.75mT) YELLOW range: magnetic field 25.45mT ~75.135mT. AS5045 still operated this range, with slightly reduced accuracy. range: magnetic field ~<25mT >~135mT. still possible operate AS5045 range, recommended. available
other combinations
Table Magnetic field strength red-yellow-green indicator (OTP option)
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AS5045 12-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER
Note: (MagINCn) (MagDECn) active open drain output require external pull-up resistor. magnetic field range, both outputs turned off. pins also combined with single pull-up resistor. this case, signal high when magnetic field range. other cases (see Table Table
Daisy Chain Mode
Daisy Chain mode allows connection several AS5045's series, while still keeping just digital input data transfer (see "Data Figure below). This mode accomplished connecting data output (DO; data input (PROG; subsequent device. filter must implemented between each PROG device device n+1, prevent then encoders enter alignment mode, case discharge, long cables, conform signal levels shape. Using values R=100R C=1nF allow max. frequency 1MHz whole chain. serial data connected devices read from first device chain. length serial stream increases with every connected device, (18+1) bits: e.g. devices, three devices, etc. last data first device (Parity) followed dummy first data second device (D11), etc. (see Figure
Figure Daisy Chain hardware configuration
tCLK TCLK/2
Even
active
valid Angular Position Data Device Status Bits Angular Position Data Device
Figure Daisy Chain mode data transfer
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AS5045 12-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER
Pulse Width Modulation (PWM) Output
When PWMhalfEN timing shown Table Parameter frequency pulse width pulse width Symbol fPWM PWMIN PWMAX 8192 Unit Note Signal period: 8194µs Position Angle Position 4095d Angle 359.91
AS5045 provides pulse width modulated output (PWM), whose duty cycle proportional measured angle:
Position
4097 (ton toff
frequency internally trimmed accuracy (±10% over full temperature range). This tolerance cancelled measuring complete duty cycle shown above.
Table signal parameters with half frequency (OTP option)
Analog Output
Angle (Pos
analog output generated averaging signal, using external active passive lowpass filter. analog output voltage proportional angle: 360° VDD5V.
4097µs
359.91 (Pos 4095)
4096µs
Using this method, AS5045 used direct replacement potentiometers. Pin12 Pin7 analog
1/fPWM
Figure output signal
360°
Changing Frequency
Figure Simple order passive lowpass filter
frequency AS5045 divided setting (PWMhalfEN) register (see chapter With PWMhalfEN timing shown Table Parameter frequency pulse width pulse width Symbol fPWM PWMIN PWMAX 4096 Unit Note Signal period: 4097µs Position Angle Position 4095d Angle 359.91
Figure shows example simple passive lowpass filter generate analog output.
should avoid loading output. Larger values will provide better filtering less ripple, will also slow down response time.
Table signal parameters (default mode)
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AS5045 12-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER
Programming AS5045
Zero Position Programming
After power-on, programming AS5045 enabled with rising edge Prog logic high. configuration data must serially shifted into register Prog pin. first "CCW" followed zero position data (MSB first) Mode setting bits. Data must valid rising edge (see Figure 10). After writing data into register permanently programmed rising Prog programming voltage PROG pulses PROG must applied program fuses (Figure 11). exit programming mode, chip must reset poweron-reset. programmed data available after next power-up. Note: During programming process, transitions programming current cause high voltage spikes generated inductance connection cable. avoid these spikes possible damage connection wires, especially signals Prog must kept short possible. maximum wire length between PROG switching transistor Prog should exceed 50mm inches). suppress eventual voltage spikes, 10nF ceramic capacitor should connected close pins VPROG VSS. This capacitor only required programming, required normal operation. clock timing must selected proper rate ensure that signal Prog stable rising edge (see Figure 10). Additionally, programming supply voltage should buffered with 10µF capacitor mounted close switching transistor. This capacitor aids providing peak currents during programming. specified programming voltage Prog 7.5V (see section 3.8). compensate voltage drop across PROG switching transistor, applied programming voltage slightly higher (7.5 8.0V, Figure 12). Register Contents: Counter Clockwise ccw=0 angular value increases clockwise direction ccw=1 angular value increases counterclockwise direction [11:0]: dis: MagCompEn: Programmable Zero Position Disable output when set, activates alarm both when magnetic field high (see Table when set, frequency 122Hz step (when PWMhalfEN frequency 244Hz, step)
Zero position programming option that simplifies assembly system, magnet does need manually adjusted mechanical zero position. Once assembly completed, mechanical electrical zero positions matched software. position within full turn defined permanent zero position. zero position programming, magnet turned mechanical zero position (e.g. "off"-position rotary switch) actual angular value read. This value written into register bits Z11:Z0 (see Figure programmed described section
Note: zero position value also modified before programming, e.g. program electrical zero position that 180° (half turn) from mechanical zero position, just 2048 value read mechanical zero position program value into register.
