AS5245 - austriamicrosystems AG - searchdatasheet.com

AS5245

Programmable 360º Magnetic Angle Encoder with Absolute SSI and

PWM Output

www.austriamicrosystems.com/AS5245 Revision 1.3 1 - 33

Data Sheet

1 General Description

The AS5245 is a contactless magnetic angle encoder for accurate

measurement up to 360º and includes two AS5145 devices in a

punched stacked leadframe.

It is a system-on-chip, combining inte grate d Hall element s, anal og

front end and digital signal processing in a single device.

To measure the angle, only a simple two-pole magnet, rotating over

the center of the chip is required. The magnet may be placed above

or below the IC.

The absolute angle measurement provides instant indication of the

magnet’s angular position with a resolution of 0.0879º = 4096

positions per revolution. This digital data is available as a serial bit

stream and as a PWM signal.

An internal voltage regulator allows operation of the AS5245 from

3.3V or 5.0V supplies.

The AS5245 is fully automotive qualified to AEC-Q100, grade 0.

2 Key Features

 Contactless high resolution rotational position encoding over a

full turn of 360º

 Two digital 12-bit absolute outputs

 Quadrature A/B (10- or 12-bit) and Index output signal

 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

 Tolerant to magnet misalignment and air gap variations

 Wide temperature range: - 40ºC to +150ºC

 Unique Chip Identifier

 Fully automotive qualified to AEC-Q100, grade 0

 Small package: QFN 32 LD (7x7)

3 Applications

The AS5245 is ideal for applications with an angular travel range

from a few degrees up to a full turn of 360º. The device is suitable for

Automotive applications like Throttle position sensors, Gas/brake

pedal position sensing, Headlight position control, Contactless rotary

position sensing, Front panel rotary switches and Replacement of

potentiometer.

DSP

Hall Array

Frontend

Amplifier

Absolute

Interface

(SSI)

Incremental

Interface

Sin

Cos

Ang

Mag

MagINCn

MagDECn

PWM

CLK

DTEST1_A

DTEST2_B

Mode_Index

PDIO

CSn

PWM

Interface

OTP

VDD5V

VDD3V3

LDO 3.3V

Mux AS5245

Note: This Block Diagram presents only one die

Figure 1. AS5245 Block Diagram

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AS5245
Data Sheet - C o n t e nt s
Contents
General Description.................................................................................................................................................................. 1
Key Features............................................................................................................................................................................. 1
Applications............................................................................................................................................................................... 1
Pin Assignments....................................................................................................................................................................... 4
1  Pin Descriptions.................................................................................................................................................................................... 5
Absolute Maximum Ratings...................................................................................................................................................... 6
Electrical Characteristics........................................................................................................................................................... 7
1  Magnetic Input Specification................................................................................................................................................................. 8
2  System Specifications .......................................................................................................................................................................... 9
Timing Characteristics............................................................................................................................................................ 11
Detailed Description................................................................................................................................................................ 12
1  Mode_Index Pin.................................................................................................................................................................................. 12
2  Synchronous Serial Interface (SSI).................................................................................................................................................... 13
2.1  Serial Data Contents.................................................................................................................................................................. 13
2.2  Z-axis Range Indication (Push Button Feature, Red/Yellow/Green Indicator)........................................................................... 14
2.3  Incremental Mode.................................................. ....... ...... ................................. ...................................................................... 14
2.4  Sync Mode.......................................... ...... ................................. ................................................................................................ 16
2.5  Sine/Cosine Mode ....................... ....... ...... ....... ................................ .......................................................................................... 16
2.6  Daisy Chain Mode ..................................................................................................................................................................... 16
3  Pulse Width Modulation (PWM) Output.............................................................................................................................................. 17
3.1  Changing the PWM Frequency.... ....... ...... ................................. ................................ ................................................................ 18
4  Analog Output..................................................................................................................................................................................... 18
Application Information........................................................................................................................................................... 19
1  Programming the AS5245.................................................................................................................................................................. 19
1.1  Zero Position Programming....................................................................................................................................................... 19
1.2  OTP Memory Assignment.......................................................................................................................................................... 20
1.3  User Selectable Settings ........................................................................................................................................................... 20
1.4  OTP Default Setting................................................................................................................................................................... 21
1.5  Redundancy.................... ................................. .......................................................................................................................... 21
1.6  Redundant Programming Option............................................................................................................................................... 21
2  Alignment Mode.................................................................................................................................................................................. 22
3  3.3V / 5V Operation............................................................................................................................................................................ 23
4  Choosing the Proper Magnet.............................................................................................................................................................. 24
5  Failure Diagnostics............................................................................................................................................................................. 25
5.1  Magnetic Field Strength Diagnosis............................................................................................................................................ 25
5.2  Power Supply Failure Detection ................................................................................................................................................ 25
6  Angular Output Tolerances................................................................................................................................................................. 25
6.1  Accuracy................................ ................................ ....... ................................ ............................................................................. 25
6.2  Transition Noise......................................................................................................................................................................... 27
6.3  High Speed Operation............................................................................................................................................................... 27
6.4  Propagation Delays ...................................................... ................................ ............................................................................. 28
6.5  Internal Timing Tolerance................... ................................ ................................. ...................................................................... 28
6.6  Temperature............. ...... ................................. ...... ................................. ................................................................................... 28
6.7  Accuracy over Temperature...................................................................................................................................................... 28
7  AS5245 Differences to AS5045.......................................................................................................................................................... 29

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AS5245

Data Sheet - C o n t e nt s

10 Package Drawings and Markings......................................................................................................................................... 30

11 Ordering Information............................................................................................................................................................. 32

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AS5245

Data Sheet - P i n As s i g n m e nt s

4 Pin Assignments

Figure 2. Pin Assignments (Top Vie w)

