ams Datasheet Page 1
[v2-00] 2016-Feb-05 Document Feedback
AS5145H/AS5145A/
AS5145B
12-Bit Programmable Magnetic Rotary
Encoder
The AS5145 is a contactless 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 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 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.
Ordering Information and Content Guide appear at end of
datasheet.
Key Benefits & Features
The benefits and features of AS5145H/AS5145A/AS5145B,
12-Bit Programmable Magnetic Rotary Encoder are listed
below:
Figure 1:
Added Value of Using AS5145
Benefits Features
•Highest reliability and durability •Contactless high resolution rotational position encoding
over a full turn of 360 degrees
•Simple programming •Simple user-programmable zero position and settings
•Multiple interfaces
•Serial communication interface (SSI)
•10-bit pulse width modulated (PWM) output
•Quadrature A/B and Index output signal
•Ideal for motor applications •Rational speeds up to 30,000 rpm
•Failure diagnostics •Failure detection mode for magnet placement monitoring
and loss of power supply
•Easy setup •Serial read-out of multiple interconnected AS5145 devices
using Daisy Chain mode
General Description
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AS5145H/AS5145A/AS5145B − General Description
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.
Block Diagram
The functional blocks of this device are shown below:
Figure 2:
AS5145 Automotive Rotary Encoder IC
•Great flexibility at a huge application area •Detects movement of magnet in Z-axis (Red-Yellow-Green
indicator)
•Fully automotive qualified •AEC-Q100, grade 0
•Small form factor •SSOP 16 (5.3mm x 6.2mm)
•Robust environmental tolerance •Wide temperature range: -40°C to 150°C
Benefits Features
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
ams Datasheet Page 3
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AS5145H/AS5145A/AS5145B − Pin Assignment
Figure 3:
Pin Diagram (Top View)
Pin Description
The following SSOP16 shows the description of each pin of the
standard SSOP16 package (Shrink Small Outline Package, 16
leads, body size: 5.3mm x 6.2mmm; (see Figure 3).
Figure 4:
Pin Description
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 Figure 15)
MagDECn 2
Magnet Field Magnitude Decrease. Active low.
Indicates a distance increase between the device
and the magnet. (see Figure 15)
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: VSS) and fast
(high) mode. Internal pull-down resistor (10kΩ).
VSS 7 Supply pin Negative supply voltage (GND)
Pin Assignment
2
3
4
5
6
7
89
10
11
12
13
14
15
161
MagINCn
MagDECn
DTest1_A
DTest2_B
NC
VSS
PDIO DO
CLK
CSn
PWM
NC
NC
VDD3V3
VDD5V
AS5145
Mode_Index
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AS5145H/AS5145A/AS5145B − Pin Assignment
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. Furthermore those indicators can also be used for
contactless push-button functionality.
Pin 3 and 4 are multi function pins for sync mode, sine/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 during 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 27). This pin is also used as digital input to shift
serial data through the device in daisy chain configuration, (see
page 18).
PDIO 8 Digital input
pull-down
OTP Programming Input and Data Input for
Daisy Chain Mode. Pin has an internal pull-down
resistor (74kΩ). Connect this pin to VSS if
programming is not required.
DO 9 Digital output/
tri-state Data Output of Synchronous Serial Interface
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 (50kΩ)
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
Pin Name Pin
Number Pin Type Description
ams Datasheet Page 5
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AS5145H/AS5145A/AS5145B − Pin Assignment
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) and programming
mode (see Programming the AS5145).
Pin 12 allows a single wire output of the 12-bit absolute position
value. The value is encoded into a pulse width modulated signal
with 1μs pulse width per step (1μs to 4096μs 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.
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AS5145H/AS5145A/AS5145B − Absolute Maxim um Ratings
Stresses beyond those listed in Absolute Maximum Ratings 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 is not implied. Exposure to absolute maximum
rating conditions for extended periods may affect device
reliability.
Figure 5:
Absolute Maximum Ratings
Parameter Min Max Units Comments
Electrical Parameters
DC supply voltage at pin VDD5V -0.3 7 V
DC supply voltage at pin VDD3V3 5 V
Input pin voltage -0.3 VDD5V
+0.3 V Except VDD3V3
Input current (latchup immunity) -100 100 mA EIA/JESD78 Class II Level A
Electrostatic Discharge
Electrostatic discharge ± 2 kV 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).
