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AS5145H/AS5145A/
AS5145B
12-Bit Programmable Magnetic Rotary
Encoder
General Description
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
ams Datasheet
[v2-00] 2016-Feb-05
Page 1
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AS5145H/AS5145A/AS5145B − General Description
Benefits
Features
• 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
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
VDD3V3
VDD5V
MagINCn
MagDECn
LDO 3.3V
PWM
Interface
Sin
Hall Array
&
Frontend
Amplifier
Mux
Cos
PWM
Ang
DSP
Mag
Absolute
Interface
(SSI)
DO
CSn
CLK
OTP
Register
AS5145
PDIO
Incremental
Interface
DTEST1_A
DTEST2_B
Mode_Index
Page 2
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ams Datasheet
[v2-00] 2016-Feb-05
AS5145H/AS5145A/AS5145B − Pin Assignment
Pin Assignment
Figure 3:
Pin Diagram (Top View)
1
16
VDD5V
MagDECn
2
15
VDD3V3
DTest1_A
3
14
NC
DTest2_B
4
13
NC
NC
5
12
PWM
Mode_Index
6
11
CSn
VSS
7
10
CLK
PDIO
8
9
DO
AS5145
MagINCn
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
MagINCn
1
Pin Type
Digital output open
drain
MagDECn
2
DTest1_A
3
Description
Magnet Field Magnitude Increase. Active low.
Indicates a distance reduction between the
magnet and the device surface. (see Figure 15)
Magnet Field Magnitude Decrease. Active low.
Indicates a distance increase between the device
and the magnet. (see Figure 15)
Test output in default mode
Digital output
DTest2_B
4
NC
5
-
Mode_Index
6
Digital input/output
pull-down
VSS
7
Supply pin
ams Datasheet
[v2-00] 2016-Feb-05
Test output in default mode
Must be left unconnected
Select between slow (open, low: VSS) and fast
(high) mode. Internal pull-down resistor (10kΩ).
Negative supply voltage (GND)
Page 3
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AS5145H/AS5145A/AS5145B − Pin Assignment
Pin
Number
Pin Type
Description
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
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
Pulse Width Modulation
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).
Page 4
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ams Datasheet
[v2-00] 2016-Feb-05
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.
ams Datasheet
[v2-00] 2016-Feb-05
Page 5
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AS5145H/AS5145A/AS5145B − Absolute Maximum Ratings
Absolute Maximum 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
DC supply voltage at pin VDD3V3
7
V
5
V
Input pin voltage
-0.3
VDD5V
+0.3
V
Input current (latchup immunity)
-100
100
mA
Except VDD3V3
EIA/JESD78 Class II Level A
Electrostatic Discharge
Electrostatic discharge
±2
kV
JESD22-A114E
Temperature Ranges and Storage Conditions
Storage temperature
-55
150
Package body temperature
Relative humidity
non-condensing
Moisture sensitivity level (MSL)
Page 6
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5
3
ºC
Min -67ºF; Max 302ºF
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).
85
%
Represents a maximum floor time of
168h
ams Datasheet
[v2-00] 2016-Feb-05
AS5145H/AS5145A/AS5145B − Electrical Characteristics
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
150
ºC
16
21
mA
5.0
5.5
Operating Conditions
TAMB
Ambient temperature
Isupp
Supply current
VDD5V
Supply voltage at pin
VDD5V
VDD3V3
Voltage regulator
output voltage at pin
VDD3V3
VDD5V
Supply voltage at pin
VDD5V
VDD3V3
Supply voltage at pin
VDD3V3
VON
Voff
Version H/A/B
-40
4.5
5V operation
3.3V operation
(pin VDD5V and
VDD3V3 connected)
Power-on reset
thresholds
On voltage; 300mV typ.
hysteresis
Power-on reset
thresholds
Off voltage; 300mV typ.