Repeated Programming
Although single AS5045 register programmed only once (from possible program other, unprogrammed bits subsequent programming cycles. However, that already been programmed should programmed twice. Therefore recommended that bits that already programmed during programming cycle.
Non-permanent Programming
also possible re-configure AS5045 nonpermanent overwriting register. This procedure essentially "Write Data" sequence (see Figure without subsequent programming cycle. "Write Data" sequence applied time during normal operation. This configuration remains while power supply voltage above power-on reset level (see 3.6). Application Note AN5000-20 further information.
PWMhalfEn:
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AS5045 12-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER
atain
half
PROG
enab
atain
ositio
status
Figure Programming access write data (section Figure
Write Data
Programming Mode
Power
Prog CLKPROG
Data
7.5V VProgOff
tLoad PROG
tPrgH tPrgR tPROG
Figure Complete programming sequence
tPROG finished
AS5045 Demoboard
programming, keep these wires short possible! max. length inches (5cm)
MagINCn
VDD5V VDD3V3
MagDECn
*see Text PROG 5VUSB VDD3V3
Mode
Prog_DI
AS5045
only required programming
Figure programming connection AS5045 (shown with AS5045 demoboard)
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connect interface VPROG 10µF 8.0V only required programming
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AS5045 12-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER
Analog Readback Mode
following falling slope changes PROG analog output, providing reference voltage that must saved reference calculation subsequent programmed unprogrammed bits. Following this step, each rising slope outputs data reverse order during programming (see Figure Md0-MD1-Div0,Div1-Indx-Z0.Z11, ccw). capacitor connected PROG, should removed during analog readback mode allow fast readout rate. capacitor removed analog voltage will take longer stabilize additional capacitance. measured analog voltage each must subtracted from previously measured resulting value gives indication quality programmed bit: reading <100mV indicates properly programmed reading indicates properly unprogrammed bit. reading between 100mV indicates faulty bit, which result undefined digital value, when read power-up. Following clock (after reading "ccw"), chip must reset disconnecting power supply.
Non-volatile programming (OTP) uses on-chip zener diodes, which become permanently resistive when subjected specified reverse current. quality programming process depends amount current that applied during programming process 130mA). This current must provided external voltage source. this voltage source cannot provide adequate power, zener diodes programmed properly. order verify quality programmed bit, analog level read each zener diode, giving indication whether this particular properly programmed not. AS5045 Analog Readback Mode, digital sequence must applied pins CSn, PROG shown Figure digital level this depends supply configuration (3.3V section second rising edge (OutpEN) changes PROG digital output log. high signal PROG must removed avoid collision outputs (grey area Figure 13).
ProgEN
OutpEN
Analog Readback Data PROG
Vref Vprogrammed
Internal test digital
Power-onReset; turn supply
PROG
halfEN Comp Prog changes Output
Vunprogrammed
tLoadProg
CLKAread
Figure register analog read
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AS5045 12-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER
Alignment Mode
alignment mode simplifies centering magnet over center chip gain maximum accuracy. Alignment mode enabled with falling edge while Prog logic high (Figure 14). Data bits D9-D0 change 12-bit displacement amplitude output. high value indicates large displacement, also higher absolute magnetic field strength. magnet properly aligned, when difference between highest lowest value over full turn minimum. Under normal conditions, properly aligned magnet will result reading less than over full turn. MagINCn MagDECn indicators will when alignment mode reading 128. same time, both hardware pins MagINCn (#1) MagDECn (#2) will pulled VSS. properly aligned magnet will therefore produce MagINCn MagDECn signal throughout full 360° turn magnet. Stronger magnets short gaps between magnet show values larger than 128. These magnets still properly aligned long difference between highest lowest value over full turn minimum. alignment mode reset normal operation power-on-reset (disconnect re-connect power supply) falling edge with Prog low.