Relative humidity
non-condensing 585 %
Moisture sensitivity level (MSL) 3 Represents a maximum floor time of
168h
Absolute Maximum Ratings
ams Datasheet Page 7
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AS5145H/AS5145A/AS5145B − Electrical Characteristics
TAMB = -40ºC to 150ºC, VDD5V = 3.0V-3.6V (3V operation)
VDD5V = 4.5V-5.5V (5V operation) unless otherwise noted.
Figure 6:
Electrical Characteristics
Symbol Parameter Condition Min Typ Max Unit
Operating Conditions
TAMB Ambient temperature Version H/A/B -40 150 ºC
Isupp Supply current 16 21 mA
VDD5V Supply voltage at pin
VDD5V
5V operation
4.5 5.0 5.5
V
VDD3V3
Voltage 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 01V
IPROG Programming current Current during
programming 100 mA
Rprogrammed Programmed fuse
resistance (log 1)
10μA max. current @
100mV 10k ∞Ω
Runprogrammed Unprogrammed fuse
resistance (log 0)
2mA max. current @
100mV 50 100 Ω
Electrical Characteristics
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AS5145H/AS5145A/AS5145B − Electr ical Characteristics
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 1V
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(1) High level input voltage During programming 3.3 3.6 V
VIL Low level input voltage 0.3 *
VDD5V V
IIH High level input current VDD5V: 5.5V 30 100 μA
DC Characteristics CMOS Output Open Drain: MagINCn, MagDECn
IOZ Open drain leakage
current 1μA
VOL Low level output voltage VSS +
0.4 V
IOOutput current
VDD5V: 4.5V 4
mA
VDD5V: 3V 2
Symbol Parameter Condition Min Typ Max Unit
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AS5145H/AS5145A/AS5145B − Electrical Characteristics
Note(s):
1. Either with 3.3V or 5V supply.
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
Symbol Parameter Condition Min Typ Max Unit
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AS5145H/AS5145A/AS5145B − Electr ical Characteristics
Magnetic Input Specification
TAMB = -40°C to 150°C, VDD5V = 3.0V to 3.6V (3V operation)
VDD5V = 4.5 to 5.5V (5V operation) unless otherwise noted.
Two-pole cylindrical diametrically magnetized source:
Figure 7:
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
Max. offset between
defined device center and
magnet axis
(see Figure 34)
0.25 mm
Ecc Eccentricity Eccentricity of magnet
center to rotational axis 100 μm
Recommended magnet
material and temperature
drift
NdFeB (Neodymium Iron
Boron) -0.12
%/K
SmCo (Samarium Cobalt) -0.035
ams Datasheet Page 11
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AS5145H/AS5145A/AS5145B − Electrical Characteristics
System Specifications
TAMB = -40°C to 150°C, VDD5V = 3.0 to 3.6V (3V operation)
VDD5V = 4.5 to 5.5V (5V operation) unless otherwise noted.
Figure 8:
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 =25 ºC.
± 0.5 deg
INLtemp Integral non-linearity
(optimum)
Maximum error with respect to
the best line fit.
Centered magnet without
calibration,
TAMB = -40°C to 150ºC
± 0.9 deg
INL Integral non-linearity
Best line fit =
(Errmax – Errmin) / 2
Over displacement tolerance
with 6mm diameter magnet,
without calibration,
TAMB = -40°C 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
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
tdelayINC
System propagation
delay incremental
output AS5145A and
AS5145B: delay of ADC,
DSP and incremental
interface
Only fast mode possible 192 μs
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AS5145H/AS5145A/AS5145B − Electr ical Characteristics
Figure 9:
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.
fSInternal sampling rate for
absolute output:
TAMB = 25ºC, slow mode
(MODE=0 or open) 2.48 2.61 2.74
kHz
TAMB = -40°C 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°C to 150ºC, fast
mode (MODE=1) 9.38 10.42 11.46
CLK/SEL Read-out frequency Max. clock frequency to read
out serial data 1MHz
Symbol Parameter Condition Min Typ Max Unit
180° 360
°
0
°
0
512
1023
α
α
10bit code
0
1
2
0.35°INL
Ideal curve
Actual curve
TN
512
1023
DNL+1LSB
[degrees]
ams Datasheet Page 13
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AS5145H/AS5145A/AS5145B − Timing Characteristics
TAMB = -40°C to 150 ºC, VDD5V = 3.0 to 3.6V (3V operation)
VDD5V = 4.5 to 5.5V (5V operation), unless otherwise noted.
