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AS5145H/as5145a/as5145b 12-bit programmable magn etic rotary encoder www.ams.com/as5145 revision 1.17 1 - 36 1 general description the as5145 is a contact less magnetic rotary encoder for accurate angular measurement over a full turn of 360 degrees. it is a system-on-chip, combining integrated hall elements, analog front end and d igital 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 can be placed above or below the ic. the absolute angle measurement provides instant indication of the magnet?s angular position with a resolution of 0.0879o = 4096 positions per revolution. this digital data is available as a serial bit stream and as a pwm signal. an internal voltage regulator allows the as5145 to operate at either 3.3v or 5v supplies. 2 key features ?? contact less high resolution rotational position encoding over a full turn of 360 degrees ?? two digital 12-bit absolute outputs: - serial interface - pulse width modulated (pwm) output figure 1. as5145 automotive rotary encoder ic ?? three incremental outputs ?? quadrature a/b/i (10 or 12 bit) and index output signal (pre- programmed versions available as5145a for 10-bit and as5145b for 12-bit) ?? user programmable zero position ?? failure detection mode for magnet placement, monitoring, and loss of power supply ?? red-yellow-green indicators display placement of magnet in z- axis ?? serial read-out of multiple interconnected as5145 devices using daisy chain mode ?? tolerant to magnet misalignment and gap variations ?? wide temperature range: - 40oc to +150oc ?? fully automotive qualified to aec-q100, grade 0 ?? small pb-free package: ssop 16 (5.3mm x 6.2mm) 3 applications the device is ideal for industrial applications like contactless rotary position sensing and robotics; automotive applications like steering wheel position sensing, transmission gearbox encoder, head light position control, torque sensing, valve position sensing and replacement of high end potentiometers. dsp hall array & frontend amplifier absolute interface (ssi) incremental interface sin cos ang mag magincn magdecn do pwm clk dtest1_a dtest2_b mode_index pdio csn pwm interface otp register vdd5v vdd3v3 ldo 3.3v mux as5145
www.ams.com/as5145 revision 1.17 2 - 36 as5145 datasheet - contents contents 1 general description ............................................................................................................ ...................................................... 1 2 key features................................................................................................................... .......................................................... 1 3 applications................................................................................................................... ............................................................ 1 4 pin assignments ................................................................................................................ ....................................................... 4 4.1 pin descriptions.......................................................................................................... .......................................................................... 4 5 absolute maximum ratings ....................................................................................................... ............................................... 6 6 electrical characteristics..................................................................................................... ...................................................... 7 6.1 magnetic input specification.............................................................................................. ................................................................... 8 6.2 system specifications ..................................................................................................... ..................................................................... 9 7 timing characteristics ......................................................................................................... ................................................... 11 8 detailed description........................................................................................................... ..................................................... 12 8.1 mode_index pin............................................................................................................ ...................................................................... 12 8.1.1 synchronous serial interface (ssi) ...................................................................................... ..................................................... 13 8.1.2 incremental mode ........................................................................................................ .............................................................. 14 8.1.3 sync mode............................................................................................................... .................................................................. 16 8.1.4 sin/cosine mode ......................................................................................................... .............................................................. 16 8.1.5 daisy chain mode ........................................................................................................ ............................................................. 16 8.2 pulse width modulation (pwm) output....................................................................................... ....................................................... 17 8.2.1 changing the pwm frequency.............................................................................................. .................................................... 18 8.3 analog output............................................................................................................. ........................................................................ 18 9 application information ........................................................................................................ ................................................... 19 9.1 programming the as5145 .................................................................................................... .............................................................. 19 9.1.1 zero position programming ............................................................................................... ........................................................ 19 9.1.2 otp memory assignment................................................................................................... ....................................................... 20 9.1.3 user selectable settings ................................................................................................ ........................................................... 20 9.1.4 otp default setting..................................................................................................... .............................................................. 21 9.1.5 redundancy.............................................................................................................. ................................................................. 21 9.1.6 redundant programming option ............................................................................................ ................................................... 22 9.1.7 otp register entry and exit condition ................................................................................... .................................................. 22 9.2 alignment mode............................................................................................................ ...................................................................... 23 9.3 3.3v / 5v operation ....................................................................................................... ..................................................................... 24 9.4 selecting proper magnet ................................................................................................... ................................................................. 24 9.4.1 physical placement of the magnet ........................................................................................ .................................................... 