hysteresis
V
3.0
3.3
3.6
3.0
3.3
3.6
V
3.0
3.3
3.6
1,37
2.2
2.9
DC supply voltage 3.3V
(VDD3V3)
V
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
Programmed fuse
resistance (log 1)
10μA max. current @
100mV
10k
∞
Ω
Unprogrammed fuse
resistance (log 0)
2mA max. current @
100mV
50
100
Ω
Rprogrammed
Runprogrammed
ams Datasheet
[v2-00] 2016-Feb-05
Page 7
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AS5145H/AS5145A/AS5145B − Electrical Characteristics
Symbol
Parameter
Condition
Min
Typ
Max
Unit
DC Characteristics CMOS Schmitt-Trigger Inputs: CLK, CSn (CSn = Internal Pull-Up)
VIH
High level input voltage
VIL
Low level input voltage
VIon- VIoff
Normal operation
0.7 *
VDD5V
V
0.3 *
VDD5V
Schmitt Trigger
hysteresis
1
V
V
ILEAK
Input leakage current
CLK only
-1
1
IIL
Pull-up low level input
current
CSn only, VDD5V: 5.0V
-30
-100
μA
DC Characteristics CMOS / Program Input: PDIO
VIH
High level input voltage
VPROG(1)
High level input voltage
VIL
Low level input voltage
IIH
High level input current
During programming
VDD5V: 5.5V
0.7 *
VDD5V
VDD5V
V
3.3
3.6
V
0.3 *
VDD5V
V
100
μA
1
μA
VSS +
0.4
V
30
DC Characteristics CMOS Output Open Drain: MagINCn, MagDECn
IOZ
Open drain leakage
current
VOL
Low level output voltage
IO
Page 8
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VDD5V: 4.5V
4
VDD5V: 3V
2
Output current
mA
ams Datasheet
[v2-00] 2016-Feb-05
AS5145H/AS5145A/AS5145B − Electrical Characteristics
Symbol
Parameter
Condition
Min
Typ
Max
Unit
DC Characteristics CMOS Output: PWM
VOH
High level output
voltage
VOL
Low level output voltage
IO
VDD5V –
0.5
V
VSS
+0.4
VDD5V: 4.5V
4
VDD5V: 3V
2
Output current
V
mA
DC Characteristics CMOS Output: A, B, Index
VOH
High level output
voltage
VOL
Low level output voltage
IO
VDD5V –
0.5
V
VSS
+0.4
VDD5V: 4.5V
4
VDD5V: 3V
2
Output current
V
mA
DC Characteristics Tri-State CMOS Output: DO
VOH
High level output
voltage
VOL
Low level output voltage
IO
IOZ
VDD5V –
0.5
V
VSS
+0.4
VDD5V: 4.5V
4
VDD5V: 3V
2
Output current
Tri-state leakage current
V
mA
1
μA
Note(s):
1. Either with 3.3V or 5V supply.
ams Datasheet
[v2-00] 2016-Feb-05
Page 9
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AS5145H/AS5145A/AS5145B − Electrical 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
dmag
Diameter
tmag
Thickness
Condition
Recommended magnet:
Ø 6mm x 2.5mm for
cylindrical magnets
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
Boff
Magnetic offset
Field non-linearity
fmag_abs
Input frequency
(rotational speed of
magnet)
4
6
Max
Unit
mm
2.5
mm
mT
Constant magnetic stray
field
± 10
mT
Including offset gradient
5
%
153 rpm @ 4096
positions/rev; fast mode
2.54
45
Hz
38 rpm @ 4096
positions/rev; slow mode
0.63
0.25
mm
100
μm
Disp
Displacement radius
Ecc
Eccentricity
Eccentricity of magnet
center to rotational axis
Page 10
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Typ
75
Max. offset between
defined device center and
magnet axis
(see Figure 34)
Recommended magnet
material and temperature
drift
Min
NdFeB (Neodymium Iron
Boron)
-0.12
SmCo (Samarium Cobalt)
-0.035
%/K
ams Datasheet
[v2-00] 2016-Feb-05
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
RES
Parameter
Condition
Min
Typ
Max
Unit
12
bit
Resolution
0.088 deg
Integral non-linearity
(optimum)
Maximum error with respect to
the best line fit. Centered
magnet without calibration,
TAMB =25 ºC.