Figure 10:
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 =high; 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 220 244 268 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 single 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
Timing Characteristics
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AS5145H/AS5145A/AS5145B − Detailed Description
The AS5145 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 AS5145 provides
accurate high-resolution absolute angular position
information. For this purpose a Coordinate Rotation Digital
Computer (CORDIC) calculates the angle and the magnitude of
the Hall array signals.
The DSP is also used to provide digital information at the
outputs MagINCn and MagDECn that indicate movements of
the used magnet towards or away from the device’s surface. A
small low cost diametrically magnetized (two-pole) standard
magnet provides the angular position information (see
Figure 33).
The AS5145 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 AS5145 is tolerant to magnet
misalignment and magnetic stray fields due to differential
measurement technique and Hall sensor conditioning circuitry.
Figure 11:
Typical Arrangement of AS5145 and Magnet
Detailed Description
ams Datasheet Page 15
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AS5145H/AS5145A/AS5145B − Detailed Description
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.
Setup the Mode pin affects the following parameters:
Figure 12:
Slow and Fast Mode Parameters
Note(s):
1. A change of the Mode during operation is not allowed. The setup must be constant during power up and during operation.
Parameter Slow Mode
(Mode = Low or Open) Fast Mode
(Mode = High, VDD= 5V)
Sampling rate 2.61 kHz (384 μs) 10.42 kHz (96μs)
Transition 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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AS5145H/AS5145A/AS5145B − Detailed Description
Synchronous Serial Interface (SSI)
Figure 13:
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.
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 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, Mag IN C, MagDEC)
Placing the magnet above the chip, angular values increase in
clockwise direction by default.
CSn
CLK
DO
tDO valid
Angular Position Data
tDO active Status Bits tDO Tristate
tCSn tCLK FE
tCLK FE
TCLK/2
1
D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 OCF COF LIN Mag
INC Mag
DEC Even
PAR
818 1
D11
D10
D11
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AS5145H/AS5145A/AS5145B − Detailed Description
Data D11:D0 is valid, when the status bits have the following
configurations:
Figure 14:
Status Bit Options
Note(s):
1. MagInc=MagDec=1 is only recommended in YELLOW mode (see Figure 15)
Z-Axis Range Indication (Push Button Feature,
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 pins
(pins #1 and 2) and as status bits in the serial data stream (see
Figure 15).
In the default state, the status bits MagINC, MagDec and pins
MagINCn, MagDECn have the following function:
Figure 15:
Magnetic Field Strength Red-Yellow-Green Indicator
Note(s):
1. 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.
OCF COF LIN Mag INC Mag DEC Parity
10 0
00
Even checksum
of bits 1:15
01
10
11
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, ~45mT to 75mT)
110OnOff
YELLOW range: magnetic field is ~ 25mT to 45mT or
~75mT to 135mT. The AS5145 can still be operated in this
range, but with slightly reduced accuracy.
1 1 1 On On
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
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AS5145H/AS5145A/AS5145B − Detailed Description
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 in
range. It is low in all other cases (see Figure 15).
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
versions (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 recommended.
Figure 16:
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.
01 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
ams Datasheet Page 19
[v2-00] 2016-Feb-05 Document Feedback
AS5145H/AS5145A/AS5145B − 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=Index = high) can be used as an
indicator for the external controller to shorten the waiting
time at power-up. Instead of waiting for the specified
maximum power up-time (0), the controller can start
requesting data from the AS5145 as soon as the state
(A=B=Index = high) is cleared.
•CSn = high or open at power-up: In this mode, the
incremental outputs (A, B, Index) will remain at logic high
state, until CSn goes low or a low pulse is applied at CSn.
This mode allows intentional disabling of the incremental
outputs until, for example the system microcontroller is
ready to receive data.
Figure 17:
Incremental Output
The hysteresis trimming is done at the final test (factory
trimming) and set to 4 LSB, related to a 12-bit number.
Rext 5kΩ≤
Mode_Index
D Test2_B
D Test1_A
1 LSB
Programmed
Zero Position
ClockWise
3 LSB
Counter ClockWise
Page 20 ams Datasheet
Document Feedback [v2-00] 2016-Feb-05
AS5145H/AS5145A/AS5145B − Detailed Description
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 18). 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 18:
Hysteresis Window for Incremental Outputs
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.