25 9.4.2 magnet placement........................................................................................................ ............................................................. 26 9.5 failure diagnostics ....................................................................................................... ...................................................................... 26 9.5.1 magnetic field strength diagnosis ....................................................................................... ..................................................... 26 9.5.2 power supply failure detection .......................................................................................... ...................................................... 26 9.6 angular output tolerances ................................................................................................. ................................................................ 26 9.6.1 accuracy ................................................................................................................ .................................................................... 26 9.6.2 transition noise........................................................................................................ ................................................................. 28 9.6.3 high speed operation .................................................................................................... ........................................................... 28 9.6.4 propagation delays ...................................................................................................... ............................................................. 28 9.6.5 internal timing tolerance ............................................................................................... ........................................................... 29 9.6.6 temperature ............................................................................................................. ................................................................. 29 9.6.7 accuracy over temperature ............................................................................................... ....................................................... 29
www.ams.com/as5145 revision 1.17 3 - 36 as5145 datasheet - contents 9.7 differences between AS5145H, as5145a, as5145b and as5145i ................................................................. ................................. 29 10 package drawings and markings .................................................................................................. ....................................... 30 10.1 recommended pcb footprint................................................................................................ .......................................................... 32 11 ordering information ........................................................................................................... .................................................. 35
www.ams.com/as5145 revision 1.17 4 - 36 as5145 datasheet - pin assignments 4 pin assignments figure 2. pin assignments (top view) 4.1 pin descriptions the following ssop16 shows the description of each pin of the st andard ssop16 package (shrink small outline package, 16 leads, body size: 5.3mm x 6.2mmm; (see figure 2) . table 1. pin descriptions pin name pin number pin type description magincn 1 digital output open drain magnet field magnitude increase. active low. indicates a distance reduction between the magnet and the device surface. (see table 9) magdecn 2 magnet field magni tude decrease. active low. indicates a distance increase between the device and the magnet. (see table 9) dtest1_a 3 digital output test output in default mode dtest2_b 4 test output in default mode nc 5 - must be left unconnected mode_index 6 digital input/output pull-down select between slow (open, low: v ss ) and fast (high) mode. internal pull- down resistor (10k ). v ss 7 supply pin negative supply voltage (gnd) pdio 8 digital input pull-down otp programming input and data input for daisy chain mode. pin has an internal pull-down resistor (74k ). connect this pin to vss if programming is not required. do 9 digital output/ tri-state data output of synchronous serial interface 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 1 magincn magdecn dtest1_a dtest2_b nc vss pdio do clk csn pwm nc nc vdd3v3 vdd5v as5145 mode_index
www.ams.com/as5145 revision 1.17 5 - 36 as5145 datasheet - pin assignments pin 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. furthermor e those indicators can also be used for contact-less push-button functionality. pin 3 and 4 are multi function pins for sync mode, sin/cosine mode and incremental mode. pin 6 mode_index allows switching between filtered (slow) and unfiltered (fast mode). in incremental mode, the pin changes from input to output and provides the index pulse information. a change of the mode during operation is not allowed. the setup must be constant duri ng power up and during operation. pins 7, 15, and 16 are supply pins, pins 5, 13, and 14 are for internal use and must not be connected. pin 8 (pdio) is used to program the zero-position into the otp (see page 19) . this pin is also used as digital input to shift serial data through the device in daisy chain configuration, (see page 14) . pin 11 chip select (csn; active low) selects a device within a network of as5145 encoders and initiates serial data transfer. a logic high at csn puts the data output pin (do) to tri-state and terminates serial data transfer. this pin is also used for alignment mode (see alignment mode on page 23) and programming mode (see programming the as5145 on page 19) . pin 12 allows a single wire output of the 12-bit absolute position value. the value is encoded into a pulse width modulated sig nal with 1s pulse width per step (1s to 4096s over a full turn). by using an external low pass filter, the digital pwm signal is converted into an analog voltage, e.g. for making a direct replacement of potentiometers possible. clk 10 digital input, schmitt- trigger input clock input of synchronous serial interface; schmitt-trigger input csn 11 digital input pull- down, schmitt-trigger input chip select. active low. schmitt-trigger input, internal pull-up resistor (50k ) pwm 12 digital output pulse width modulation nc 13 - must be left unconnected nc 14 - must be left unconnected vdd3v3 15 supply pin 3v-regulator output, internally regulated from vdd5v. connect to vdd5v for 3v supply voltage. do not load externally. vdd5v 16 supply pin positive supply voltage, 3.0v to 5.5v table 1. pin descriptions pin name pin number pin type description
www.ams.com/as5145 revision 1.17 6 - 36 as5145 datasheet - absolute maximum ratings 5 absolute maximum ratings stresses beyond those listed in table 2 may cause permanent damage to the device. these are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in section 6 electrical characteristics on page 7 is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. table 2. absolute maximum ratings parameter min max units comments electrical parameters dc supply voltage at pin v dd 5v -0.3 7 v dc supply voltage at pin v dd 3v3 5 v input pin voltage -0.3 v dd 5v +0.3 v except v dd 3v3 input current (latchup immunity) -100 100 ma norm: eia/jesd78 class ii level a electrostatic discharge electrostatic discharge 2 kv norm: jesd22-a114e temperature ranges and storage conditions storage temperature -55 150 oc min -67of; max +302of package body temperature 260 oc the reflow peak soldering temperature (body temperature) specified is in accordance with ipc/ jedec j-std-020 ?moisture/reflow sensitivity classification for non-hermetic solid state surface mount devices?. the lead finish for pb-free leaded packages is matte tin (100% sn). humidity non-condensing 5 85 % moisture sensitive level (msl) 3 represents a maximum floor time of 168h