± 0.5
deg
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
INLopt
INLtemp
1 sigma, fast mode (MODE = 1)
TN
Transition noise
1 sigma, slow mode
(MODE = 0 or open)
Fast mode (Mode = 1);
Until status bit OCF = 1
tPwrUp
tdelay
tdelayINC
0.06
0.03
20
ms
Power-up time
System propagation
delay
absolute output : delay
of ADC, DSP and
absolute interface
System propagation
delay incremental
output AS5145A and
AS5145B: delay of ADC,
DSP and incremental
interface
ams Datasheet
[v2-00] 2016-Feb-05
deg
RMS
Slow mode (Mode = 0 or open);
Until OCF = 1
80
Fast mode (MODE = 1)
96
Slow mode (MODE = 0 or open)
384
Only fast mode possible
192
μs
μs
Page 11
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AS5145H/AS5145A/AS5145B − Electrical Characteristics
Symbol
fS
fS
CLK/SEL
Parameter
Condition
Internal sampling rate for
absolute output:
Internal sampling rate for
absolute output
TAMB = 25ºC, slow mode
(MODE=0 or open)
Min
Typ
Max
2.48
2.61
2.74
kHz
TAMB = -40°C to 150ºC, slow
mode (MODE=0 or open)
2.35
2.61
2.87
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
Max. clock frequency to read
out serial data
Read-out frequency
Unit
11.46
1
MHz
Figure 9:
Integral and Differential Non-Linearity Example
1023
α 10bit code
1023
Actual curve
2
TN
DNL+1LSB
1
0
512
Ideal curve
INL
0.35°
512
0
0°
180°
360 °
α [degrees]
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.
Page 12
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ams Datasheet
[v2-00] 2016-Feb-05
AS5145H/AS5145A/AS5145B − Timing Characteristics
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
100
ns
Synchronous Serial Interface (SSI)
Data output activated
(logic high)
Time between falling edge of
CSn and data output
activated
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
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
fCLK
Read-out frequency
Clock frequency to read out
serial data
>0
tDOactive
tDOtristate
ns
1
MHz
Pulse Width Modulation Output
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
20
μs
fPWM
Programming Conditions
tPROG
Programming time per bit
Time to prog. a single fuse bit
10
Refresh time per bit
Time to charge the cap after
tPROG
1
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
tCHARGE
ams Datasheet
[v2-00] 2016-Feb-05
μs
Page 13
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AS5145H/AS5145A/AS5145B − Detailed Description
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
Page 14
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ams Datasheet
[v2-00] 2016-Feb-05
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
Slow Mode
(Mode = Low or Open)
Fast Mode
(Mode = High, VDD= 5V)
2.61 kHz (384 μs)
10.42 kHz (96μs)
≤ 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
Parameter
Sampling rate
Transition noise (1 sigma)
Note(s):
1. A change of the Mode during operation is not allowed. The setup must be constant during power up and during operation.
ams Datasheet
[v2-00] 2016-Feb-05
Page 15
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AS5145H/AS5145A/AS5145B − Detailed Description
Synchronous Serial Interface (SSI)
Figure 13:
Synchronous Serial Interface with Absolute Angular Position Data
TCLK/2
CSn
tCSn
tCLK FE
1
CLK
D11
DO
D10 D9
D8
D7
D6
D5
1
18
8
D4
D3
D2
D1
D0
OCF COF
LIN
tCLK FE
Mag Mag Even
INC DEC PAR
D11
tDO valid
tDO active
Angular Position Data
Status Bits
tDO Tristate
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 t CSn.
Data Content
D11:D0 absolute angular position data (MSB is clocked out first)
OCF (Offset Compensation Finished), logic high indicates the
finished Offset Compensation Algorithm
COF (CORDIC Overflow), logic high indicates an out of range
error in the CORDIC part. When this bit is set, the data at D11:D0
is invalid. The absolute output maintains the last valid angular
value.
This alarm can be resolved by bringing the magnet within the
X-Y-Z tolerance limits.
LIN (Linearity Alarm), logic high indicates that the input field
generates a critical output linearity.