AS5245

252627282930

161514131211

3132

109

VSS_Bottom

PDIO_Top

PDIO_Bottom

CLK_Top

CLK_Bottom

DO_Top

DO_Bottom

CSn_Bottom

VDD3V_Bottom

PWM_Top

PWM_Bottom

CSn_Top

DTest1_A_Top

MagDECn_Bottom

MagDECn_Top

MagINCn_Bottom

MagINCn_Top

VDDA5V_Top

VDDA5V_Bottom

VDD3V_Top

DTest1_A_Bottom

DTest2_B_Top

DTest2_B_Bottom

Mode_Index_Top

Mode_Index_Bottom

VSS_Top

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AS5245

Data Sheet - P i n As s i g n m e nt s

4.1 Pin Descriptions

Table 1. Pin Descriptions

Pin Name Pin Number Pin Type Description

DTest1_A 1, 32 Digital output Test output in default mode

DTest2_B 2, 3 Digital output Test output in default mode

NC 4, 5 - For internal use. Must be left unconnected

Mode_Index 6, 7 Digital I/O pull-down Select between slow (open, low: VSS) and fast (high) mode. Internal pull-

down resistor.

VSS 8, 9 Supply pin Negative Supply Voltage (GND)

PDIO 10, 11 Digital input pull-down OTP Programming Input and Data Input for Daisy Chain mode.

Internal pull-down resistor (~74kΩ). Should be connected to VSS if

programming is not used.

CLK 12, 13 Digital input, Schmitt-

trigger input Clock Input of Synchronous Serial Interface; Schmitt-Trigger input

DO 14, 15 Digital output / tri-

state Data Output of Synchronous Serial Interface

CSn 16, 17 Digital input pull-up,

Schmitt-trigger input Chip Select. Active low. Schmitt-Trigger input, internal pull-up resistor

(~50kΩ)

PWM 18, 19 Digital output Pulse Width Modulation of approx. 244Hz; 1µs/step (opt. 122Hz; 2µs/

step)

NC 20, 21 - For internal use. Must be left unconnected

NC 22, 23 - For internal use. Must be left unconnected

VDD3V3 24, 25 Supply pin 3V-Regulator Output for internal core, regulated from VDD5V. Connect to

VDD5V for 3V supply voltage. Do not load externally.

VDD5V 26, 27 Supply pin Positive Supply Voltage, 3.0V to 5.5V

MagINCn 28, 29 Digital output open

drain Magnet Field Magnitude Increase. Active low. Indicates a distance

reduction between the magnet and the device surface.

MagDECn 30, 31 Digital output open

drain Magnet Field Magnitude Decrease. Active low. Indicates a distance

increase between the device and the magnet.

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AS5245

Data Sheet - A b s o lu t e M a x im u m R a t i n gs

5 Absolute Maximum Ratings

Stresses beyond those list ed 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 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

DC supply voltage at pin VDD5V -0.3 7 V

DC supply voltage at pin VDD3V3 -0.3 5 V

Input pin voltage -0.3 7 V Pins Prog, MagINCn, MagDECn, CLK, CSn

Input current (latchup immunity) -100 100 mA Norm: JEDEC 78

Electrostatic discharge ±2 kV Norm: MIL 883 E method 3015

Storage temperature -55 +150 ºC

Body temperature (Lead-free package) 260 ºC t=20 to 40s, Norm: IPC/JEDEC J-Std-020C

Lead finish 100% Sn “matte tin”

Humidity non-condensing 5 85 %

Ambient temperature -40 150 ºC

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AS5245

Data Sheet - E l e c tr i c a l C h ar a c t e r i s t ic s

6 Electrical Characteristics

TAMB = -40 to +150ºC, VDD5V = 3.0-3.6V (3V operation) VDD5V = 4.5-5.5V (5V operation) unless otherwise noted.

Table 3. Electrical Characteristics

Symbol Parameter Condition Min Typ Max Unit

Operating Conditions

TAMB Ambient temperature -40 +150 ºC

Isupp Supply current (one die only) 16 21 mA

VDD5V Supply voltage at pin VDD5V 5V Operation 4.5 5.0 5.5 V

VDD3V3 V oltage regulator output voltage at pin

VDD3V3 3.0 3.3 3.6

VDD5V Supply voltage at pin VDD5V 3.3V Operation

(pin VDD5V and VDD3V3 connected) 3.0 3.3 3.6 V

VDD3V3 Supply voltage at pin VDD3V3 3.0 3.3 3.6

VON Power-on reset thresholds

On voltage; 300mV typ. hysteresis DC supply voltage 3.3V (VDD3V3) 1.37 2.2 2.9 V

VOFF Power-on reset thresholds

Off voltage; 300mV typ. hysteresis 1.08 1.9 2.6

Programming Conditions

VPROG Programming voltage Voltage applied during programming 3.3 3.6 V

VProgOff Programming voltage off level Line must be discharged to this level 0 1 V

IPROG Programming current Current during programming 100 mA

Rprogrammed Programmed fuse resistance (log 1) 10µA maximum current@100mV 100k ∞Ω

Runprogrammed Unprogrammed fuse resistance (log

0) 2mA maximum current@100mV 50 100 Ω

DC Characteristics CMOS Schmitt-Trigger Inputs: CLK, CSn (CSn = Internal Pull-up)

VIH High level input voltage Normal operation 0.7 *

VDD5V V

VIL Low level input voltage 0.3 *

VDD5V V

VIon- VIoff Schmitt Trigger hysteresis 1 V

ILEAK Input leakage current CLK only -1 1 µA

IiL Pull-up low level input current CSn only, VDD5V: 5.0V -30 -100

DC Characteristics CMOS / Program Input: PDIO

VIH High level input voltage 0.7 *

VDD5V VDD5V V

VPROG High level input voltage During programming,

Either with 3.3V or 5V supply 3.3 3.6 V

VIL Low level input voltage 0.3 *

VDD5V V

IiL High level input current VDD5V: 5.5V 30 100 µA

DC Characteristics CMOS Output Open Drain: MagINCn, MagDECn

IOZ Open drain leakage current 1 µA

VOL Low level output voltage VSS

+0.4 V

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AS5245

Data Sheet - E l e c tr i c a l C h ar a c t e r i s t ic s

6.1 Magnetic Input Specification

TAMB = -40 to +150ºC, VDD5V = 3.0 to 3.6V (3V operation) VDD5V = 4.5 to 5.5V (5V operation) unless otherwise noted.