Prog
AlignMode enable
3.3V operation, must bypassed connecting VDD3V3 with VDD5V (see Figure 16:). operation, supply connected VDD5V, while VDD3V3 (LDO output) must buffered 2.2.10µF capacitor, which supposed placed close supply (see Figure 16:). VDD3V3 output intended internal only must loaded with external load. output voltage digital interface I/O's corresponds voltage VDD5V, buffers supplied from this (see Figure 16:).
Operation
2.2.10µF
VDD3V3
100n
VDD5V
Internal
5.5V
Prog
3.3V Operation
Read-out
VDD5V VDD3V3
100n
Internal
min. min.
Figure Enabling alignment mode
3.6V
Prog
exit AlignMode
Read-out
Prog
Figure Exiting alignment mode Figure Connections 3.3V supply voltages
3.3V Operation
AS5045 operates either 3.3V ±10% ±10%. This made possible internal 3.3V LowDropout (LDO) Voltage regulator. internal supply voltage always taken from output LDO, meaning that internal blocks always operating 3.3V.
Revision
buffer capacitor 100nF recommended both cases close VDD5V. Note that VDD3V3 must always buffered capacitor. must left floating, this cause instable internal 3.3V supply voltage which lead larger than normal jitter measured angle.
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AS5045 12-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER
Choosing Proper Magnet
Typically magnet should diameter 2.5mm height. Magnetic materials such rare earth AlNiCo/SmCo5 NdFeB recommended.
Physical Placement Magnet
best linearity achieved placing center magnet exactly over defined center chip shown drawing below:
magnetic field strength perpendicular surface range ±45mT.±75mT (peak).
magnet's field strength should verified using gauss-meter. magnetic field given distance, along concentric circle with radius 1.1mm (R1), should range ±45mT.±75mT. (see Figure 17).
typ. diameter
2.433 Defined center
2.433 Area recommended maximum magnet misalignment
Magnet axis
Figure Defined chip center magnet displacement radius
Magnet axis
Magnet Placement magnet's center axis should aligned within displacement radius 0.25mm from defined center magnet placed below above device. distance should chosen such that magnetic field surface within specified limits (see Figure 17). typical distance between magnet package surface 0.5mm 1.5mm, provided recommended magnet material dimensions (6mm 3mm). Larger distances possible, long required magnetic field strength stays within defined limits. However, magnetic field outside specified range still produce usable results, out-of-range condition will indicated MagINCn (pin MagDECn (pin Table
Vertical field component
concentric circle; radius 1.1mm Vertical field component (45.75mT)
Figure Typical magnet (6x3mm) magnetic field distribution
surface
Package surface
0.576mm 0.1mm 1.282mm 0.15mm
Figure Vertical placement magnet
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AS5045 12-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER
Simulation Modeling
±0.235mm
differential sampling sine cosine vectors removes common mode error components introduced magnetic source itself external disturbing magnetic fields. ratiometric division sine cosine vectors removes need accurate absolute magnitude magnetic field thus accurate Z-axis alignment magnetic source.
2.433 ±0.235mm
recommended differential input range magnetic field strength (X1-X2) (Y1-Y2) ±75mT surface die. addition this range, additional offset ±5mT, caused unwanted external stray fields allowed.
AS5045
Center
Radius circular Hall sensor array: 1.1mm radius
Figure Arrangement Hall sensor array chip (principle)
chip will continue operate, with degraded output linearity, signal field strength outside recommended range. strong magnetic fields will introduce errors saturation effects internal preamplifiers. weak magnetic fields will introduce errors noise becoming more dominant.
Failure Diagnostics
With reference Figure diametrically magnetized permanent magnet placed above below surface AS5045. chip uses array Hall sensors sample vertical vector magnetic field distributed across device package surface. area magnetic sensitivity circular locus 1.1mm radius with respect center die. Hall sensors area magnetic sensitivity grouped configured such that orthogonally related components magnetic fields sampled differentially. differential signal Y1-Y2 will give sine vector magnetic field. differential signal X1-X2 will give orthogonally related cosine vector magnetic field. angular displacement magnetic source with reference Hall sensor array then modelled AS5045 also offers several diagnostic failure detection features:
Magnetic Field Strength Diagnosis
software: MagINC MagDEC status bits will both high when magnetic field range. hardware: Pins (MagINCn) (MagDECn) open-drain outputs will both turned with external pull-up resistor) when magnetic field range. only outputs low, magnet either moving towards chip (MagINCn) away from chip (MagDECn).