www.ams.com/as5145 revision 1.17 7 - 36 as5145 datasheet - electrical characteristics 6 electrical characteristics t amb = -40 to +150oc, v dd 5v = 3.0-3.6v (3v operation) v dd 5v = 4.5-5.5v (5v operation) unless otherwise noted. also valid for version i. table 3. electrical characteristics symbol parameter condition min typ max unit operating conditions t amb ambient temperature version h/a/b -40 +150 oc i supp supply current 16 21 ma v dd 5v supply voltage at pin v dd 5v 5v operation 4.5 5.0 5.5 v v dd 3v3 voltage regulator output voltage at pin v dd 3v3 3.0 3.3 3.6 v dd 5v supply voltage at pin v dd 5v 3.3v operation (pin v dd 5v and v dd 3v3 connected) 3.0 3.3 3.6 v v dd 3v3 supply voltage at pin v dd 3v3 3.0 3.3 3.6 v on power-on reset thresholds on voltage; 300mv typ. hysteresis dc supply voltage 3.3v ( v dd 3v3) 1,37 2.2 2.9 v v off power-on reset thresholds off voltage; 300mv typ. hysteresis 1.08 1.9 2.6 programming conditions v prog programming voltage voltage applied during programming 3.3 3.6 v v progoff programming voltage off level line must be discharged to this level 0 1 v i prog programming current current during programming 100 ma r programme d programmed fuse resistance (log 1) 10a max. current @ 100mv 100k ? r unprogram med unprogrammed fuse resistance (log 0) 2ma max. current @ 100mv 50 100 dc characteristics cmos schmitt-trigger i nputs: clk, csn (csn = internal pull-up) v ih high level input voltage normal operation 0.7 * v dd 5v v v il low level input voltage 0.3 * v dd 5v v v ion- v ioff schmitt trigger hysteresis 1 v i leak input leakage current clk only -1 1 a i il pull-up low level input current csn only, v dd 5v: 5.0v -30 -100 dc characteristics cmos / program input: pdio v ih high level input voltage 0.7 * v dd 5v v dd 5v v v prog 1 high level input voltage during programming 3.3 3.6 v v il low level input voltage 0.3 * v dd 5v v i il high level input current v dd 5v: 5.5v 30 100 a dc characteristics cmos output open drain: magincn, magdecn i oz open drain leakage current 1 a v ol low level output voltage vss + 0.4 v
www.ams.com/as5145 revision 1.17 8 - 36 as5145 datasheet - electrical characteristics 6.1 magnetic input specification t amb = -40 to +150c, v dd 5v = 3.0 to 3.6v (3v operation) v dd 5v = 4.5 to 5.5v (5v operation) unless otherwise noted. also valid for version i. two-pole cylindrical diametrically magnetized source: i o output current v dd 5v: 4.5v 4 ma v dd 5v: 3v 2 dc characteristics cmos output: pwm v oh high level output voltage v dd 5v ? 0.5 v v ol low level output voltage vss +0.4 v i o output current v dd 5v: 4.5v 4 ma v dd 5v: 3v 2 dc characteristics cmos output: a, b, index v oh high level output voltage v dd 5v ? 0.5 v v ol low level output voltage vss +0.4 v i o output current v dd 5v: 4.5v 4 ma v dd 5v: 3v 2 dc characteristics tri-state cmos output: do v oh high level output voltage v dd 5v ? 0.5 v v ol low level output voltage vss +0.4 v i o output current v dd 5v: 4.5v 4 ma v dd 5v: 3v 2 i oz tri-state leakage current 1 a 1. either with 3.3v or 5v supply. table 4. magnetic input specification symbol parameter condition min typ max unit d mag diameter recommended magnet: ? 6mm x 2.5mm for cylindrical magnets 46 mm t mag thickness 2.5 mm b pk magnetic input field amplitude required vertical component of the magnetic field strength on the die?s surface, measured along a concentric circle with a radius of 1.1mm 45 75 mt b off magnetic offset constant magnetic stray field 10 mt field non-linearity including offset gradient 5 % f mag_abs input frequency (rotational speed of magnet) 153 rpm @ 4096 positions/rev; fast mode 2.54 hz 38 rpm @ 4096 positions/rev; slow mode 0.63 table 3. electrical characteristics symbol parameter condition min typ max unit
www.ams.com/as5145 revision 1.17 9 - 36 as5145 datasheet - electrical characteristics 6.2 system specifications t amb = -40 to +150c, v dd 5v = 3.0 to 3.6v (3v operation) v dd 5v = 4.5 to 5.5v (5v operation) unless otherwise noted. also valid for version i. disp displacement radius max. offset between defined device center and magnet axis (see figure 19) 0.25 mm ecc eccentricity eccentricity of magnet center to rotational axis 100 m recommended magnet material and temperature drift ndfeb (neodymium iron boron) -0.12 %/k smco (samarium cobalt) -0.035 table 5. input specification symbol parameter condition min typ max unit res resolution 0.088 deg 12 bit inl opt integral non-linearity (optimum) maximum error with respect to the best line fit. centered magnet without calibration, t amb =25 oc. 0.5 deg inl temp integral non-linearity (optimum) maximum error with respect to the best line fit. centered magnet without calibration, t amb = -40 to +150 o c 0.9 deg inl integral non-linearity best line fit = (err max ? err min ) / 2 over displacement tolerance with 6mm diameter magnet, without calibration, t amb = -40 to +150oc 1.4 deg dnl differential non-linearity 12-bit, no missing codes 0.044 deg tn transition noise 1 sigma, fast mode (mode = 1) 0.06 deg rms 1 sigma, slow mode (mode = 0 or open) 0.03 t pwrup power-up time fast mode (mode = 1); until status bit ocf = 1 20 ms slow mode (mode = 0 or open); until ocf = 1 80 t delay system propagation delay absolute output : delay of adc, dsp and absolute interface fast mode (mode = 1) 96 s slow mode (mode = 0 or open) 384 t delayinc system propagation delay incremental output as5145a and as5145b: delay of adc, dsp and incremental interface only fast mode possible 192 s f s internal sampling rate for absolute output: t amb = 25 o c, slow mode (mode=0 or open) 2.48 2.61 2.74 khz t amb = -40 to +150 o c, slow mode (mode=0 or open) 2.35 2.61 2.87 f s internal sampling rate for absolute output t amb = 25 o c, fast mode (mode = 1) 9.90 10.42 10.94 khz t amb = -40 to +150 o c, fast mode (mode=1) 9.38 10.42 11.46 clk/sel read-out frequency max. clock frequency to read out serial data 1 mhz table 4. magnetic input specification symbol parameter condition min typ max unit
www.ams.com/as5145 revision 1.17 10 - 36 as5145 datasheet - electrical characteristics figure 3. 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. 180 360 0 0 512 1023 10bit code 0 1 2 0.35 inl ideal curve actual curve tn 512 1023 dnl+1lsb [degrees]
www.ams.com/as5145 revision 1.17 11 - 36 as5145 datasheet - timing characteristics 7 timing characteristics t amb = -40 to +150 oc, v dd 5v = 3.0 to 3.6v (3v operation) v dd 5v = 4.5 to 5.5v (5v operation), unless otherwise noted. also valid for version i. table 6. timing characteristics symbol parameter conditions min typ max units synchronous serial interface (ssi) t doactive data output activated (logic high) time between falling edge of csn and data output activated 100 ns t clkfe first data shifted to output register time between falling edge of csn and first falling edge of clk 500 ns t clk/2 start of data output rising edge of clk shifts out one bit at a time 500 ns t dovalid data output valid time between rising edge of clk and data output valid 413 ns t dotristate data output tri-state after the last bit do changes back to ?tri- state? 100 ns t csn pulse width of csn csn =high; to initiate read-out of next angular position 500 ns f clk read-out frequency clock frequency to read out serial data >0 1 mhz pulse width modulation output f pwm pwm frequency signal period = 4098s 10% at t amb = -40 to +150oc 220 244 268 hz pw min minimum pulse width position 0d; angle 0 degree 0.90 1 1.10 s pw max maximum pulse width position 4098d; angle 359.91 degrees 3686 4096 4506 s programming conditions t prog programming time per bit time to prog. a single fuse bit 10 20 s t charge refresh time per bit time to charge the cap after t prog 1s f load load frequency data can be loaded at n x 2s 500 khz f read read frequency read the data from the latch 2.5 mhz f write write frequency write the data to the latch 2.5 mhz
www.ams.com/as5145 revision 1.17 12 - 36 as5145 datasheet - detailed description 8 detailed description the as5145 is manufactured in a cmos standard process and uses a spinning current hall technology for sensing the magnetic fiel d distribution across the surface of the chip. the integrated hall elements are placed around the center of the device and delive r 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 as5145 provides accurate hi gh-resolution absolute angular position information. for this purpose a coor dinate rotation digital computer (cordic) calculates the angle an d 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 magn et towards or away from the device?s surface. a small low cost diametrically magnetized (two-pole) standard magnet provides the angular po sition information (see figure 18) . the as5145 senses the orientation of the magnetic field and calculates a 12-bit binary code. this code can be accessed via a sy nchronous serial interface (ssi). in addition, an absolute angular representation is given by a pulse width modulated signal at pin 12 (p wm). this pwm signal output also allows the generation of a direct proportional analog voltage, by using an external low-pass-filter. the as5 145 is tolerant to magnet misalignment and magnetic stray fields due to differential measurement technique and hall sensor conditioning circuitry. figure 4. typical arrangement of as5145 and magnet 8.1 mode_index pin the mode_index pin activates or deactivates an internal filter that is used to reduce the analog output noise. activating the filter (mode pin = low or open) provides a reduced output noise of 0.03o rms. at the same time, the output delay is increased to 384s. this mode is recommended for high precision, low speed applications. deactivating the filter (mode pin = high) reduces the output delay to 96s and provides an output noise of 0.06o rms. this mode is recommended for higher speed applications. setup the mode pin affects the following parameters: note: a change of the mode during operation is not allowed. the setup must be constant during power up and during operation. table 7. slow and fast mode parameters parameter slow mode (mode= low or open) fast mode (mode=high, v dd = 5v) sampling rate 2.61 khz (384 s) 10.42 khz (96s) transition noise (1 sigma) 0.03o rms 0.06o rms output delay 384s 96s maximum speed @ 4096 samples/rev 38 rpm 153 rpm maximum speed @ 1024 samples/rev 153 rpm 610 rpm maximum speed @ 256 samples/rev 610 rpm 2441 rpm maximum speed @ 64 samples/rev 2441 rpm 9766 rpm