Two-pole cylindrical diametrically magnetized source:

IOOutput current VDD5V: 4.5V 4 mA

VDD5V: 3V 2

DC Characteristics CMOS Output: PWM

VOH High level output voltage VDD5V–

0.5 V

VOL Low level output voltage VSS

+0.4 V

IOOutput current VDD5V: 4.5V 4 mA

VDD5V: 3V 2

DC Characteristics CMOS Output: A, B, Index

VOH High level output voltage VDD5V–

0.5 V

VOL Low level output voltage VSS

+0.4 V

IOOutput current VDD5V: 4.5V 4 mA

VDD5V: 3V 2

DC Characteristics Tri-state CMOS Output: DO

VOH High level output voltage VDD5V–

0.5 V

VOL Low level output voltage VSS

+0.4 V

IOOutput current VDD5V: 4.5V 4 mA

VDD5V: 3V 2

IOZ Tri-state leakage current 1 µA

Table 4. Magnetic Input Specification

Symbol Parameter Condition Min Typ Max Unit

dmag Diameter Recommended magnet: Ø 6mm x 2.5mm for

cylindrical magnets 46 mm

tmag Thickness 2.5 mm

Bpk Magnetic input field amplitude Required vertical component of the magnetic

field strength on the die’s surface, measured

along a concentric circle with a radius of

1.1mm 45 75 mT

Boff Magnetic offset Constant magnetic stray field ± 10 mT

Field non-linearity Including offset gradient 5 %

fmag_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

Disp Displacement radius Maximum offset between defined device

center and magnet axis 0.25 mm

Ecc Eccentricity Eccentricity of magnet center to rotational axis 100 µm

Table 3. Electrical Characteristics

Symbol Parameter Condition Min Typ Max Unit

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AS5245

Data Sheet - E l e c tr i c a l C h ar a c t e r i s t ic s

6.2 System Specifications

TAMB = -40 to +150ºC, VDD5V = 3.0 to3.6V (3V operation) VDD5V = 4.5 to5.5V (5V operation) unless otherwise noted.

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

INLopt Integral non-linearity (optimum) Maximum error with respect to the best line fit.

Centered magnet without calibration, TAMB

=25ºC. ±0.5 deg

INLtemp Integral non-linearity (optimum) Maximum error with respect to the best line fit.

Centered magnet without calibration,

TAMB = -40 to +150ºC±0.9 deg

INL Integral non-linearity Best line fit = (Errmax – Errmin) / 2

Over displacement tolerance with 6mm

diameter magnet, without calibration, T AMB = -

40 to +150ºC ±1.4 deg

DNL Differential non-linearity 12bit, 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

tPwrUp Power-up time

Fast mode (Mode = 1);

Until status bit OCF = 1 20 ms

Slow mode (Mode = 0 or open);

Until OCF = 1 80

tdelay System propagation delay

absolute output : delay of ADC, DSP

and absolute interface

Fast mode (MODE = 1) 96 µs

Slow mode (MODE = 0 or open) 384

fSInternal sampling rate for absolute

output:

TAMB = 25ºC, slow mode

(MODE=0 or open) 2.48 2.61 2.74 kHz

TAMB = -40 to +150ºC, slow mode (MODE=0

or open) 2.35 2.61 2.87

fSInternal sampling rate for absolute

output

TAMB = 25ºC, fast mode

(MODE = 1) 9.90 10.42 10.94 kHz

TAMB = -40 to +150ºC, fast mode

(MODE=1) 9.38 10.42 11.46

CLK/SEL Read-out frequency Maximum clock frequency to read out serial

data 1MHz

Table 4. Magnetic Input Specification

Symbol Parameter Condition Min Typ Max Unit

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AS5245

Data Sheet - E l e c tr i c a l C h ar a c t e r i s t ic s

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

512

1023

10bit code

0.35°INL

Ideal curve

Actual curve

512

1023

DNL+1LSB

[degrees]

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AS5245

Data Sheet - T i m i n g C h a r a c t e r i st i c s

7 Ti ming Characteristics

TAMB= -40 to +150ºC, VDD5V= 3.0 to 3.6V (3V operation) VDD5V= 4.5 to 5.5V (5V operation), unless otherwise noted.