13.2
Power Supply Failure Detection
arctan
0.5°
software: power supply AS5045 interrupted, digital data read will "0"s. Data only valid, when high, hence data stream with "0"s invalid. ensure adequate levels failure case, pull-down resistor (~10k) should added between receiving side hardware: MagINCn MagDECn pins open drain outputs require external pull-up resistors. normal operation, these pins high ohmic outputs high (see Table failure case, either when magnetic field range power supply missing, these outputs will become low. ensure adequate levels case broken power supply AS5045, pull-up resistors (~10k) from
±0.5° angular error assumes magnet optimally aligned over center result gain mismatch errors AS5045. Placement tolerances within package ±0.235mm direction, using reference point edge (see Figure order neglect influence external disturbing magnetic fields, robust differential sampling ratiometric calculation algorithm been implemented.
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AS5045 12-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER
each must connected positive supply (VDD5V). hardware: output: output constant stream pulses with 1kHz repetition frequency. case power loss, these pulses missing
Linearity Error over XY-misalignment
Angular Output Tolerances
14.1 Accuracy
1000 -200 -400 -600 -200 -800 -400 -600 -1000 -800 -1000 1000
Accuracy defined error between measured angle actual angle. influenced several factors: non-linearity analog-digital converters, internal gain mismatch errors, non-linearity misalignment magnet these errors, accuracy with centered magnet (Err specified better than ±0.5 degrees 25°C (see Figure 22). Misalignment magnet further reduces accuracy. Figure shows example 3D-graph displaying non-linearity over XY-misalignment. center square XY-area corresponds centered magnet (see center graph). axis extends misalignment ±1mm both directions. total misalignment area graph covers square (79x79mil) with step size 100µm. each misalignment step, measurement shown Figure repeated accuracy (Err (e.g. 0.25° Figure entered Z-axis 3D-graph.
Figure Example linearity error over misalignment
maximum non-linearity error this example better than degree (inner circle) over misalignment radius ~0.7mm. volume production, placement tolerance within package (±0.235mm) must also taken into account. total nonlinearity error over process tolerances, temperature misalignment circle radius 0.25mm specified better than ±1.4 degrees. magnet used this measurement cylindrical NdFeB (Bomatec® BMN-35H) magnet with diameter 2.5mm height.
Linearity error with centered magnet [degrees] -0.1 -0.2 -0.3 -0.4 -0.5
transition noise
Figure Example linearity error over 360°
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AS5045 12-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER
14.2
Transition Noise
nslow fast
Transition noise defined jitter transition between steps. nature measurement principle (Hall sensors Preamplifier ADC), there always certain degree noise involved. This transition noise voltage results angular transition noise outputs. specified 0.06 degrees sigma) fast mode (pin MODE high) 0.03 degrees sigma) slow mode (pin MODE open).
upper speed limit slow mode ~6.000rpm ~30.000rpm fast mode. only restriction high speed that there will fewer samples revolution speed increases (see Table Regardless rotational speed, absolute angular value always sampled highest resolution bit.
This repeatability indicated angle given mechanical position. transition noise different implications type output that used: Absolute output; interface: transition noise absolute output reduced user implementing averaging readings. averaging readings will reduce transition noise 50%, e.g. from 0.03°rms 0.015°rms sigma) slow mode. interface: interface used analog output adding pass filter, transition noise reduced lowering cutoff frequency filter. interface used digital interface with counter receiving side, transition noise again reduced averaging readings.
14.4
Propagation Delays
propagation delay delay between time that sample taken until converted available angular data. This delay 96µs fast mode 384µs slow mode. Using interface absolute data transmission, additional delay must considered, caused asynchronous sampling sample time takes external control unit read process angular data from chip (maximum clock rate 1MHz, number bits reading 18). 14.4.1 Angular Error Caused Propagation Delay
rotating magnet will cause angular error caused output propagation delay. This error increases linearly with speed: sampling prop.delay where sampling angular error rotating speed [rpm] prop.delay propagation delay [seconds] Note: since propagation delay known, automatically compensated control unit processing data from AS5045.
statistically, sigma represents 68.27% readings, sigma represents 99.73% readings.
14.3
14.3.
High Speed Operation
Sampling Rate
AS5045 samples angular value rate 2.61k (slow mode) 10.42k (fast mode, selectable MODE) samples second. Consequently, absolute outputs updated each 384µs (96µs fast mode). stationary position magnet, sampling rate creates additional error.
Absolute Mode sampling rate 2.6kHz/10.4kHz, number samples turn magnet rotating high speed calculated
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AS5045 12-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER
14.5
Internal Timing Tolerance
14.6
14.6.