When this bit is set, the data at D11:D0 can still be used, but can
contain invalid data. This warning can be resolved by 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.
Page 16
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ams Datasheet
[v2-00] 2016-Feb-05
AS5145H/AS5145A/AS5145B − Detailed Description
Data D11:D0 is valid, when the status bits have the following
configurations:
Figure 14:
Status Bit Options
OCF
COF
1
LIN
0
Mag INC
Mag DEC
0
0
0
1
1
0
1
1
0
Parity
Even checksum
of bits 1:15
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
Hardware
Pins
Status Bits
OTP: Mag CompEn = 1 (Red-Yellow-Green)
Mac
INC
Mag
DEC
LIN
Mac
INCn
Mag
DECn
0
0
0
Off
Off
No distance change
Magnetic input field OK (GREEN range, ~45mT to 75mT)
1
1
0
On
Off
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
Description
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.
ams Datasheet
[v2-00] 2016-Feb-05
Page 17
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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
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).
0
0
0
1
10-bit
Incremental
mode
(low DNL)
12-bit
Incremental
mode
(high DNL)
Sync mode
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.
In this mode a control
signal is switched to
DTEST1_A and
DTEST2_B.
Page 18
Document Feedback
Output
Md0
Resolution
DTest1_A
and
DTest2_B
Pulses
10
256
Index
Width
1/3
LSB
1
0
1
1
12
1024
ams Datasheet
[v2-00] 2016-Feb-05
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 ( R ext ≤ 5kΩ ). 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
ClockWise
Programmed
Zero Position
Counter ClockWise
D Test1_A
D Test2_B
1 LSB
Mode_Index
3 LSB
The hysteresis trimming is done at the final test (factory
trimming) and set to 4 LSB, related to a 12-bit number.
ams Datasheet
[v2-00] 2016-Feb-05
Page 19
Document Feedback
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
Indication
Hysteresis :
0.35°
X +6
X +5
X +4
X +3
X +2
X +1
X
X
X +1 X +2 X +3 X +4 X +5 X +6
Magnet Position
Clockwise Direction
Counterclockwise Direction
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.
Page 20
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ams Datasheet
[v2-00] 2016-Feb-05
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
400µs (100µs)
DTest1_A
DTest1_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.
ams Datasheet
[v2-00] 2016-Feb-05
Page 21
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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
AS5145
2nd Device
AS5145
1st Device
µC
Data IN
PDIO
DO
DO
PDIO
CSn
CLK
CSn
AS5145
last Device
DO
CLK
PDIO
CSn
CLK
CLK
CSn
Figure 21:
Daisy Chain Mode Data Transfer
CSn
tCLK FE
TCLK/2
1
CLK
D11
DO
tDO active
tDO valid
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
OCF COF
LIN
Mag Mag Even
INC DEC PAR
Status Bits
Angular Position Data
1st Device
Page 22
Document Feedback
D
18
8
1
2
3
D11
D10
D9
Angular Position Data
2nd Device
ams Datasheet
[v2-00] 2016-Feb-05
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
(EQ1)
t ⋅ 4098
( t on + t off )
on
-–1
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
Angle
PWMIN
0 deg
(Pos 0)
1µs
4098µs
PWMAX
359.91 deg
(Pos 4095)
4097µs
1/fPWM
ams Datasheet
[v2-00] 2016-Feb-05
Page 23
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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)
Symbol
Parameter
Typ
Unit
Note
fPWM
PWM frequency
244
Hz
PWMIN
MIN pulse width
1
μs
• Position 0d
• Angle 0 deg
PWMAX
MAX pulse width
4097
μs
• Position 4095d
• Angle 359.91 deg
Signal period: 4097μs
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
fPWM
PWM frequency
122
Hz
PWMIN
MIN pulse width
2
μs
• Position 0d
• Angle 0 deg
PWMAX
MAX pulse width
8194
μs
• Position 4095d
• Angle 359.91 deg
Page 24
Document Feedback
Note
Signal period: 8194μs
ams Datasheet
[v2-00] 2016-Feb-05
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
Pin12
R2
R1
analog out
PWM
VDD
C1
C2
0V
Pin7
0º
360º
VSS
Figure 25 shows an example of a simple passive low pass filter
to generate the analog output.