www.ams.com/as5145 revision 1.17 13 - 36 as5145 datasheet - detailed description 8.1.1 synchronous serial interface (ssi) figure 5. synchronous 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 i nitiated. ?? after a minimum time t clk fe , data is latched into the output shift register with the first falling edge of clk. ?? each subsequent rising clk edge shifts out one bit of data. ?? the serial word contains 18 bits, the first 12 bits are the angular information d[11:0], the subsequent 6 bits contain system i nformation, about the validity of data such as ocf, cof, lin, parity and magnetic field status (increase/decrease). ?? a subsequent measurement is initiated by a ?high? pulse at csn with a minimum duration of t csn . data content d11:d0 absolute angular position data (msb is clocked out first) ocf (offset compensation finished), logic high indicates the finished offset compensation algorithm cof (cordic overflow), logic high indicates an out of range error in the cordic part. when this bit is set, the data at d11:d0 is invalid. the absolute output maintains the last valid angular value. this alarm can be resolved by bringing the magnet within the x-y-z tolerance limits. lin (linearity alarm), logic high indicates that the input field generates a critical output linearity. when this bit is set, the data at d11:d0 can still be used, but can contain invalid data. this warning can be resolved by bring ing the magnet within the x-y-z tolerance limits. even parity bit for transmission error detection of bits 1?17 (d11?d0, ocf, cof, lin, maginc, magdec) placing the magnet above the chip, angular values increase in clockwise direction by default. data d11:d0 is valid, when the status bits have the following configurations: note: maginc=magdec=1 is only recommended in yellow mode (see table 9) table 8. status bit outputs ocf cof lin mag inc mag dec parity 10 0 00 even checksum of bits 1:15 01 10 11 csn clk do t do valid angular position data t do active status bits t do tristate t csn t clk fe t clk fe t clk/2 1 d9 d8 d7 d6 d5 d4 d3 d2 d1 d0 ocf cof lin mag inc mag dec even par 8 18 1 d11 d10 d11
www.ams.com/as5145 revision 1.17 14 - 36 as5145 datasheet - detailed description z-axis range indication (push button f eature, red/yellow/green indicator). the as5145 provides several options of detecting movement and distance of the magnet in the z-direction. signal indicators magincn and magdecn are available both as hardware pi ns (pins #1 and 2) and as status bits in the serial data stream (see figure 5) . in the default state, the status bits maginc, magdec and pins magincn, magdecn have the following function: note: pin 1 (magincn) and pin 2 (magdecn) are active low via open drain output and require an external pull-up resistor. if the magne tic field is in range, both outputs are turned off. the two pins can also be combined with a single pull-up resistor. in this case, the signal is high when the magnetic field is i n range. it is low in all other cases (see table 9) . 8.1.2 incremental mode the as5145 has an internal interpolator block. this function is used if the input magnetic field is to fast and a code position is missing. in this case an interpolation is done. with the otp bits outputmd0 and outputmd1 a specific mode can be selected. for the available pre-programmed incremental version s (10-bit and 12-bit), these bits are set during test at ams. these settings are permanent and can not be recovered. a change of the incremental mode (write command) during operation could cause problems. a power-on-reset in between is recommen ded. table 9. magnetic field strength red-yellow-green indicator status bits hardware pins otp: mag compen = 1 (red-yellow-green) mac inc mag dec lin mac incn mag decn description 000offoff no distance change magnetic input field ok (green range, ~45?75mt) 110onoff yellow range: magnetic field is ~ 25?45mt or ~75?135mt. the as5145 can still be operated in this range, but with slightly reduced accuracy. 111onon red range: magnetic field is ~<25mt or >~135mt. it is still possible to operate the as5145 in the red range, but not recommended. all other combinations n/a n/a not available table 10. incremental resolution mode description output md1 output md0 resolution dtest1_a and dtest2_b pulses index width default mode as5145 function dtest1_a and dtest2_b are not used. the mode_index pin is used for selection of the decimation rate (low speed/high speed). 00 10-bit incremental mode (low dnl) dtest1_a and dtest2_b are used as a and b signal. in this mode the mode_index pin is switched from input to output and will be the index pin. the decimation rate is set to 64 (fast mode) and cannot be changed from external. 0 1 10 256 1/3 lsb 12-bit incremental mode (high dnl) 1 0 12 1024 sync mode in this mode a control signal is switched to dtest1_a and dtest2_b . 11
www.ams.com/as5145 revision 1.17 15 - 36 as5145 datasheet - detailed description 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 ( ). 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=i ndex = high) can be used as an indicator for the external controller to shorten the waiting time at power-up. instead of waiting for the specifi ed maximum power up-time (0), the controller can start requesting data from the as5145 as soon as the state (a=b=index = high) is cleared. ?? csn = high or open at power-up: in this mode, the incremental ou tputs (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 mi crocontroller is ready to receive data. figure 6. incremental output the hysteresis trimming is done at the final test (factory trimming) and set to 4 lsb, related to a 12-bit number. incremental output hysteresis. to avoid flickering incremental outputs at a stationary magnet position, a hysteresis is introduced. in case of a rotational direction change, the incremental outputs have a hysteresis of 4 lsb. regardless of the programmed incremental resolution, the hysteresis of 4 lsb always corresponds to the highest resolution of 12-bit. in absolute terms, the hysteresis is set to 0.35 de grees for all resolutions. for constant rotational directions, every magnet position change is indicated at the incremental outputs (see figure 7) . for example, if the magnet turns clockwise from position ?x+3? to ?x+4?, the incremental output would also indicate this position accordingl y. a change of the magnet?s rotational direction back to position ?x+3? means that the incremental output still remains unchanged for the duration of 4 lsb, until position ?x+2?is reached. following this direction, the incremen tal outputs will again be updated with every change of the magn et position. figure 7. hysteresis window for incremental outputs r ext 5k mode_index d test2_b d test1_a 1 lsb programmed zero position clockwise 3 lsb counter clockwise magnet position hysteresis : 0.35 x +2 incremental output indication clockwise direction counterclockwise direction x +4 x x x +2 x +4 x +5 x +3 x +1 x +1 x +3 x +6 x +5 x +6