Table 6. Timing Characteristics

Symbol Parameter Conditions Min Typ Max Units

Synchronous Serial Interface (SSI)

tDOactive Data output activated (logic high) Time between falling edge of CSn and

data output activated 100 ns

tCLKFE First data shifted to output register Time between falling edge of CSn and

first falling edge of CLK 500 ns

TCLK/2 Start of data output Rising edge of CLK shifts out one bit at a

time 500 ns

tDOvalid Data output valid Time between rising edge of CLK and

data output valid 413 ns

tDOtristate Data output tri-state After the last bit DO changes back to “tri-

state” 100 ns

tCSn Pulse width of CSn CSn =hi gh; To initiate read-out of next

angular position 500 ns

fCLK Read-out frequency Clock frequency to read out serial data >0 1 MHz

Pulse Width Modulation Output

fPWM PWM frequency Signal period = 4098µs ±10% at TAMB

= -40 to +150ºC 220 224 268 Hz

PWMIN Minimum pulse width Position 0d; angle 0 degree 0.90 1 1.10 µs

PWMAX Maximum pulse width Position 4098d; angle 359.91 degrees 3686 4096 4506 µs

Programming Conditions

tPROG Programming time per bit Time to prog. a singe fuse bit 10 20 µs

tCHARGE Refresh time per bit Time to charge the cap after tPROG 1µs

fLOAD LOAD frequency Data can be loaded at n x 2µs 500 kHz

fREAD READ frequency Read the data from the latch 2.5 MHz

fWRITE WRITE frequency Write the data to the latch 2.5 MHz

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AS5245

Data Sheet - D e t a il e d D e s c ri p t i o n

8 Detailed Description

The AS5245 is manufactured in a CMOS standard process and uses a spinning current Hall technology for sensing the magnetic field

distribution across the surface of the chip. The integrated Hall elements are placed around the center of the device and deliver a voltage

representation of the magnetic field at the surface of the IC.

Through Sigma-Delta Analog / Digital Conversion and Digital Signal-Processing (DSP) algorithms, the AS5245 provides accurate high-resolution

absolute angular position information. For this purpose, a Coordinate Rotation Digital Computer (CORDIC) calculates the angle and the

magnitude of the Hall array signals. The DSP is also used to provide digital information at the outputs MagINCn and MagDECn that indi cat e

movements of the used magnet towards or away from the device’s surface. A small low cost diametrically magnetized (two-pole) standard

magnet provides the angular position information (see Figure 16).

The AS5245 senses the orientation of the magnetic field and calculates a 12-bit binary code. This code can be accessed via. a Synchronous

Serial Interface (SSI). In addition, an absolute angular representation is given by a Pulse Width Modulated signal at pin 12 (PWM). This PWM

signal output also allows the generation of a direct proportional analog voltage, by using an external Low-Pass-Filter. The AS5245 is tolerant to

magnet misalignment and magnetic stray fields due to differential measurement technique and Hall sensor conditioning circuitry.

Figure 4. Typical Arrangement of AS5245 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 384µs. This mode is

recommended for high precision, low speed applications.

Deactivating the filter (Mode pin = HIGH) reduces the output delay to 96µs and provides an output noise of 0.06º rms. This mode is

recommended for higher speed applications.

Setting up 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, VDD=5V)

Sampling rate 2.61 kHz (384 µs) 10.42 kHz (96µs)

Tr ansition noise (1 sigma) ≤ 0.03º rms ≤ 0.06º rms

Output delay 384µs 96µs

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

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AS5245

Data Sheet - D e t a il e d D e s c ri p t i o n

8.2 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 initiated.

 After a minimum time tCLK FE, data is latched into the output shift register with the first falling edge of CLK.

 Each subsequent rising CLK edge shifts out one bit of data.

 The serial word contains 18 bits, the first 12 bits are the angular information D[11:0], the subsequent 6 bits contain system information,

about the validity of data such as OCF, COF, LIN, Parity and Magnetic Field status (increase/decrease).

 A subsequent measurement is initiated by a “high” pulse at CSn with a minimum duration of tCSn.

8.2.1 Serial Data Contents

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 D9:D0 is invalid. The

absolute output maintains the last valid angular value. This alarm may be resolved by bringing the magnet within the X-Y-Z tolerance limits.

LIN – (Linearity Alarm). Logic high indicates that the input field generates a critical output linearity. When this bit is set, the data at D9:D 0 may sti ll

be used, but can contain invalid data. This warning may be resolved by bringing 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

100

Even checksum of bits

1:15

CSn

CLK

tDO valid

Angular Position Data

tDO active Status Bits tDO Tristate

tCSn

tCLKFE

tCLKFE TCLK/2

D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 OCF COF LIN Mag

INC Mag

DEC Even

PAR

818

D11D10

D11

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AS5245

Data Sheet - D e t a il e d D e s c ri p t i o n

8.2.2 Z-axis Range Indication (Push Button Feature, Red/Yellow/Green Indicator)

The AS5245 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 pins (pins #1 and 2) and as status bits in the serial data stream (see Figure 5). Additionally, an OTP

programming option is available with bit MagCompEn that enables additional features:

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 magnetic

field is in range, both outputs are turned off.

The two pins may also be combined with a single pull-up resistor. In this case, the signal is high when the magnetic field is in range. It is low in all

other cases (see Table 9).

8.2.3 Incremental Mode

The AS5245 has an internal interpolator block. This function is used if the input magnetic field is too 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 versions (10bit

and 12bit), these bits are set during test at austriamicrosystems. 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 recommended.

During operation in incremental mode it is recommended setting CSn = High, to disable the SSI-Interface.

Table 9. Magnetic Field Strength Red-Yellow-Green Indicator (OTP option)

Status Bits Hardware Pins OPT: Mag CompEn = 1 (Red-Yellow-Green Programming Option)

Mag

INC Mag

DEC LIN Mag

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 AS5245

may 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 AS5245 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

AS5245 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).

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

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AS5245

Data Sheet - D e t a il e d D e s c ri p t i o n

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 degrees 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 accordingly. A change of the

magnet’s rotational direction back to position “x+3“ means that the incremental output still remains unchanged for the duration of 4 LSB, until

position “x+2“is reached. Following this direction, the incremental outputs will again be updated with every change of the magnet position.