(EQ2)
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.
ams Datasheet
[v2-00] 2016-Feb-05
Page 25
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AS5145H/AS5145A/AS5145B − Application Information
Application Information
The benefits of AS5145 are as follows:
• Complete system-on-chip
• Flexible system solution provides absolute and PWM
outputs simultaneously
• Ideal for applications in harsh environments due to
contactless position sensing
• No calibration required
• No temperature compensation necessary
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.
Page 26
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ams Datasheet
[v2-00] 2016-Feb-05
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.
ams Datasheet
[v2-00] 2016-Feb-05
Page 27
Document Feedback
AS5145H/AS5145A/AS5145B − Application Information
OTP Memory Assignment
Symbol
Function
mbit1
Factory Bit 1
51
PWMhalfEN_Index width
PMW frequency Index pulse
width
50
MagCompEn
Alarm mode (programmed by
ams to 1)
49
pwmDIS
Disable PWM
48
Output Md0
47
Output Md1
46
Z0
:
:
35
Z11
34
CCW
33
RA0
:
:
29
RA4
28
FS 0
27
FS 1
26
FS 2
25
FS 3
24
FS 4
23
FS 5
:
:
20
FS 8
19
FS 9
18
FS 10
Default, 10-bit inc, 12-bit inc
Sync mode
12-bit Zero Position
Direction
Redundancy Address
Factory Bit
Page 28
Document Feedback
Factory Section
Bit
Customer Section
Figure 26:
OTP Bit Assignment
ams Datasheet
[v2-00] 2016-Feb-05
AS5145H/AS5145A/AS5145B − Application Information
Symbol
17
ChipID0
16
ChipID1
:
:
0
ChipID17
Function
ID Section
Bit
18-bit Chip ID
mbit0
Factory Bit 0
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
ams Datasheet
[v2-00] 2016-Feb-05
Page 29
Document Feedback
AS5145H/AS5145A/AS5145B − Application Information
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.
0
0
00001
1
0
0
00010
0
1
00011
0
00100
Z0
Z1
Z2
Z3
Z4
Z5
Z6
Z7
Z8
Z9
Z10
Z11
CCW
pwmDIS
0
Output Md1
MagCompEN
00000
Output Md0
Address
PWMhalfEN_Indexwidth
Figure 27:
Redundancy Addressing
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
00101
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
00110
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
00111
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
01000
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
01001
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
01010
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
01011
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
01100
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
01101
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
01110
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
01111
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
10000
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
10001
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
10010
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
10101
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
Page 30
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ams Datasheet
[v2-00] 2016-Feb-05
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
OTP Access
Setup Condition
CSn
PDIO
CLK
Operation Mode Selection
Exit Condition
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.
ams Datasheet
[v2-00] 2016-Feb-05
Page 31
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AS5145H/AS5145A/AS5145B − Application Information
Figure 29:
OTP Programming Connection
AS5145 Demoboard
1
MagINCn
2 MagDECn
3
VDD5V 16
VDD3V3 15
6
7
8
10n
NC
Mode_ Index
3V3
NC 14
13
NC
DTest 1_A
4 DTest2_B
5
PWM
CSn
VSS
CLK
PDIO
DO
AS 5 1 4 5
USB
For programming,
k eep these 6 wires
as short as possible!
max. length = 2 inches (5cm)
IC 1
7
6
5
4
3
2
1
12
11
10
9
2.2µF
22k
PROG
CSN
DO
CLK
5 VUSB
VDD3V3
VSS
µC
GND
connect to USB
interface on PC
3 VPROG
2
+
1
10µF
VSS
GND
3.3 … 4. 6 V
only required for
OTP programming
Cap only required for OTP programming
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.
Page 32
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ams Datasheet
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AS5145H/AS5145A/AS5145B − Application Information
Figure 30:
Enabling the Alignment Mode
PDIO
CSn
2µs
min.