www.ams.com/as5145 revision 1.17 16 - 36 as5145 datasheet - detailed description incremental output validity. during power on the incremental output is kept stable high until the offset compensation is finished and the csn is low (internal pull up) the first time. in quadrature mode a = b = index = high indicates an invalid output. if the inter polator recognizes a difference larger than 128 steps between two samples it holds the last valid state. the interpolator synchronizes up again with the next valid difference. this avoids undefined output burst, e.g. if no magnet is present. 8.1.3 sync mode this mode is used to synchronize the external electronic with the as5145. in this mode two signals are provided at the pins dte st1_a and dtest2_b. by setting of md0=1 and md1=1 in the otp register, the sync mode will be activated. figure 8. dtest1_a and dtest2_b every rising edge at dtest1_a indicates that new data in the device is available. with this signal it is possible to trigger an external customer microcontroller (interrupt) and start the ssi readout. dtest2_b indicates the phase of available data. 8.1.4 sin/cosine mode this mode can be enabled by setting the otp factory-bit fs2. if this mode is activated the 16 bit sinus and 16 bit cosines digi tal data of both channels will be switched out. due to the high resolution of 16 bits of the data stream an accurate calculation can be done ext ernally. in this mode the open drain outputs of dtest1_a and dtest2_b are switched to push-pull mode. at pin magdecn the clock impulse, at pin magincn the enable pulse will be switched out. the pin pwm indica tes, which phase of signal is being presented. the mode isn?t available in the default mode. 8.1.5 daisy chain mode the daisy chain mode allows connection of several as5145s in series, while still keeping just one digital input for data transf er (see ?data in? in figure 9 ). this mode is accomplished by connecting the data output (do; pin 9) to the data input (pdio; pin 8) of the subsequent device . the serial data of all connected devices is read from the do pin of the first device in the chain. the length of the serial bit str eam increases with every connected device, it is n * (18+1) bits: n= number of devices. e.g. 38 bit for two devices, 57 bit for three devices, etc. the last data bit of the first device (parity) is followed by a dummy bit and the first data bit of the second device (d11), et c. (see figure 10) . figure 9. daisy chain hardware configuration dtest1_a dtest1_b 400s (100s) csn csn csn csn clk clk clk clk data in as5145 1 st device as5145 2 nd device as5145 last device c do do do pdio pdio pdio
www.ams.com/as5145 revision 1.17 17 - 36 as5145 datasheet - detailed description figure 10. daisy chain mode data transfer 8.2 pulse width modul ation (pwm) output the as5145 provides a pulse width modulated output (pwm), whose duty cycle is proportional to the measured angle. for angle pos ition 0 to 4094 position = (eq 1) examples: 1. an angle position of 180 will generate a pulse width ton = 2049s and a pause toff of 2049 s resulting in position = 2048 after the cal - culation: 2049 * 4098 / (2049 + 2049) -1 = 2048 2. an angle position of 359.8 will generate a pulse width ton = 4095s and a pause toff of 3 s resulting in position = 4094 after the cal - culation: 4095 * 4098 / (4095 + 3) -1 = 4094 exception: 1. an angle position of 359.9 will generate a pulse width ton = 4097s and a pause toff of 1 s resulting in position = 4096 after the cal - culation: 4097 * 4098 / (4097 + 1) -1 = 4096 the pwm frequency is internally trimmed to an accuracy of 5% (10% over full temperature range). this tolerance can be cancell ed by measuring the complete duty cycle as shown above. figure 11. pwm output signal csn clk do t do valid angular position data t do active status bits t clk fe t clk/2 1 d9 d8 d7 d6 d5 d4 d3 d2 d1 d0 ocf cof lin mag inc mag dec even par 8 18 d d11 1 2 3 d10 d9 angular position data 1 st device 2 nd device d10 d11 t on 4098 ? t on t off + () ------------------------- 1 ? 4098s 4097s 1/f pwm pw max pw min 359.91 deg (pos 4095) 0 deg (pos 0) angle 1s
www.ams.com/as5145 revision 1.17 18 - 36 as5145 datasheet - detailed description 8.2.1 changing the pwm frequency the pwm frequency of the as5145 can be divided by two by setting a bit (pwmhalfen) in the otp register (see programming the as5145 on page 19) . with pwmhalfen = 0 the pwm timing is as shown in table 11 : when pwmhalfen = 1, the pwm timing is as shown in table 12 : 8.3 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 = v dd 5v. using this method, the as5145 can be used as direct replacement of potentiometers. figure 12. simple 2nd order passive rc low pass filter figure 11 shows an example of a simple passive low pass filter to generate the analog output. r1,r2 10k c1,c2 2.2f / 6v (eq 2) r1 should be greater than or equal to 4k7 to avoid loading of the pwm output. larger values of rx and cx will provide better fi ltering and less ripple, but will also slow down the response time. table 11. pwm signal parameters (default mode) symbol parameter typ unit note f pwm pwm frequency 244 hz signal period: 4097s pw min min pulse width 1 s - position 0d - angle 0 deg pw max max pulse width 4097 s - position 4095d - angle 359.91 deg table 12. pwm signal parameters with half frequency (otp option) symbol parameter typ unit note f pwm pwm frequency 122 hz signal period: 8194s pw min min pulse width 2 s - position 0d - angle 0 deg pw max max pulse width 8194 s - position 4095d - angle 359.91 deg r1 r2 analog out pin12 pwm pin7 vss c1 c2 vdd 0v 0o 360o
www.ams.com/as5145 revision 1.17 19 - 36 as5145 datasheet - application information 9 application information the benefits of as5145 are as follows: ?? complete system-on-chip ?? flexible system solution provides absolute and pwm outputs simultaneously ?? ideal for applications in harsh environments due to contactless position sensing ?? no calibration required ?? no temperature compensation necessary 9.1 programming the as5145 after power-on, programming the as5145 is enabled with the rising edge of csn with pdio = high and clk = low. the as5145 programming is a one-time-programming (otp) method, based on poly silicon fuses. the advantage of this method is tha t a programming voltage of only 3.3v to 3.6v is required for programming (either with 3.3v or 5v supply). the otp consists of 52 bits, of which 21 bits are available for user programming. the remaining 31 bits contain factory setting s and a unique chip identifier (chip-id). a single otp cell can be programmed only once. per default, the cell is ?0?; a programmed cell will contain a ?1?. while it is not possible to reset a programmed bit from ?1? to ?0?, multiple otp writes are possi ble, as long as only unprogrammed ?0?-bits are programmed to ?1? . independent of the otp programming, it is possible to overwrite t he otp register temporarily with an otp write command at any t ime. this setting will be cleared and overwritten with the hard programmed ot p settings at each power-up sequence or by a load operation. use application note an514x_10 to get more information about the programming options. the otp memory can be accessed in the following ways: ?? load operation: the load operation reads the otp fuses and loads the contents into the otp register. a load operation is automatically executed after each power-on-reset. ?? write operation: the write operation allows a temporary modification of the otp register. it does not program the otp. this operation can be invoked multiple times and will remain set while the chip is supplied with power and while the otp register is not modified with another write or load operation. ?? read operation: the read operation reads the contents of the otp register, for example to verify a write command or to read the otp memory after a load command. ?? program operation: the program operation writes the contents of the otp register permanently into the otp rom. ?? analog readback operation: the analog readback operation allows a quantifiable verification of the programming. for each pro- grammed or unprogrammed bit, there is a representative analog value (in essence, a resistor value) that is read to verify wheth er a bit has been successfully programmed or not. 9.1.1 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 adj usted to the mechanical zero position. once the assembly is completed, the mechanical and electrical zero positions can be matched by softwa re. any position within a full turn can be defined as the permanent new zero position. for zero position programming, the magnet is turned to the mechanical zero position (e.g. the ?off?-position of a rotary switch ) and the actual angular value is read. this value is written into the otp register bits z35:z46 (see figure 13) . note: the zero position value can also be modified before programming, e.g. to program an electrical zero position that is 180o (half turn) from the mechanical zero position, just add 2048 to the value read at the mechanical zero position and program the new value in to the otp register.