Figure 7. Hysteresis Window for Incremental Outputs

Mode_Index

D Test2_B

D Test1_A

1 LSB

Programmed

Zero Position

ClockWise

3 LSB

Counter ClockWise

Ma gnet Pos ition

Hysteresis :

0.35°

X +2

Incremental

Output

Indication

Clockwise Direction

Counter c lock wis e Dir ec tion

X +4

XX X +2 X +4 X +5X +3X +1

X +1

X +3

X +6

X +5

X +6

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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 interpolator 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.

8.2.4 Sync Mode

This mode is used to synchronize the external electronic with the AS5245. In this mode, two signals are provided at the pins DTEST1_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.

8.2.5 Sine/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 digital 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 externally. 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 indicates, which phase of signal is being presented. The mode is not available in

the default mode.

8.2.6 Daisy Chain Mode

The Daisy Chain mode allows connection of several AS5245s in series, while still keeping just one digital input for data transfer (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 stream 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), etc. (see Figure 10).

Figure 9. Daisy Chain Hardware Configuration

DTest1_A

DTest1_B

400µs (100µs)

CSn

CSn CSn CSn

CLK CLK CLK

CLK

Data IN

AS5145

1st Device

AS5145

2nd Device AS5145

last Device

µC

DO DO DO

PDIO PDIO PDIO

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Figure 10. Daisy Chain Mode Data Transfer

8.3 Pulse Width Modulation (PWM) Output

The AS5245 provides a pulse width modulated output (PWM), whose duty cycle is proportional to the measured angle. For angle posit ion 0 to

4094:

Position = (EQ 1)

Examples:

1. An angle position of 180º will generate a pulse width ton = 2049µs and a pause tOFF of 2049 µs resulting in Position = 2048 after the

calculation: 2049 * 4098 / (2049 + 2049) -1 = 2048

2. An angle position of 359.8º will generate a pulse width ton = 4095µs and a pause tOFF of 3 µs resulting in Position = 4094 after the cal-

culation: 4095 * 4098 / (4095 + 3) -1 = 4094

Exception:

1. An angle position of 359.9º will generate a pulse width ton = 4097µs and a pause tOFF of 1 µs 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 cancelled by

measuring the complete duty cycle as shown above.

Figure 11. PWM Output Signal

CSn

CLK

tDO valid

Angular Position Data

tDO active Status Bits

tCLK FE TCLK/2

D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 OCF COF LIN Mag

INC Mag

DEC Even

PAR

818 D

D11

123

D10 D9

Angular Position Data

1st Device 2nd Device

D10

D11

ton 4098⋅

ton toff

+()

------------------------- 1–

4097µs

4096µs

1/fPWM

PWMAX

PWMIN

359.91 deg

(Pos 4095)

0 deg

(Pos 0)

Angle

1µs

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8.3.1 Changing the PWM Frequency

The PWM frequency of the AS5245 can be divided by two by setting a bit (PWMhalfEN) in the OTP register (see Programming the AS5245 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:

8.4 Analog Output

An analog output can be generated by averaging the PWM signal, using an external active or passive low pass filter. The analog output voltage

is proportional to the angle: 0º= 0V; 360º = VDD5V.

Using this method, the AS5245 can be used as direct replacement of potentiometers.

Figure 12. Simple 2nd Order Passive RC Low Pass Filter

Figure 12 shows an example of a simple passive low pass filter to generate the analog output.

R1,R2

≥

4k7 C1,C2

≥

1µF / 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 filtering and less

ripple, but will also slow down the response time.

Table 11. PWM Signal Parameters (default mode)

Symbol Parameter Typ Unit Note

fPWM PWM frequency 244 Hz Signal period: 4097µs

PWMIN MIN pulse width 1 µs - Position 0d

- Angle 0 deg

PWMAX MAX pulse width 4096 µs - Position 4095d

- Angle 359,91 deg

Table 12. PWM Signal Parameters with Half Frequency (OTP option)

Symbol Parameter Typ Unit Note

fPWM PWM frequency 2 µs - Position 0d

- Angle 0 deg

PWMIN MIN pulse width 8192 µs - Position 4095d

- Angle 359,91 deg

PWMAX MAX pulse width 2 µs - Position 0d

- Angle 0 deg

R1 R2 analog out

Pin12

PWM

Pin7

VSS

C1 C2 VDD

0V 0º 360º

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Data Sheet - A p p li c a t i o n I n fo r m a t i o n

9 Application Information

The benefits of AS5245 are as follows:

 Complete system -on-chip

 Angle measurement with programmable range up to 360º

 High reliability due to non-contact magnetic sensing

 Ideal for applications in harsh environments

 Robust system, tolerant to magnet misalignment, airgap variations, temperature variations and external magnetic fields

 No calibration required

 Building of redundancy systems with plausibility checks

9.1 Programming the AS5245

After power-on, programming the AS5245 is enabled with the rising edge of CSn with PDIO = high and CLK = low.

The AS5245 programming is a one-time programming (OTP) method, based on poly silicon fuses. The advantage of this method is that a

programming voltage of only 3.3V to 3.6V is required for programming.

The OTP consists of 52 bits, of which 21 bits are available for user programming. The remaining 31 bits contain factory settings and a unique

chip identifier (Chip-ID).

A single OTP cell can be programmed only once. Per default, the cell is “0”; a programmed cell will contain a “1”. While it is not possible to reset

a programmed bit from “1” to “0”, multiple OTP writes are possible, as long as only unprogrammed “0”-bits are programmed to “1”.

Independent of the OTP programming, it is possible to overwrite the OTP register temporarily with an OTP write command at any time. This

setting will be cleared and overwritten with the hard programmed OTP settings at each power-up sequence or by a LOAD operation. 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

programmed or unprogrammed bit, there is a representative analog value (in essence, a resistor value) that is read to verify whether a bit

has been successfully programmed or not.

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 adjusted to the

mechanical zero position. Once the assembly is completed, the mechanical and electrical zero positions can be matched by software. Any

position within a full turn can be defined as the permanent new zero 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.