AlignMode enable
Read-out
via SSI
exit AlignMode
Read-out
via SSI
2µs
min.
Figure 31:
Exiting Alignment Mode
PDIO
CSn
ams Datasheet
[v2-00] 2016-Feb-05
Page 33
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AS5145H/AS5145A/AS5145B − Application Information
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
5V Operation
3.3V Operation
2.2 ... 10µF
VDD3V3
VDD3V3
100nF
VDD5V
100nF
LDO
Internal
VDD
VDD5V
LDO
Internal
VDD
DO
DO
PWM
4.5 - 5.5V
VSS
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I
N
T
E
R
F
A
C
E
CLK
CSn
+
-
-
+
3.0 - 3.6V
PDIO
VSS
I
N
T
E
R
F
A
C
E
PWM
CLK
CSn
PDIO
ams Datasheet
[v2-00] 2016-Feb-05
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
typ. 6mm diameter
N
S
Magnet axis
R1
Magnet axis
Vertical field
component
R1 concentric circle;
radius 1.1mm
Vertical field
component
Bv
(45…75mT)
0
360
360
ams Datasheet
[v2-00] 2016-Feb-05
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AS5145H/AS5145A/AS5145B − Application Information
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
3.9mm
3.9mm
2.4325mm
1
Defined
center
2.4325mm
Rd
Area of recommended maximum magnet misalignment
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).
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ams Datasheet
[v2-00] 2016-Feb-05
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.
ams Datasheet
[v2-00] 2016-Feb-05
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AS5145H/AS5145A/AS5145B − Application Information
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
6
5
4
° 3
800
500
2
200
1
-100
-700
-1000
-1000
-800
-400
-600
-200
0
200
600
y
Page 38
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x
-400
400
1000
800
0
ams Datasheet
[v2-00] 2016-Feb-05
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
0.5
0.4
0.3
0.2
transition noise
0.1
Err max
0
-0.1
1
55
109
163
217
271
325
379
433
487
541
595
649
703
757
811
865
919
973
Err min
-0.2
-0.3
-0.4
-0.5
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.
ams Datasheet
[v2-00] 2016-Feb-05
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AS5145H/AS5145A/AS5145B − Application Information
• 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
(EQ3)
nslowmode =
60
---------------------------------rpm ⋅ ( 384 )μs
(EQ4)
nfastmode =
60 -------------------------rmp ⋅ 96μs
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).
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ams Datasheet
[v2-00] 2016-Feb-05
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:
(EQ5)
e sampling = 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 T on 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
T off and calculating the angle from the duty cycle (see
Pulse Width Modulation (PWM) Output)
(EQ6)
ams Datasheet
[v2-00] 2016-Feb-05
t ⋅ 4097
( t on + t off )
on
-–1
Position = -------------------------
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AS5145H/AS5145A/AS5145B − Application Information
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.
Page 42
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ams Datasheet
[v2-00] 2016-Feb-05
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)
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)
ams Datasheet
[v2-00] 2016-Feb-05
Pre-defined to Fast mode
12-Bit angle
Page 43
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AS5145H/AS5145A/AS5145B − Package Drawings & Markings
Package Drawings & Markings
The device is available in SSOP 16 (5.3mm x 6.2mm).
Figure 38:
Package Drawings and Dimensions
Symbol
Min
Nom
Max
A
A1
A2
b
c
D
E
E1
e
L
L1
L2
R
Q
N
1.73
0.05
1.68
0.22
0.09
5.90
7.40
5.00
0.55
0.09
0º
1.86
0.13
1.73
0.315
0.17
6.20
7.80
5.30
0.65 BSC
0.75
1.25 REF
0.25 BSC
4º
16
1.99
0.21
1.78
0.38
0.25
6.50
8.20
5.60
0.95
8º
RoHS
Green
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
M
ZZ
@
Manufacturing year
Manufacturing week
Plant identifier
Assembly traceability code
Sublot identifier
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ams Datasheet
[v2-00] 2016-Feb-05
AS5145H/AS5145A/AS5145B − Package Drawings & Markings
Figure 40:
Vertical Cross Section of SSOP-16
Note(s):