Magnet Pos ition
Hysteresis :
0.35°
X +2
Incr emental
Output
Indication
Clockwise Direct ion
Counter clockwise Dire ction
X +4
XX X +2 X +4 X +5X +3X +1
X +1
X +3
X +6
X +5
X +6
ams Datasheet Page 21
[v2-00] 2016-Feb-05 Document Feedback
AS5145H/AS5145A/AS5145B − Detailed Description
Sync Mode
This mode is used to synchronize the external electronic with
the AS5145. 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 19:
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.
Sine/Cosine Mode
This mode can be enabled by setting the OTP Factory-bit FS2.
If this mode is activated the 16 bit sine and 16 bit cosine 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.
DTest1_A
DTest1_B
400µs (100µs)
Page 22 ams Datasheet
Document Feedback [v2-00] 2016-Feb-05
AS5145H/AS5145A/AS5145B − Detailed Description
Daisy Chain Mode
The daisy chain mode allows connection of several AS5145s in
series, while still keeping just one digital input for data transfer
(see “Data IN” in Figure 20). 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 21).
Figure 20:
Daisy Chain Hardware Configuration
Figure 21:
Daisy Chain Mode Data Transfer
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
CSn
CLK
DO
tDO valid Angular Position Data
tDO active Status Bits
tCLK FE TCLK/2
1
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
ams Datasheet Page 23
[v2-00] 2016-Feb-05 Document Feedback
AS5145H/AS5145A/AS5145B − Detailed Description
Pulse Width Modulation (PWM) Output
The AS5145 provides a pulse width modulated output (PWM),
whose duty cycle is proportional to the measured angle. For
angle position 0 to 4094
Position =
Examples:
1. An angle position of 180° 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 359.8° will generate a pulse width
ton = 4095μs and a pause toff of 3 μs resulting in Position
= 4094 after the calculation:
4095 * 4098 / (4095 + 3) -1 = 4094
Exception:
1. An angle position of 359.9° will generate a pulse width
ton = 4097μs and a pause toff of 1 μs resulting in Position
= 4096 after the calculation:
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 22:
PWM Output Signal
(EQ1)
ton 4098⋅
ton toff
+()
--------------------------1–
4098µs
4097µs
1/fPWM
PWMAX
PWMIN
359.91 deg
(Pos 4095)
0 deg
(Pos 0)
Angle
1µs
Page 24 ams Datasheet
Document Feedback [v2-00] 2016-Feb-05
AS5145H/AS5145A/AS5145B − Detailed Description
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). With PWMhalfEN = 0 the PWM timing is as shown
in Figure 23:
Figure 23:
PWM Signal Parameters (Default Mode)
When PWMhalfEN = 1, the PWM timing is as shown in Figure 24:
Figure 24:
PWM Signal Parameters with Half Frequency (OTP Option)
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 4097 μs •Position 4095d
•Angle 359.91 deg
Symbol Parameter Typ Unit Note
fPWM PWM frequency 122 Hz Signal period: 8194μs
PWMIN MIN pulse width 2 μs •Position 0d
•Angle 0 deg
PWMAX MAX pulse width 8194 μs •Position 4095d
•Angle 359.91 deg
ams Datasheet Page 25
[v2-00] 2016-Feb-05 Document Feedback
AS5145H/AS5145A/AS5145B − Detailed Description
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 AS5145 can be used as direct
replacement of potentiometers.
Figure 25:
Simple 2nd Order Passive RC Low Pass Filter
Figure 25 shows an example of a simple passive low pass filter
to generate the analog output.
R1,R2
≥
10k
Ω
C1,C2
≥
2.2μF / 6V
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.
R1 R2 analog out
Pin12
PWM
Pin7
VSS
C1 C2 VDD
0V 0º 360º
(EQ2)
Page 26 ams Datasheet
Document Feedback [v2-00] 2016-Feb-05
AS5145H/AS5145A/AS5145B − Application I nformation
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
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 that 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
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.
Application Information
ams Datasheet Page 27
[v2-00] 2016-Feb-05 Document Feedback
AS5145H/AS5145A/AS5145B − Application Information
• 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.
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 (see
Figure 28).
Note(s): 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 into the OTP register.
Page 28 ams Datasheet
Document Feedback [v2-00] 2016-Feb-05
AS5145H/AS5145A/AS5145B − Application I nformation
OTP Memory Assignment
Figure 26:
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
ams Datasheet Page 29
[v2-00] 2016-Feb-05 Document Feedback
AS5145H/AS5145A/AS5145B − Application Information
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 Figure 16).