www.ams.com/as5145 revision 1.17 20 - 36 as5145 datasheet - application information 9.1.2 otp memory assignment 9.1.3 user selectable settings the as5145 allows programming of the following user selectable options: - pwmhalfen_indexwidth : setting this bit, the pwm pulse will be divided by 2, in case of quadrature incremental mode a/b/index setting of index impulse width from 1 lsb to 3lsb - output md0: setting this bit enables sync- or 10-bit incremental mode (see table 10) . - output md1: setting this bit enables sync- or 12-bit incremental mode (see table 10) . - z [11:0]: programmable zero / index position table 13. otp bit assignment bit symbol function mbit1 factory bit 1 51 pwmhalfen_index width pmw frequency index pulse width customer section 50 magcompen alarm mode (programmed by ams to 1) 49 pwmdis disable pwm 48 output md0 default, 10-bit inc, 12-bit inc sync mode 47 output md1 46 z0 12-bit zero position :: 35 z11 34 ccw direction 33 ra0 redundancy address :: 29 ra4 28 fs 0 factory bit factory section 27 fs 1 26 fs 2 25 fs 3 24 fs 4 23 fs 5 :: 20 fs 8 19 fs 9 18 fs 10 17 chipid0 18-bit chip id id section 16 chipid1 :: 0 chipid17 mbit0 factory bit 0
www.ams.com/as5145 revision 1.17 21 - 36 as5145 datasheet - application information - ccw: counter clockwise bit ccw=0 ? angular value increases in clockwise direction ccw=1 ? angular value increases in counterclockwise direction - ra [4:0]: redundant address: an otp bit location addressed by this address is always set to ?1? independent of the corresponding original otp bit setting 9.1.4 otp default setting the as5145 can also be operated without programming. the default, un-programmed setting is: - output md0, output md1: 00= default mode - z0 to z11: 00 = no programmed zero position - ccw: 0 = clockwise operation - ra4 to ra0: 0 = no otp bit is selected - magcompen: 1 = the green/yellow mode is enabled 9.1.5 redundancy for a better programming reliability a redundancy is implemented. in case when the programming of one bit failed this function can be used. with an address ra(4:0) one bit can be selected and programmed. table 14. redundancy addressing address pwmhalfen_indexwidth magcompen pwmdis output md0 output md1 z0 z1 z2 z3 z4 z5 z6 z7 z8 z9 z10 z11 ccw 00000 000000000000000000 00001 1 00000000000000000 00010 0 1 0000000000000000 00011 0 0 1 000000000000000 00100 0 0 0 1 00000000000000 00101 0000 1 0000000000000 00110 00000 1 000000000000 00111 000000 1 00000000000 01000 0000000 1 0000000000 01001 00000000 1 000000000 01010 000000000 1 00000000 01011 0000000000 1 0000000 01100 00000000000 1 000000 01101 000000000000 1 00000 01110 0000000000000 1 0000 01111 00000000000000 1 000 10000 000000000000000 1 00 10001 0000000000000000 1 0 10010 00000000000000000 1 10101 111111111111111111
www.ams.com/as5145 revision 1.17 22 - 36 as5145 datasheet - application information 9.1.6 redundant programming option in addition to the regular programming, a redundant programming option is available. this option allows that one selectable otp bit can be set to ?1? (programmed state) by writing the location of that bit into a 5-bit address decoder. this address can be stored in bits ra4...ra0 in the otp user settings. example: setting ra4?0 to ?00001? will select bit 51 = pwhalfen_indexwidth, ?00010? selects bit 50 = magcompen, ?10010? selects bit 34 =ccw, etc. 9.1.7 otp register entry and exit condition for timing options, refer to programming the as5145 (page 19) . figure 13. otp access timing diagram to avoid accidental modification of the otp during normal operation, each otp access (load, write, read, program) requires a de fined entry and exit procedure, using the csn, pdio and clk signals as shown in figure 13 . figure 14. otp programming connection otp access setup condition operation mode selection exit condition csn pdio clk as5145 demoboard 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 1 magincn magdecn dtest1_a dtest2_b nc mode_ index vss pdio do clk csn pwm nc nc vdd3v3 vdd5v as5145 ic 1 7 2 3 4 5 6 1 10n 2.2f c cap only required for otp programming gnd prog csn do clk 5vusb vdd3v3 vss + 10f 2 3 1 gnd vss vprog 3.3 ? 4. 6 v only required for otp programming connect to usb interface on pc usb for programming , k eep these 6 wires as short as possible! max. length = 2 inches (5cm) 22k 3v3
www.ams.com/as5145 revision 1.17 23 - 36 as5145 datasheet - application information 9.2 alignment mode the alignment mode simplifies centering the magnet over the center of the chip to gain maximum accuracy. alignment mode can be enabled with the falling edge of csn while pdio = logic high (see figure 15) . the data bits d11-d0 of the ssi change to a 12-bit displacement amplitude output. a high value indicates large x or y displacement, but also higher absolute magnetic fie ld strength. the magnet is properly aligned, when the difference between highest and lowest value over one full turn is at a minimum. under normal conditions, a properly aligned magnet will result in a reading of less than 128 over a full turn. the magincn and magdecn indicators will be = 1 when the alignment mode reading is < 128. at the same time, both hardware pins m agincn (#1) and magdecn (#2) will be pulled to vss. a properly align ed magnet will therefore produce a magincn = magdecn = 1 signal th roughout a full 360o turn of the magnet. stronger magnets or short gaps between magnet and ic will show values larger than 128. these magnets are still properly aligned as long as the difference between highest and lowest value over one full turn is at a minimum. the alignment mode can be reset to normal operation by a power-on-reset (disconnect / re-connect power supply) or by a falling edge on csn with pdio = low. figure 15. enabling the alignment mode figure 16. exiting alignment mode pdio csn alignmode enable read-out via ssi 2s min. 2s min. pdio csn exit alignmode read-out via ssi
www.ams.com/as5145 revision 1.17 24 - 36 as5145 datasheet - application information 9.3 3.3v / 5v operation the as5145 operates either at 3.3v 10% or at 5v 10%. this is made possible by an internal 3.3v low-dropout (ldo) voltage regu lator. 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 v dd 3v3 with v dd 5v (see figure 17) . for 5v operation, the 5v supply is connected to pin v dd 5v, while v dd 3v3 (ldo output) must be buffered by a 1...10f capacitor, which is supposed to be placed close to the supply pin (see figure 17) with recommended 2.2f). note: the v dd 3v3 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 v dd 5v, as the i/o buffers are supplied from this pin. figure 17. connections for 5v / 3.3v supply voltages a buffer capacitor of 100nf is recommended in both cases close to pin v dd 5v. note that pin v dd 3v3 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 can lead to larger than normal j itter of the measured angle. 9.4 selecting proper magnet typically the magnet is 6mm in diameter and 2.5mm in height. magnetic materials such as rare earth alnico/smco5 or ndfeb are recommended. the magnetic field strength perpendicular to the die surface has to be in the range of 45mt?75mt (peak). the magnet?s field strength is verified using a gauss-meter. the magnetic field bv at a given distance, along a concentric circ le with a radius of 1.1mm (r1) is in the range of 45mt?75mt (see figure 18) . internal vdd ldo i n t e r f a c e vss vdd5v vdd3v3 100nf 4.5 - 5.5v + - 2.2 ... 10f do pwm clk csn pdio internal vdd ldo i n t e r f a c e vss vdd5v vdd3v3 3.0 - 3.6v + - do pwm clk csn pdio 100nf 5v operation 3.3v operation
www.ams.com/as5145 revision 1.17 25 - 36 as5145 datasheet - application information figure 18. typical magnet (6x3mm) and magnetic field distribution 9.4.1 physical placement of the magnet the best linearity can be achieved by placing the center of the magnet exactly over the defined center of the chip as shown in the drawing below: figure 19. defined chip center and magnet displacement radius magnet axis vertical field component (45?75mt) 0 360 360 bv vertical field component r1 concentric circle; radius 1.1mm r1 magnet axis typ. 6mm diameter s n area of recommended maximum mag- net misalignment defined center r d 3.9mm 3.9mm 2.4325mm 2.4325mm 1
www.ams.com/as5145 revision 1.17 26 - 36 as5145 datasheet - application information 9.4.2 magnet placement the magnet?s center axis must be aligned within a displacement radius rd of 0.25mm from the defined center of the ic. the magne t can be placed below or above the device. the distance can be chosen such that the magnetic field on the die surface is within the spec ified limits (see figure 19) . the typical distance ?z? between the magnet and the package surface is 0.5mm 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 stay s within the defined limits. a magnetic field outside the specified range still can be detected by the chip. but the out-of-range condition will be indicate d by magincn (pin 1) and magdecn (pin 2), (see table 1) . 9.5 failure diagnostics the as5145 also offers several diagnostic and failure detection features: 9.5.1 magnetic field strength diagnosis by software: the maginc and magdec status bits will both be high when the magnetic field is out of range. by hardware: pins #1 (magincn) and #2 (magdecn) are open-drain outputs and will both be turned on (= low with external pull-up resistor) when the magnetic field is out of range. if only one of the outputs are low, the magnet is either moving towards the chip (magi ncn) or away from the chip (magdecn). 9.5.2 power supply failure detection by software: if the power supply to the as5145 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 (~1 0k ) must be added between pin dio and vss at the receiving side. by hardware: the magincn and magdecn pins are open drain outputs and require external pull-up resistors. in normal operation, these pins are high ohmic and the outputs are high (see table 9) . in a failure case, either when the magnetic field is out of range of the power supply is missing, these outputs will become low. to ensure adequate low levels in case of a broken power supply to the as5145, the pull- up resistors (~10k ) from each pin must be connected to the positive supply at pin 16 (v dd 5v). 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. 9.6 angular output tolerances 9.6.1 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 = (errmax ? errmin)/2 is specified as better than 0.5 degrees @ 25oc (see figure 21) . misalignment of the magnet further reduces the accuracy. figure 20 shows an example of a 3d-graph displaying non-linearity over xy- misalignment. the center of the square xy-area corresponds to a centered magnet (see dot in the center of the graph). the x- an d y- axis extends to a misalignment of 1mm in both directions. the total misalignment area of the graph covers a square of 2x2mm (79x79m il) with a step size of 100m. for each misalignment step, the measurement as shown in figure 21 is repeated and the accuracy (errmax ? errmin)/2 (e.g. 0.25o in figure 21 ) is entered as the z-axis in the 3d-graph.