Temperature
Magnetic Temperature Coefficient
AS5045 does require external ceramic resonator quartz. internal clock timings AS5045 generated on-chip oscillator. This oscillator factory trimmed accuracy room temperature (±10% over full temperature range). This tolerance influences sampling rate pulse width output:
Absolute output; interface: angular value updated every 400µs (typ.) output: angular value updated every 400µs (typ.). pulse timings also have same tolerance internal oscillator (see above). only pulse width used measure angle, resulting value also this timing tolerance. However, this tolerance cancelled measuring both calculating angle from duty cycle (see section
major benefits AS5045 compared linear Hall sensors that much less sensitive temperature. While linear Hall sensors require compensation magnet's temperature coefficients, AS5045 automatically compensates varying magnetic field strength over temperature. magnet's temperature drift does need considered, AS5045 operates with magnetic field strengths from ±45.±75mT.
Example: NdFeB magnet field strength 75mT -40°C temperature coefficient -0.12% Kelvin. temperature change from -40° +125° 165K. magnetic field change -0.12% -19.8%, which corresponds 75mT -40°C 60mT 125°C. AS5045 compensate this temperature related field strength change automatically, user adjustment required.
Position
4097 (ton toff
14.7
Accuracy over Temperature
influence temperature absolute accuracy very low. While accuracy ±0.5° room temperature, increase ±0.9° increasing noise high temperatures. 14.7.1 Timing Tolerance over Temperature
internal oscillator factory trimmed ±5%. Over temperature, this tolerance increase ±10%. Generally, timing tolerance influence accuracy resolution system, used mainly internal clock generation. only concern user width output pulse, which relates directly timing tolerance internal oscillator. This influence however cancelled measuring complete duty cycle instead just pulse (see 14.5).
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Package Drawings Markings
16-Lead Shrink Small Outline Package SSOP-16
AYWWIZZ AS5045
Dimensions
Symbol 0.55 0.05 1.65 0.22 0.09 5.90 7.40 5.00 1.75 6.20 7.80 5.30 0.65 0.75 0.95 .022 2.00 1.85 0.38 0.25 6.50 8.20 5.60 .002 .065 .009 .004 .232 .291 .197 .244 .307 .209 .0256 .030 .037 .069 .073 .015 .010 .256 .323 .220 inch .079
Marking: AYWWIZZ Pb-Free Identifier Last Digit Manufacturing Year Manufacturing Week Plant Identifier Traceability Code
JEDEC Package Outline Standard: Thermal Resistance th(j-a) typ. still air, soldered IC's marked with white letters "ES" denote Engineering Samples
Ordering Information
Delivery: Tape Reel reel 2000 devices) Tubes tubes devices)
Order AS5045ASSU Order AS5045ASST
delivery tubes delivery tape reel
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AS5045 12-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER
Recommended Footprint:
Recommended Footprint Data 9.02 6.16 0.46 0.65 5.01 inch 0.355 0.242 0.018 0.025 0.197
Contact
18.1 Headquarters
austriamicrosystems 8141 Schloss Austria Phone: Fax: 3136 3136
www.austriamicrosystems.com
Copyrights
Copyright 1997-2008, austriamicrosystems Schloss Premstaetten, 8141 Unterpremstaetten, Austria-Europe. Trademarks Registered rights reserved. material herein reproduced, adapted, merged, translated, stored, used without prior written consent copyright owner. products companies mentioned trademarks registered trademarks their respective companies. This product protected U.S. Patent 7,095,228.
Disclaimer
Devices sold austriamicrosystems covered warranty patent indemnification provisions appearing Term Sale. austriamicrosystems makes warranty, express, statutory, implied, description regarding information forth herein regarding freedom described devices from patent infringement. austriamicrosystems reserves right change specifications prices time without notice. Therefore, prior designing this product into system, necessary check with austriamicrosystems current information. This product intended normal commercial applications. Applications requiring extended temperature range, unusual environmental requirements, high reliability applications, such military, medical life-support lifesustaining equipment specifically recommended without additional processing austriamicrosystems each application. information furnished here austriamicrosystems believed correct accurate. However, austriamicrosystems shall liable recipient third party damages, including limited personal injury, property damage, loss profits, loss use, interruption business indirect, special, incidental consequential damages, kind, connection with arising furnishing, performance technical data herein. obligation liability recipient third party shall arise flow austriamicrosystems rendering technical other services.
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