Note: The zero position value may 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 into the

OTP register.

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9.1.2 OTP Memory Assignment

9.1.3 User Selectable Settings

The AS5245 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.

-MagCompEN: The green/yellow mode can be enabled by setting of this bit.

-Output Md0: Setting this bit enables sync- or 10bit incremental mode (see Table 10)

-Output Md1: Setting this bit enables sync- or 12bit incremental mode (see Table 10)

-Z [11:0]: Programmable Zero / Index Position

-CCW: Counter Clockw ise 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 origi-

nal OTP bit setting

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

49 pwmDIS Disable PWM

48 Output Md0 Default, 10 bit inc, 12 bit inc

47 Output Md1 Sync mode

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 9

17 ChipID0

18 bit Chip ID

ID Section

16 ChipID1

0ChipID17

mbit0 Factory Bit 0

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9.1.4 OTP Default Setting

The AS5245 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. This function can be used in cases where the programming of one bit fails.

With an address RA(4:0), one bit can be selected and programmed.

9.1.6 Redundan t 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.

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

0000000000000000000000 0

00001 10000000000000000 0

00010 0 1000000000000000 0

00011 0 0 100000000000000 0

00100 0 0 0 10000000000000 0

0010100001000000000000 0

0011000000100000000000 0

0011100000010000000000 0

0100000000001000000000 0

0100100000000100000000 0

0101000000000010000000 0

0101100000000001000000 0

0110000000000000100000 0

0110100000000000010000 0

0111000000000000001000 0

0111100000000000000100 0

10000000000000000000100

10001000000000000000010

1001000000000000000000 1

10101 11111111111111111 1

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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 13 ). 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 field strength. The

magnet is properly aligned, when the difference between highest and lowest value over one full turn is at a minimum.

Under normal conditions, a properly aligned magnet will result in a reading of less than 128 over a full turn.

The MagINCn and MagDECn indicators will be = 1 when the alignment mode reading is < 128. At the same time, both hardware pins MagINCn

(#1) and MagDECn (#2) will be pulled to VSS. A properly aligned magnet will therefore produce a MagINCn = MagDECn = 1 signal throughout a

full 360º turn of the magnet.

Stronger magnets or short gaps between magnet and IC may show values larger than 128. These magnets are still properly aligned as long as

the difference between highest and lowest value over one full turn is at a minimum.

The Alignment mode can be reset to normal operation by a power-on-reset (disconnect / re-connect power supply) or by a falling edge on CSn

with PDIO = low.

Figure 13. Enabling the Alignment Mode

Figure 14. Exiting Alignment Mode

PDIO

CSn AlignMode enable Read-out

via SSI

2µs

min. 2µs

min.

PDIO

CSn exit AlignMode Read-out

via SSI

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9.3 3.3V / 5V Operation

The AS5245 operates either at 3.3V ±10% or at 5V ±10%. This is made possible by an internal 3.3V Low-Dropout (LDO) V oltage regulator. The

internal supply voltage is always taken from the output of the LDO, meaning that the internal blocks are always operating at 3.3V.

For 3.3V operation, the LDO must be bypassed by connecting VDD3V3 with VDD5V (see Figure 15).

For 5V operation, the 5V supply is connected to pin VDD5V, while VDD3V3 (LDO output) must be buffered by a 1...10µF capacitor, which is

supposed to be placed close to the supply pin (see Figure 15).

Note: The VDD3V3 output is intended for internal use only. It must not be loaded with an external load.

The output voltage of the digital interface I/O’s corresponds to the voltage at pin VDD5V, as the I/O buffers are supplied from this pin.

Figure 15. Connections for 5V / 3.3V Supply Voltages

A buffer capacitor of 100nF is recommended in both cases close to pin VDD5V. Note that pin VDD3V3 must always be buffered by a capacitor . It

must not be left floating, as this may cause an instable internal 3.3V supply voltage, which may lead to larger than normal jitter of the measured

angle.

Internal

VDD

LDO

VSS

VDD5V

VDD3V3

100n

4.5 - 5.5V

1... 10µF

PWM

CLK

CSn

PDIO

Internal

VDD

LDO

VSS

VDD5V

VDD3V3

3.0 - 3.6V

PWM

CLK

CSn

PDIO

100n

5V Operation 3.3V Operation

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9.4 Choosing the Proper Magnet

Typically, the magnet should be 6mm in diameter and ≥ 2.5mm in height. Magnetic materials such as rare earth AlNiCo/SmCo5 or NdFeB are

recommended. The magnetic field strength perpendicular to the die surface has to be in the range of ±45mT…±75mT (peak).

The magnet’s field strength should be verified using a gauss-meter. The magnetic field Bv at a given distance, along a concentric circle with a

radius of 1.1mm (R1), should be in the range of ±45mT…±75mT (see Figure 16).

Figure 16. Typical Magnet (6x3mm) and Magnetic Field Distribution

Magnet axis

Vertical field

component

(45…75mT)

360

Vertical field

component

R1 concentric circle;

radius 1.1mm

Magnet axis

typ. 6mm diameter

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9.5 Failure Diagnostics

The AS5245 also offers several diagnostic and failure detection features, which are discussed in detail further in the document.

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 (MagINCn) or away from

the chip (MagDECn).

9.5.2 Power Supply Failure Detection

By Software: If the power supply to the AS5245 is interrupted, the digital data read by the SSI will be all “0”s. Data is only valid, when bit OCF is

high, hence a data stream with all “0”s is invalid. To ensure adequate low levels in the failure case, a pull-down resistor (~10kΩ) should be added

between pin 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 AS5245, the pull-up resistors

(~10kΩ) from each pin must be connected to the positive supply at pin 16 (VDD5V).