www.ams.com/as5145 revision 1.17 27 - 36 as5145 datasheet - application information figure 20. example of linearity error over xy misalignment the maximum non-linearity error on this example is better than 1 degree (inner circle) over a misalignment radius of ~0.7mm. f or 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 bette r 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 21. example of linearity error over 360 o -1000 -700 -400 -100 200 500 800 -1000 -800 -600 -400 -200 0 200 400 600 800 1000 0 1 2 3 4 5 6 x y -0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5 1 55 109 163 217 271 325 379 433 487 541 595 649 703 757 811 865 919 973 transition noise err max err min
www.ams.com/as5145 revision 1.17 28 - 36 as5145 datasheet - application information 9.6.2 transition noise transition noise is defined as the jitter in the transition between two steps. due to the nature of the measurement principle ( hall sensors + preamplifier + adc), there is always a certain degree of noise involved. this transition noise voltage results in an angular tr ansition noise at the outputs. it is specified as 0.06 degrees rms (1 sigma)x1 in fast mode (pin mode = high) and 0.03 degrees rms (1 sigma)x1 in slo w mode (pin mode = low or open). this is the repeatability of an indicated angle at a given mechanical position. the transition noise has different implications on the type of output that is used: ?? absolute output; ssi interface: the transition noise of the absolute output can be reduced by the user by implementing averaging of read- ings. an averaging of 4 readings will reduce the transition noise by 6db or 50%, e.g. from 0.03orms to 0.015orms (1 sigma) in s low mode. ?? pwm interface: if the pwm interface is used as an analog output by adding a low pass filter, the transition noise can be reduced by lower- ing the cutoff frequency of the filter. if the pwm interface is used as a digital interface with a counter at the receiving sid e, the transition noise can be further 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 15,000 rpm and higher). note: statistically, 1 sigma represents 68.27% of readings and 3 sigma represents 99.73% of readings. 9.6.3 high speed operation ?? sampling rate: the as5145 samples the angular value at a rate of 2.61k (slow mode) or 10.42k (fast mode, selectable by pin mode) samples per second. consequently, the absolute outputs are updated each 384s (96s in fast mode). at a stationary position of the mag- net, the sampling rate creates no additional error. ?? absolute mode: at a sampling rate of 2.6khz/10.4khz, the number of samples (n) per turn for a magnet rotating at high speed can be cal- culated by n slowmode = (eq 3) n fastmode = (eq 4) the upper speed limit in slow mode is ~6,000 rpm and ~30,000 rpm in fast mode. the only restriction at high speed is that there will be fewer samples per revolution as the speed increases (see table 7) . regardless of the rotational speed, the absolute angular value is always sampled at the highest resolution of 12-bit. ?? incremental mode: incremental encoders are usually required to produce no missing pulses up to several thousand rpm. therefore, the as5145 has a built-in interpolator, which ensures that there are no missing pulses at the incremental outputs for rotational sp eeds of up to 15,000 rpm, even at the highest resolution of 12 bits (4096 pulses per revolution). 9.6.4 propagation delays the propagation delay is the delay between the time that the sample is taken until it is converted and available as angular dat a. this delay is 96s in fast mode and 384s in slow mode. using the ssi interface for absolute data transmission, an additional delay must be considered, caused by the asynchronous samp ling (0 ? 1/ fsample) and the time it takes the external control unit to read and process the angular data from the chip (maximum clock rate = 1mhz, number of bits per reading = 18). angular error caused by propagation delay. a rotating magnet will cause an angular error caused by the output propagation delay. this error increases linearly with speed: e sampling = rpm * 6 * prop.delay (eq 5) where: esampling = angular error [o] rpm = rotating speed [rpm] prop.delay = propagation delay [seconds] note: since the propagation delay is known, it can be automatically compensated by the control unit processing the data from the as51 45. 60 rpm 384 () s ? ---------------------------------- - 60 rmp 96 s ? -------------------------- -
www.ams.com/as5145 revision 1.17 29 - 36 as5145 datasheet - application information 9.6.5 internal timing tolerance the as5145 does not require an external ceramic resonator or quartz. all internal clock timings for the as5145 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 tol erance influences the adc sampling rate and the pulse width of the pwm output: - absolute output; ssi interface: a new angular value is updated every 96s (typ) in fast mode and every 384s (typ) in slow mod e. - pwm output: a new angular value is updated every 384s (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 ton is used to measure the angle, the resulting value also has this timing tol erance. how- ever, this tolerance can be cancelled by measuring both ton and t off and calculating the angle from the duty cycle (see pulse width mod- ulation (pwm) output on page 17) position = (eq 6) 9.6.6 temperature magnetic temperature coefficient. one of the major benefits of the as5145 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 as5145 automatically compensates for the varying magnetic field strength over temperature. the magnet?s temperature drift does not need to be consid ered, as the as5145 operates with magnetic field strengths from 45?75mt. example : a ndfeb magnet has a field strength of 75mt @ ?40oc and a temperature coefficient of -0.12% per kelvin. the temperature chang e 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 a t 125oc. the as5145 can compensate for this temperature related field strength change automatically, no user adjustment is required. 9.6.7 accuracy over temperature the influence of temperature in the absolute accuracy is very low. while the accuracy is less than or equal to 0.5o at room te mperature, it can increase to less than or equal to 0.9o due to increasing noise at high temperatures. timing tolerance over temperature. the internal rc oscillator is factory trimmed to 5%. over temperature, this tolerance can increase to 10%. generally, the timing tolerance has no influence in the ac curacy or resolution of the syst em, 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 intern al oscillator. this influence however can be cancelled by measuring the complete pwm duty cycle instead of just the pwm pulse. 9.7 differences between as 5145h, as5145a and as5145b table 15. functional differences function AS5145H as5145a as5145b filtering mode selectable by customer via mode pin (see table 7) pre-defined to fast mode mode_index pin input. must be set hard wired on pcb output output incremental mode setting default disabled. can be enabled by customer via programming pre-defined to 2x256 ppr low-jitter (10-bit) pre-defined to 2x1024 ppr (12-bit) resolution absolute angle output (pwm and ssi) 12-bit angle t on 4097 ? t on t off + () ------------------------- 1 ?