•Output Md1: Setting this bit enables sync- or 12-bit
incremental mode (see Figure 16).
• Z [11:0]: Programmable Zero / Index Position
• 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
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
17 ChipID0
18-bit Chip ID
ID Section
16 ChipID1
::
0ChipID17
mbit0 Factory Bit 0
Bit Symbol Function
Page 30 ams Datasheet
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AS5145H/AS5145A/AS5145B − Application I nformation
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.
Figure 27:
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 000000000000000 0 0 0
00001 100000000000000 0 0 0
00010 0 10000000000000 0 0 0
00011 0 0 1000000000000 0 0 0
00100 0 0 0 100000000000 0 0 0
00101 0 0 0 0 10000000000 0 0 0
00110 000001000000000 0 0 0
00111 000000100000000 0 0 0
01000 000000010000000 0 0 0
01001 000000001000000 0 0 0
01010 000000000100000 0 0 0
01011 000000000010000 0 0 0
01100 000000000001000 0 0 0
01101 000000000000100 0 0 0
01110 0000000000000100 00
01111 000000000000001000
10000 000000000000000 100
10001 000000000000000 0 10
10010 000000000000000 0 0 1
10101 111111111111111 1 1 1
ams Datasheet Page 31
[v2-00] 2016-Feb-05 Document Feedback
AS5145H/AS5145A/AS5145B − Application Information
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.
OTP Register Entry and Exit Condition
For timing options, refer to Programming the AS5145.
Figure 28:
OTP Access Timing Diagram
To avoid accidental modification of the OTP during normal
operation, each OTP access (Load, Write, Read, Program)
requires a defined entry and exit procedure, using the CSn, PDIO
and CLK signals as shown in Figure 28.
OTP Access
Setup Condition
Operation Mode Selection Exit Condition
CSn
PDIO
CLK
Page 32 ams Datasheet
Document Feedback [v2-00] 2016-Feb-05
AS5145H/AS5145A/AS5145B − Application I nformation
Figure 29:
OTP Programming Connection
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 30). 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 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.
AS5145 Dem oboa rd
2
3
4
5
6
7
89
10
11
12
13
14
15
161MagINCn
MagDECn
DTest1_A
DTest2_B
NC
Mode_Index
VSS
PDIO DO
CLK
CSn
PWM
NC
NC
VDD3V3
VDD5V
AS5145
IC1
7
2
3
4
5
6
1
10n 2.2µF
µC
Cap only required for OTP programming
GND
PROG
CSN
DO
CLK
5VUSB
VDD3V3
VSS
+
10µF
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,
keep these 6 wires
as short as possible!
max. length = 2 inches (5 cm)
22k
3V3
Page 34 ams Datasheet
Document Feedback [v2-00] 2016-Feb-05
AS5145H/AS5145A/AS5145B − Application I nformation
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
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 32).
For 5V operation, the 5V supply is connected to pin VDD5V,
while VDD3V3 (LDO output) must be buffered by a 1μF to 10μF
capacitor, which is supposed to be placed close to the supply
pin (see Figure 32) with recommended 2.2μF).
Note(s): 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 32:
Connections for 5V / 3.3V Supply Voltages
Internal
VDD
LDO
I
N
T
E
R
F
A
C
E
VSS
VDD5V
VDD3V3
100nF
4.5 - 5.5V
+
-
2.2 ... 10µF
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
ams Datasheet Page 35
[v2-00] 2016-Feb-05 Document Feedback
AS5145H/AS5145A/AS5145B − Application Information
A buffer capacitor of 100nF is recommended in both cases close
to pin VDD 5V. Note that pin VDD 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 jitter of the measured angle.
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 to ±75mT
(peak).
The magnet’s field strength is verified using a gauss-meter. The
magnetic field Bv at a given distance, along a concentric circle
with a radius of 1.1mm (R1) is in the range of
±45mT to ±75mT(see Figure 33).
Figure 33:
Typical Magnet (6x3mm) and Magnetic Field Distribution
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
SN
Page 36 ams Datasheet
Document Feedback [v2-00] 2016-Feb-05
AS5145H/AS5145A/AS5145B − Application I nformation
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 34:
Defined Chip Center and Magnet Displacement Radius
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
magnet 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 specified limits (see Figure 34). 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 stays 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
indicated by MagINCn (pin 1) and MagDECn (pin 2), (see
Figure 4).