By Hardware, PWM Output: The PWM output is a constant stream of pulses with 1kHz repetition frequency . In case of power loss, these pulses

are missing.

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 19).

Misalignment of the magnet further reduces the accuracy . Figure 18 shows an example of a 3D-graph displaying non-linearity over XY-

misalignment. The center of the square XY-area corresponds to a centered magnet (see dot in the center of the graph). The X- and Y- axis

extends to a misalignment of ±1mm in both directions. The total misalignment area of the graph covers a square of 2x2 mm (79x79mil) with a

step size of 100µm.

For each misalignment step, the measurement as shown in Figure 19 is repeated and the accuracy (Errmax – Errmin)/2 (e.g. 0.25º in Figure 19) is

entered as the Z-axis in the 3D-graph.

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Figure 17. 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. For volume

production, the placement tolerance of the IC within the package (±0.235mm) must also be taken into account. The total nonlinearity error over

process tolerances, temperature and a misalignment circle radius of 0.25mm is specified better than ±1.4 degrees. The magnet used for this

measurement was a cylindrical NdFeB (Bomatec® BMN-35H) magnet with 6mm diameter and 2.5mm in height.

-1000

-700

-400

-100

200

500

800

-1000

-800

-600

-400

-200

200

400

600

800

1000

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Figure 18. Example of Linearity Error Over 360º

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 transition noise at the

outputs. It is specified as 0.06 degrees rms (1 sigma)1 in fast mode (pin MODE = high) and 0.03 degrees rms (1 sigma) in slow 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

readings. An averaging of 4 readings will reduce the transition noise by 6dB or 50%, e.g. from 0.03º rms to 0.015º rms (1 sigma) in slow

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 side, the transition

noise may again be reduced by averaging of readings.

 Incremental Mode: In incremental mode, the transition noise influences the period, width and phase shift of the output signals A, B and

Index. However, the algorithm used to generate the incremental outputs guarantees no missing or additional pulses even at high speeds (up

to 30.000 rpm and higher).

9.6.3 High Speed Operation

Sampling Rate. The AS5245 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 384µs (96µs in fast mode). At a stationary position of the magnet,

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

calculated by,

nslowomode = (EQ 3)

nfastmode = (EQ 4)

The upper speed limit in slow mode is ~6.000rpm and ~30.000rpm 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.

1. Statistically, 1 sigma represents 68.27% of readings; 3 sigma represents 99.73% of readings.

-0.5

-0.4

-0.3

-0.2

-0.1

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

rpm 384()μs⋅

-----------------------------------

rmp 96μs⋅

---------------------------

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Incremental Mode. Incremental encoders are usually required to produce no missing pulses up to several thousand rpms. Therefore, the

AS5245 has a built-in interpolator, which ensures that there are no missing pulses at the incremental outputs for rotational speeds of up to

30.000 rpm, even at the highest resolution of 10 bits (512 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 data. This delay is

96µs in fast mode and 384µs in slow mode.

Using the SSI interface for absolute data transmission, an additional delay must be considered, caused by the asynchronous sampling (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: esampling = rpm * 6 * pr op.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 AS5245.

9.6.5 Internal Timing Tolerance

The AS5245 does not require an external ceramic resonator or quartz. All internal clock timings for the AS5245 are generated by an on-chip RC

oscillator. This oscillator is factory trimmed to ±5% accuracy at room temperature (±10% over full temperature range). This tolerance infl uen c es

the ADC sampling rate and the pulse width of the PWM output:

 Absolute Output; SSI Interface: A new angular value is updated every 96µs (typ) in fast mode and every 384µs (typ) in slow mode.

 PWM Output: A new angular value is updated every 400µs (typ). The PWM pulse timings tON and tOFF also have the same tolerance as

the internal oscillator. If only the PWM pulse width tON is used to measure the angle, the resulting value also has this timing tolerance.

However, this tolerance can be cancelled by measuring both tON and tOFF and calculating the angle from the duty cycle (see Pulse Width

Modulation (PWM) Output on page 17).

 Incremental Mode: In incremental mode, the transition noise influences the period, width and phase shift of the output signals A, B and

Index. However, the algorithm used to generate the incremental outputs guarantees no missing or additional pulses even at high speeds (up

to 30.000 rpm and higher).

Position = (EQ 6)

9.6.6 Temperature

Magnetic Temperature Coefficient. One of the major benefits of the AS5245 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 AS5245 automatically

compensates for the varying magnetic field strength over temperature. The magnet’s temperature drift does not need to be considered, as the

AS5245 operates with magnetic field strengths from ±45…±75mT.

Example:

A NdFeB magnet has a field strength of 75mT @ -40ºC and a temperature coefficient of -0.12% per Kelvin. The temperature change is from -40º

to +125º = 165K.The magnetic field change is: 165 x -0.12% = -19.8%, which corresponds to 75mT at -40ºC and 60mT at 125ºC.

The AS5245 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 temperature, it may

increase to less then or equal to ±0.9º due to increasing noise at high temperatures.

ton 4097⋅

ton toff

+()

------------------------- 1–

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AS5245

Data Sheet - A p p li c a t i o n I n fo r m a t i o n

Timing Tolerance over Temperature. The internal RC oscillator is factory trimmed to ±5%. Over temperature, this tolerance may increase

to ±10%. Generally, the timing tolerance has no influence in the accuracy or resolution of the system, as it is used mainly for internal clock

generation. The only concern to the user is the width of the PWM output pulse, which relates directly to the timing tolerance of the internal

oscillator. This influence, however, can be cancelled by measuring the complete PWM duty cycle instead of just the PWM pulse.