1. All dimensions in mm.
ams Datasheet
[v2-00] 2016-Feb-05
Page 45
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AS5145H/AS5145A/AS5145B − Package Drawings & Markings
Recommended PCB Footprint
Figure 41:
PCB Footprint
Recommended
Footprint Data
Symbol
mm
A
B
C
D
E
Page 46
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9.02
6.16
0.46
0.65
5.01
ams Datasheet
[v2-00] 2016-Feb-05
AS5145H/AS5145A/AS5145B − Ordering & Contact Information
Ordering & Contact Information
The devices are available as the standard products shown in
Figure 42.
Figure 42:
Ordering Information
Ordering Code
AS5145H-HSST
AS5145H-HSSM
AS5145A-HSST
AS5145A-HSSM
AS5145B-HSST
AS5145B-HSSM
Description
Package
Delivery
Quantity
2000 pcs/reel
12-Bit Programmable
Magnetic Rotary Encoder
Pre-programmed 10-bit
incremental
Delivery
Form
Tape & Reel
500 pcs/reel
SSOP 16
(5.3mm x 6.2mm)
Pre-programmed 12-bit
incremental
2000 pcs/reel
Tape & Reel
500 pcs/reel
2000 pcs/reel
Tape & Reel
500 pcs/reel
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:
[email protected]
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
ams Datasheet
[v2-00] 2016-Feb-05
Page 47
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AS5145H/AS5145A/AS5145B − RoHS Compliant & ams Green Statement
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.
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ams Datasheet
[v2-00] 2016-Feb-05
AS5145H/AS5145A/AS5145B − Copyrights & Disclaimer
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.
ams Datasheet
[v2-00] 2016-Feb-05
Page 49
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AS5145H/AS5145A/AS5145B − Document Status
Document Status
Document Status
Product Preview
Preliminary Datasheet
Datasheet
Datasheet (discontinued)
Page 50
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Product Status
Definition
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
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
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
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
ams Datasheet
[v2-00] 2016-Feb-05
AS5145H/AS5145A/AS5145B − Revision Information
Revision Information
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
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.
ams Datasheet
[v2-00] 2016-Feb-05
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AS5145H/AS5145A/AS5145B − Content Guide
Content Guide
Page 52
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1
1
2
2
General Description
Key Benefits & Features
Applications
Block Diagram
3
3
Pin Assignment
Pin Description
6
Absolute Maximum Ratings
7
10
11
Electrical Characteristics
Magnetic Input Specification
System Specifications
13
Timing Characteristics
14
15
16
18
21
21
22
23
24
25
Detailed Description
Mode_Index Pin
Synchronous Serial Interface (SSI)
Incremental Mode
Sync Mode
Sin/Cosine Mode
Daisy Chain Mode
Pulse Width Modulation (PWM) Output
Changing the PWM Frequency
Analog Output
26
26
27
28
29
29
30
31
31
32
34
35
36
36
37
37
37
38
38
39
40
41
41
42
42
43
Application Information
Programming the AS5145
Zero Position Programming
OTP Memory Assignment
User Selectable Settings
OTP Default Setting
Redundancy
Redundant Programming Option
OTP Register Entry and Exit Condition
Alignment Mode
3.3V / 5V Operation
Selecting Proper Magnet
Physical Placement of the Magnet
Magnet Placement
Failure Diagnostics
Magnetic Field Strength Diagnosis
Power Supply Failure Detection
Angular Output Tolerances
Accuracy
Transition Noise
High Speed Operation
Propagation Delays
Internal Timing Tolerance
Temperature
Accuracy Over Temperature
Differences Between AS5145H, AS5145A and AS5145B
ams Datasheet
[v2-00] 2016-Feb-05
AS5145H/AS5145A/AS5145B − Content Guide
ams Datasheet
[v2-00] 2016-Feb-05
44
46
Package Drawings & Markings
Recommended PCB Footprint
47
48
49
50
51
Ordering & Contact Information
RoHS Compliant & ams Green Statement
Copyrights & Disclaimer
Document Status
Revision Information
Page 53
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