Area of recommended maximum mag-
net misalignment
Defined
center
Rd
3.9mm 3.9mm
2.4325mm
2.4325mm
1
ams Datasheet Page 37
[v2-00] 2016-Feb-05 Document Feedback
AS5145H/AS5145A/AS5145B − Application Information
Failure Diagnostics
The AS5145 also offers several diagnostic and failure detection
features:
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).
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 (~10kΩ) 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 Figure 15). 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
(~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.
Page 38 ams Datasheet
Document Feedback [v2-00] 2016-Feb-05
AS5145H/AS5145A/AS5145B − Application I nformation
Angular Output Tolerances
Accuracy
Accuracy is defined as the error between measured angle and
actual angle. It is influenced by several factors:
•The non-linearity of the analog-digital converters
•Internal gain and mismatch errors
•Non-linearity due to misalignment of the magnet
As a sum of all these errors, the accuracy with centered magnet
= (Errmax – Errmin)/2 is specified as better than ±0.5 degrees
@ 25ºC (see Figure 36).
Misalignment of the magnet further reduces the accuracy.
Figure 35 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 2x2mm (79x79mil) with a step size of
100μm.
For each misalignment step, the measurement as shown in
Figure 36 is repeated and the accuracy
(Errmax – Errmin)/2 (e.g. 0.25º in Figure 36) is entered as the
Z-axis in the 3D-graph.
Figure 35:
Example of Linearity Error Over XY Misalignment
-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
ams Datasheet Page 39
[v2-00] 2016-Feb-05 Document Feedback
AS5145H/AS5145A/AS5145B − Application Information
The maximum non-linearity error on this example is better than
±1 degree (inner circle) over a misalignment radius of ~0.7mm.
For volume production, the placement tolerance of the IC
within the package (±0.235mm) must also be taken into
account.
The total nonlinearity error over process tolerances,
temperature and a misalignment circle radius of 0.25mm is
specified better than ±1.4 degrees. The magnet used for this
measurement was a cylindrical NdFeB (Bomatec® BMN-35H)
magnet with 6mm diameter and 2.5mm in height.
Figure 36:
Example of Linearity Error Over 360º
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)x1 in fast mode (pin MODE = high) and
0.03 degrees rms (1 sigma)x1 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 0.03ºrms to 0.015ºrms (1 sigma) in slow mode.
-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
Page 40 ams Datasheet
Document Feedback [v2-00] 2016-Feb-05
AS5145H/AS5145A/AS5145B − Application I nformation
• PWM Interface: If the PWM interface is used as an analog
output by adding a low pass filter, the transition noise can
be reduced by lowering the cutoff frequency of the filter.
If the PWM interface is used as a digital interface with a
counter at the receiving side, the transition noise 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(s): Statistically, 1 sigma represents 68.27% of readings
and 3 sigma represents 99.73% of readings.
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 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
nslowmode =
nfastmode =
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 Figure 12). 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 speeds of
up to 15,000 rpm, even at the highest resolution of 12 bits
(4096 pulses per revolution).
(EQ3)
60
rpm 384()μs⋅
-----------------------------------
(EQ4)
60
rmp 96μs⋅
---------------------------
ams Datasheet Page 41
[v2-00] 2016-Feb-05 Document Feedback
AS5145H/AS5145A/AS5145B − Application Information
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 * prop.delay
where:
esampling = angular error [º]
rpm = rotating speed [rpm]
prop.delay = propagation delay [seconds]
Note(s): Since the propagation delay is known, it can be
automatically compensated by the control unit processing the
data from the AS5145.
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 tolerance influences the ADC
sampling rate and the pulse width of the PWM output:
•Absolute output; SSI interface: A new angular value is
updated every 96μs (typ) in fast mode and every 384μs
(typ) in slow mode.
•PWM output: A new angular value is updated every 384μs
(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)
Position =
(EQ5)
(EQ6)
ton 4097⋅
ton toff
+()
--------------------------1–
Page 42 ams Datasheet
Document Feedback [v2-00] 2016-Feb-05
AS5145H/AS5145A/AS5145B − Application I nformation
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 considered, as the AS5145 operates
with magnetic field strengths from ±45mT to ±75mT.
Example: A NdFeB magnet has a field strength of 75mT @ –40ºC
and a temperature coefficient of -0.12% per Kelvin. The
temperature change is from -40ºC to 125ºC = 165K.The
magnetic field change is: 165 x -0.12% = -19.8%, which
corresponds to 75mT at -40ºC and 60mT at 125ºC.