9.7 AS5245 Differences to AS5045

All parameters are according to AS5045 data sheet except for the parameters shown below:

Table 15. Difference Between AS5245 and AS5045

Building Block AS5245 AS5045

Resolution 12bits, 0.088º/step. 12bits, 0.088º/step.

Ambient temperature range -40ºC to +150ºC -40ºC to +125ºC

Data length

read: 18bits

(12bits data + 6 bits status)

OTP write: 18 bits

(12bits zero position + 6 bits mode selection)

read: 18bits

(12bits data + 6 bits status)

OTP write: 18 bits

(12bits zero position + 6 bits mode selection)

Pins 1 and 2 MagINCn, MagDECn: same feature as AS5045,

additional OTP option for red-yellow-green magnetic

range MagINCn, MagDECn

Incremental encoder Pin3 (DTest1_A); Pin 4 (DTest2_B); Pin 6 (Mode_Index)

2x1024 ppr (12-bit)

2x256 ppr low-jitter (10-bit)

Not used

Pin 3: not used

Pin 4:not used

Pin 6

MODE_Index pin selects fast or slow mode in the

default configuration. In case of incremental mode, the

fast mode is selected and the pin is configured as

output.

MODE_Index pin selects fast or slow mode in the

default configuration.

Pin 12 PWM output: frequency selectable by OTP:

1µs / step, 4096 steps per revolution, f=244Hz 2µs/

step, 4096 steps per revolution, f=122Hz

PWM output: frequency selectable by OTP:

1µs / step, 4096 steps per revolution, f=244Hz

2µs/ step, 4096 steps per revolution, f=122Hz

Sampling frequency selectable by MODE input pin:

2.5kHz, 10,4kHz selectable by MODE input pin:

2.5kHz, 10,4kHz

Propagation delay 384µs (slow mode) 384µs (slow mode)

96µs (fast mode) 96µs (fast mode)

Transition noise

(rms; 1sigma) 0.03 degrees maximum (slow mode) 0.03 degrees maximum (slow mode)

0.06 degrees maximum (fast mode) 0.06 degrees maximum (fast mode)

OTP programming optio ns PPTRIM; programming voltage 3.3V – 3.6V <70ºC;

3.5V – 3.6V >70ºC;

52-bit serial data protocol; CSn, PDIO and CLK

EasyZap; programming voltage 7.3V – 7.5V; Csn;

Prog and CLK; 16-bit (32-bit) serial data protocol;

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AS5245

Data Sheet - P a c kage Drawings and Markings

10 Package Drawings and Markings

The device is available in a QFN 32 (7mm x 7mm) package.

Figure 19. Package Drawings

Table 16. Package Dimensions

Symbol mm inch

Min Typ Max Min Typ Max

D 7 BSC 0.28 BSC

E 7 BSC 0.28 BSC

D1 4.18 4.28 4.38 0.165 0.169 0.172

E1 4.18 4.28 4.38 0.165 0.169 0.172

L 0.45 0.55 0.65 0.018 0.022 0.026

b 0.25 0.30 0.35 0.010 0.012 0.014

e 0.65 BSC

A 0.80 0.90 1.00 0.031 0.035 0.039

A1 0.203 REF 0.008 REF

25 32

16 9

AYWWIZZ

AS5245

Top View

Side View

otto

m Vi

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AS5245
Data Sheet - R e v is i o n   H i s t or y
Revision History
Note: Typos may not be explicitly mentioned under revision history.
Revision Date Owner Description
1.0
June 08, 2007
apg
Initial revision
July 24, 2008 Changes made to values in Table 10 - Incremental Resolution
Feb 13, 2009 Updated min, typ, max values for tDOvalid parameter in Table 6 - Timing 
Characteristics
July 15, 2009 rfu 1) Note added under Table 7 - Slow and Fast Mode Parameters
2) Output Md0, Md1 description updated, (see User Selectable Settings 
on page 20)
July 22, 2009
mub
Updated values in Table 6 - Timing Characteristics for the following 
parameters:
-t
DOvalid
-f
PWM
-PW
MIN
-PW
MAX
July 23, 2009 Updated sections Electrical Charact eristics on page 7, Timing 
Characteristics on page 11 and Detailed Description on page 12 
according to AS5145 datasheet.
1.1 Oct 19, 2009
apg
Deleted the following --
1) ‘OTP Programming Connection’ figure
2) Physical Placement of the magnet, Magnet Placement, Simulation 
Modeling
1.2 Nov 05, 2009 Timing Characteristics (page 11) - Deleted the parameter ‘PWM 
Frequency’ (fPWM)
1.3 Dec 04, 2009 Updated section Internal Timing Tolerance (page 28)

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AS5245

Data Sheet - O r d e ri n g I n f o rm a t i o n

11 Ordering Information

The devices are available as the standard products shown in Table 17.

Note: All products are RoHS compliant and Pb-free.

Buy our products or get free samples online at ICdirect: http://www.austriamicrosystems.com/ICdirect

For further information and requests, please contact us mailto:sales@austriamicrosystems.com

or find your local distributor at http://www.austriamicrosystems.com/distributor

Table 17. Ordering Information

Ordering Code Description Delivery Form Package

AS5245HQFT 12-bit fully redundant magnetic rotary encoder Tape & Reel QFN 32 (7mm x 7mm)

www.austriamicrosystems.com/AS5245 Revision 1.3 33 - 33

AS5245

Data Sheet - C o p yr i g h t s

Copyrights

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the freedom of the described devices from patent infringement. austriamicrosystems AG reserves the right to change specifications and prices at

any time and without notice. Therefore, prior to designing this product into a system, it is necessary to check with austriamicrosystems AG for

current information. This product is intended for use in normal commercial applications. Applications requiring extended temperature range,

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specifically not recommended without additional processing by austriamicrosystems AG for each application. For shipments of less than 100

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