www.ams.com/as5145 revision 1.17 30 - 36 as5145 datasheet - package drawings and markings 10 package drawin gs and markings the device is available in ssop 16 (5.3mm x 6.2mm). figure 22. package drawings and dimensions notes: 1. dimensions and tolerancing conform to asme y14.5m-1994 . 2. all dimensions are in millimeters. angles are in degrees. marking: yywwmzz. yy ww m zz last two digits of the manufacturing year manufacturing week plant identifier assembly traceability code symbol min nom max a 1.73 1.86 1.99 a1 0.05 0.13 0.21 a2 1.68 1.73 1.78 b 0.22 0.315 0.38 c 0.09 0.17 0.25 d 5.90 6.20 6.50 e 7.40 7.80 8.20 e1 5.00 5.30 5.60 e - 0.65 bsc - l 0.55 0.75 0.95 l1 - 1.25 ref - l2 - 0.25 bsc - r0.09 - - 0o 4o 8o n16
www.ams.com/as5145 revision 1.17 31 - 36 as5145 datasheet - package drawings and markings figure 23. vertical cross section of ssop-16 notes: 1. all dimensions in mm.
www.ams.com/as5145 revision 1.17 32 - 36 as5145 datasheet - package drawings and markings 10.1 recommende d pcb footprint figure 24. pcb footprint recommended footprint data symbol mm a9.02 b6.16 c0.46 d0.65 e5.01
www.ams.com/as5145 revision 1.17 33 - 36 as5145 datasheet - revision history revision history revision date owner description 1.1 may 30, 2008 apg changed the temperature to 150oc across the datasheet. jul 23, 2008 added key feature: fully automotive qualified to aec-q100, grade 0 jul 25, 2008 changed the values in table 10 for 10-bit and 12-bit incremental mode 1.2 aug 24, 2008 rfu inserted 10k for pin 6 in table 1 changed values for fmag_abs in table 4 made changes to incremental mode on page 14 . removed quadrature from figure 6 . inserted incremental output hysteresis on page 15 and figure . modified the typ value of all in table 11 . changed the values in equation2 (page 18) 1.3 aug 27, 2008 rfu modified applications removed table magnetic field strength variation indicator and modified table 9 cell headings 1.4 sep 29, 2008 apg changed angle position values in pulse width modulation (pwm) output on page 17 and also update table 6 for the same. feb 13, 2009 changed the value of t dovalid in table 6 feb 16, 2009 changed the value of pw min, pw max in table 6 updated figure 14 with 2.2f capacitor without polarity updated figure 17 with 2.2f instead of 2.2f....10f feb 18, 2009 mub changed key feature: added pre-programmed versions available removed 10 bit from pin descriptions for pin 12 on page 4 deleted min value for t dovalid in table 6 updated ordering information feb 22, 2009 apg changed the max value of t dovalid in table 6 to 413 1.5 jul 15, 2009 rfu added ?as5145-i10/as5145-i12? to the header made some sentence corrections and spelling mistakes 1.6 updated incremental mode on page 14 with new information. 1.7 aug 12, 2009 apg added a note to the ordering information 1.8 sep 29, 2009 rfu updated figure 13 added incremental power-up lock option on page 15 1.9 nov 05, 2009 apg timing characteristics (page 11) - updated the parameter ?pwm frequency? (f pwm ) 1.10 dec 04, 2009 updated section internal timing tolerance (page 29) 1.11 jun 16, 2010 mub updated table 1 , table 3 , table 6 jun 25, 2010 apg updated device header and ordering information (page 35) 1.12 nov 09, 2011 ach updated maximum rotation speed in incremental mode (see page 28) 1.13 nov 25, 2011 ekno updated msl in absolute maximum ratings and package drawings and markings . 1.14 feb 29, 2012 updated figure 23 and carried out sentence structure related changes across datasheet.
www.ams.com/as5145 revision 1.17 34 - 36 as5145 datasheet - revision history 1.15 jul 23, 2012 mub added comparison table (page 29), updated storage temp. values. 1.16 oct 16, 2012 updated table 5 and ams logos. 1.17 jul 04, 2013 ordering version tube removed. figure 4 replaced by new picture. revision date owner description
www.ams.com/as5145 revision 1.17 35 - 36 as5145 datasheet - ordering information 11 ordering information the devices are available as the standard products shown in table 16 . note: all products are rohs compliant and ams green. buy our products or get free samples online at www.ams.com/icdirect technical support is available at www.ams.com/technical-support for further information and requests, email us at sales@ams.com (or) find your local distributor at www.ams.com/distributor table 16. ordering information ordering code description delivery form package AS5145H-hsst 12-bit programmable magnetic rotary encoder tape & reel ssop 16 (5.3mm x 6.2mm) as5145a-hsst pre-programmed 10-bit incremental tape & reel as5145b-hsst pre-programmed 12-bit incremental tape & reel
www.ams.com/as5145 revision 1.17 36 - 36 as5145 datasheet - copyrights copyrights copyright ? 1997-2013, ams ag, tobelbaderstrasse 30, 8141 unterpremstaetten, austria-europe. trademarks registered ?. all right s reserved. the material herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written con sent of the copyright owner. all products and companies mentioned are trademarks or registered trademarks of their respective companies. disclaimer devices sold by ams ag are covered by the warranty and patent indemnification provisions appearing in its term of sale. ams ag makes no warranty, express, statutory, implied, or by description rega rding the information set forth herein or regarding the freedom of the described devices from patent infringement. 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 normal commercial applications. applications requiring extended temperature range, unusual environmental requirements, or high reliabi lity applications, such as military, medical life-support or life-sustaining equipment are specifically not recommended without addi tional processing by ams ag for each application. for shipments of less than 100 parts the manufacturing flow might show deviations from the stan dard production flow, such as test flow or test location. the information furnished here by ams ag is believed to be correct and accurate. however, 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, interruptio n of business or indirect, special, incidental or consequential damages, of any kind, in connection with or arising out of the furnishing, perfo rmance 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. contact information headquarters ams ag tobelbaderstrasse 30 a-8141 unterpremstaetten, austria tel : +43 (0) 3136 500 0 fax : +43 (0) 3136 525 01 for sales offices, distributors and representatives, please visit: http://www.ams.com/contact

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