The AS5145 can compensate for this temperature related field
strength change automatically, no user adjustment is required.
Accuracy Over Temperature
The influence of temperature in the absolute accuracy is very
low. While the accuracy is less than or equal to ±0.5º at room
temperature, 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 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.
ams Datasheet Page 43
[v2-00] 2016-Feb-05 Document Feedback
AS5145H/AS5145A/AS5145B − Application Information
Differences Between AS5145H, AS5145A and
AS5145B
Figure 37:
Functional Differences
Function AS5145H AS5145A AS5145B
Filtering mode Selectable by customer via
Mode pin (see Figure 12) 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
Page 44 ams Datasheet
Document Feedback [v2-00] 2016-Feb-05
AS5145H/AS5145A/AS5145B − Package Drawings & Markings
The device is available in SSOP 16 (5.3mm x 6.2mm).
Figure 38:
Package Drawings and Dimensions
Note(s):
1. Dimensions and tolerancing conform to ASME Y14.5M-1994.
2. All dimensions are in millimeters. Angles are in degrees.
Figure 39:
Package Code: YYWWMZZ
YY WW MZZ @
Manufacturing year Manufacturing week Plant identifier Assembly traceability code Sublot identifier
Package Drawings & Markings
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- -
Q 0º4º8º
N16
Green
RoHS
ams Datasheet Page 47
[v2-00] 2016-Feb-05 Document Feedback
AS5145H/AS5145A/AS5145B − Ordering & Contact Information
The devices are available as the standard products shown in
Figure 42.
Figure 42:
Ordering Information
Buy our products or get free samples online at:
www.ams.com/ICdirect
Technical Support is available at:
www.ams.com/Technical-Support
Provide feedback about this document at:
www.ams.com/Document-Feedback
For further information and requests, e-mail us at:
ams_sales@ams.com
For sales offices, distributors and representatives, please visit:
www.ams.com/contact
Headquarters
ams AG
Tobelbaderstrasse 30
8141 Premstaetten
Austria, Europe
Tel: +43 (0) 3136 500 0
Website: www.ams.com
Ordering Code Description Package Delivery
Form Delivery
Quantity
AS5145H-HSST 12-Bit Programmable
Magnetic Rotary Encoder
SSOP 16
(5.3mm x 6.2mm)
Tape & Reel
2000 pcs/reel
AS5145H-HSSM 500 pcs/reel
AS5145A-HSST Pre-programmed 10-bit
incremental Tape & Reel
2000 pcs/reel
AS5145A-HSSM 500 pcs/reel
AS5145B-HSST Pre-programmed 12-bit
incremental Tape & Reel
2000 pcs/reel
AS5145B-HSSM 500 pcs/reel
Ordering & Contact Information
Page 48 ams Datasheet
Document Feedback [v2-00] 2016-Feb-05
AS5145H/AS5145A/AS5145B − RoHS Compliant & ams Green Statement
RoHS: The term RoHS compliant means that ams AG products
fully comply with current RoHS directives. Our semiconductor
products do not contain any chemicals for all 6 substance
categories, including the requirement that lead not exceed
0.1% by weight in homogeneous materials. Where designed to
be soldered at high temperatures, RoHS compliant products are
suitable for use in specified lead-free processes.
ams Green (RoHS compliant and no Sb/Br): ams Green
defines that in addition to RoHS compliance, our products are
free of Bromine (Br) and Antimony (Sb) based flame retardants
(Br or Sb do not exceed 0.1% by weight in homogeneous
material).
Important Information: The information provided in this
statement represents ams AG knowledge and belief as of the
date that it is provided. ams AG bases its knowledge and belief
on information provided by third parties, and makes no
representation or warranty as to the accuracy of such
information. Efforts are underway to better integrate
information from third parties. ams AG has taken and continues
to take reasonable steps to provide representative and accurate
information but may not have conducted destructive testing or
chemical analysis on incoming materials and chemicals. ams AG
and ams AG suppliers consider certain information to be
proprietary, and thus CAS numbers and other limited
information may not be available for release.
RoHS Compliant & ams Green
Statement
ams Datasheet Page 49
[v2-00] 2016-Feb-05 Document Feedback
AS5145H/AS5145A/AS5145B − Copyrights & Disclaimer
Copyright ams AG, Tobelbader Strasse 30, 8141 Premstaetten,
Austria-Europe. Trademarks Registered. All rights reserved. The
material herein may not be reproduced, adapted, merged,
translated, stored, or used without the prior written consent of
the copyright owner.
Devices sold by ams AG are covered by the warranty and patent
indemnification provisions appearing in its General Terms of
Trade. ams AG makes no warranty, express, statutory, implied,
or by description regarding the information set forth herein.
ams AG reserves the right to change specifications and prices
at any time and without notice. Therefore, prior to designing
this product into a system, it is necessary to check with ams AG
for current information. This product is intended for use in
commercial applications. Applications requiring extended
temperature range, unusual environmental requirements, or
high reliability applications, such as military, medical
life-support or life-sustaining equipment are specifically not
recommended without additional processing by ams AG for
each application. This product is provided by ams AG “AS IS”
and any express or implied warranties, including, but not
limited to the implied warranties of merchantability and fitness
for a particular purpose are disclaimed.
ams AG shall not be liable to recipient or any third party for any
damages, including but not limited to personal injury, property
damage, loss of profits, loss of use, interruption of business or
indirect, special, incidental or consequential damages, of any
kind, in connection with or arising out of the furnishing,
performance or use of the technical data herein. No obligation
or liability to recipient or any third party shall arise or flow out
of ams AG rendering of technical or other services.
Copyrights & Disclaimer
Page 50 ams Datasheet
Document Feedback [v2-00] 2016-Feb-05
AS5145H/AS5145A/AS5145B − Document Status
Document Status Product Status Definition
Product Preview Pre-Development
Information in this datasheet is based on product ideas in
the planning phase of development. All specifications are
design goals without any warranty and are subject to
change without notice
Preliminary Datasheet Pre-Production
Information in this datasheet is based on products in the
design, validation or qualification phase of development.
The performance and parameters shown in this document
are preliminary without any warranty and are subject to
change without notice
Datasheet Production
Information in this datasheet is based on products in
ramp-up to full production or full production which
conform to specifications in accordance with the terms of
ams AG standard warranty as given in the General Terms of
Trade
Datasheet (discontinued) Discontinued
Information in this datasheet is based on products which
conform to specifications in accordance with the terms of
ams AG standard warranty as given in the General Terms of
Trade, but these products have been superseded and
should not be used for new designs
Document Status
ams Datasheet Page 51
[v2-00] 2016-Feb-05 Document Feedback
AS5145H/AS5145A/AS5145B − Revision Information
Note(s):
1. Page and figure numbers for the previous version may differ from page and figure numbers in the current revision.
2. Correction of typographical errors is not explicitly mentioned.
Changes from 1.17 (2013-Jul-04) to current revision 2-00 (2016-Feb-05) Page
Content was updated to the latest ams design
Added benefits to Figure 1 1
Updated Figure 6 and text above it 7
Updated text above Figure 7 10
Updated text above Figure 8 11
Updated text above Figure 10 13
Updated Figure 39 44
Updated Figure 42 47
Revision Information
Page 52 ams Datasheet
Document Feedback [v2-00] 2016-Feb-05
AS5145H/AS5145A/AS5145B − Conte nt Guide
1 General Description
1 Key Benefits & Features
2 Applications
2 Block Diagram
3 Pin Assignment
3 Pin Description
6Absolute Maximum Ratings
7 Electrical Characteristics
10 Magnetic Input Specification
11 System Specifications
13 Timing Characteristics
14 Detailed Description
15 Mode_Index Pin
16 Synchronous Serial Interface (SSI)
18 Incremental Mode
21 Sync Mode
21 Sin/Cosine Mode
22 Daisy Chain Mode
23 Pulse Width Modulation (PWM) Output
24 Changing the PWM Frequency
25 Analog Output
26 Application Information
26 Programming the AS5145
27 Zero Position Programming
28 OTP Memory Assignment
29 User Selectable Settings
29 OTP Default Setting
30 Redundancy
31 Redundant Programming Option
31 OTP Register Entry and Exit Condition
32 Alignment Mode
34 3.3V / 5V Operation
35 Selecting Proper Magnet
36 Physical Placement of the Magnet
36 Magnet Placement
37 Failure Diagnostics
37 Magnetic Field Strength Diagnosis
37 Power Supply Failure Detection
38 Angular Output Tolerances
38 Accuracy
39 Transition Noise
40 High Speed Operation
41 Propagation Delays
41 Internal Timing Tolerance
42 Temperature
42 Accuracy Over Temperature
43 Differences Between AS5145H, AS5145A and AS5145B
Content Guide
