AMSCO AS5046_1

AS5046
PROGRAMMABLE 12-bit 360° MAGNETIC ANGLE ENCODER
WITH ABSOLUTE 2-WIRE SERIAL AND ANALOG INTERFACES
1
General Description
2
The AS5046 is a contactless magnetic angle encoder for
accurate measurement up to 360°.
It is a system-on-chip, combining integrated Hall
elements, analog front end and digital signal processing
in a single device.
The AS5046 provides a digital serial 12-bit as well as a
programmable 10-bit ratiometric analog output that is
directly proportional to the angle of a magnet, rotating
over the chip.
In addition, the serial interface enables a user
configurable arrangement of the Hall array and allows
access to each individual Sensor of the Hall Array.
The AS5046 also provides high resolution information of
the magnetic field strength, respectively the vertical
distance of the magnet, thus adding excellent state-ofhealth information of the overall system.
An internal voltage regulator allows operation of the
AS5046 from 3.3V or 5.0V supplies.
PRELIMINARY DATA SHEET
Key Features
•
360° contactless high resolution angular position encoding
•
User programmable zero position
•
12-bit 2-wire serial interface
•
Versatile analog output
programmable angular range up to 360°
programmable ratiometric output voltage range
•
High resolution magnet distance indication
256 steps within recommended range (~0.5 to 1.8mm)
256 steps over extended range (~0 to 5mm)
•
Mode input for optimizing noise vs. speed
•
Alignment mode for magnet placement guidance
•
Wide temperature range: - 40°C to + 125°C
•
Small package: SSOP 16 (5.3mm x 6.2mm)
3
Applications
The AS5046 is ideal for applications that require high
resolution, a minimum of wires between controller and
sensor and where the vertical distance of the magnet is
of importance:
•
Remote sensors
•
Rotate-and-push manual input devices
•
Joysticks
•
Applications with extended safety requirements
regarding magnet distance
MagRNGn
Figure 1: Typical arrangement of AS5046 and magnet
Hall Array
&
Frontend
Amplifier
Benefits
•
Complete system-on-chip
•
High reliability due to non-contact sensing
•
Bi-directional 2-wire interface
•
Ideal for application s in harsh environments
•
Robust system, tolerant to magnet misalignment,
airgap variations, temperature variations and
external magnetic fields
Revision 1.1
Ang
DSP
14-bit
ADC
Cos
Mag
Hall
Sensor
switch
matrix
CSn
12
Absolute
Interface
(I²C)
8
12
SDA
8
SCL
12
8
DACref
FB
12
OTP
Register
Programmable ratiometric analog output
No calibration required
Sin
AGC
•
•
Mode
14-bit
ADC
Range
preselect
Vout
AS5046
10
Programming
Parameters
10bit
DAC
+
DACout
Prog_DI
Figure 2: AS5046 block diagram
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Page 1 of 33
AS5046 Programmable 360° Magnetic Angle Encoder – Preliminary Data Sheet
4
Pin Configuration
MagRngn
1
16
VDD5V
Mode
2
15
VDD3V3
CSn
3
14
NC
SCL
4
13
NC
NC
5
12
Vout
SDA
6
11
FB
VSS
7
10
DACout
Prog
8
9
DACref
Figure 3: AS5046 pin configuration SSOP16
Package = SSOP16 (16 lead Shrink Small Outline Package)
Pin
Symbol
Type
Description
1
MagRngn
DO_OD
Magnet Field Magnitude RaNGe warning;
active low, indicates that the magnetic
field strength is outside of the
recommended limits.
2
Mode
DI_PD,
ST
Mode input. Select between low noise
(open, low) and high speed (high) mode.
Internal pull-down resistor
3
CSn
DI_PU,
ST
Chip Select, active low; Schmitt-Trigger
input, internal pull-up resistor (~50kΩ).
Must be connected to VSS for serial data
transmission.
4
SCL
DI,ST
Serial Clock Line.Clock input for 2-wire
serial data transmission
5
NC
-
must be left unconnected
6
SDA
DIO
Serial Data Line. Bi-directional I/O for 2wire serial data transmission
7
VSS
S
Negative Supply Voltage (GND)
8
Prog
DI_PD
OTP Programming Input.
Internal pull-down resistor (~74kΩ).
Should be connected to VSS if
programming is not used
9
DACref
AI
DAC Reference voltage input for external
reference
10
DACout
AO
DAC output (unbuffered, Ri ~8kΩ)
11
FB
AI
Feedback, OPAMP inverting input
12
Vout
AO
OPAMP output
13
NC
-
Must be left unconnected
14
NC
-
Must be left unconnected
15
VDD3V3
S
3V-Regulator Output for internal core,
regulated from VDD5V.Connect to
VDD5V for 3V supply voltage. Do not
load externally.
16
VDD5V
S
Positive Supply Voltage, 3.0 to 5.5 V
DO_OD
DI_PD
DI_PU
AI
DI
4.1
digital output open drain
digital input pull-down
digital input pull-up
analog input
S
supply pin
DO_T digital output /tri-state
ST schmitt-trigger input
AO analog output
digital input
Pin Description
Pins 7, 15 and 16 are supply pins, pins 5, 13 and 14 are
for internal use and must be left open.
Pin 1 is the magnetic field strength indicator, MagRNGn.
It is an open-drain output that is pulled to VSS when the
magnetic field is out of the recommended range (45mT to
75mT). The chip will still continue to operate, but with
reduced performance, when the magnetic field is out of
range. When this pin is low, the analog output at pins
#10 and #12 will be 0V to indicate the out-of-range
condition.
Pin 2 MODE allows switching between filtered (slow) and
unfiltered (fast mode). See section 10.
Pin 3 Chip Select (CSn; active low) selects a device for
serial data transmission over the 2-wire interface. A
“logic high” at CSn forces output SDA to digital tri-state.
Pin 4 SCL (Serial Clock) is the clock input for data
transmission over the 2-wire serial interface
Pin 6 SDA (Serial Data Line) is the serial data input /
output line during data transmission over the 2-wire
interface
Pin 8 PROG is used to program the different operation
modes, as well as the zero-position in the OTP register.
Pin 9 DACref is the external voltage reference input for
the Digital-to-Analog Converter (DAC). If selected, the
analog output voltage on pin 12 (V out ) will be ratiometric
to the voltage on this pin.
Pin10 DACout is the unbuffered output of the DAC. This
pin may be used to connect an external OPAMP, etc. to
the DAC.
Pin 11 FB (Feedback) is the inverting input of the
OPAMP buffer stage.
Access to this pin allows various OPAMP configurations.
Pin 12 Vout is the analog output pin. The analog output
is a DC voltage, ratiometric to VDD5V (3.0 – 5.5V) or an
external voltage source and proportional to the angle.
Table 1: Pin description SSOP16
Revision 1.1
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Page 2 of 33
AS5046 Programmable 360° Magnetic Angle Encoder – Preliminary Data Sheet
5
Electrical Characteristics
5.1
Absolute Maximum Ratings (non operating)
Stresses beyond those listed under “Absolute Maximum Ratings“ may cause permanent damage to the device. These are
stress ratings only. Functional operation of the device at these or any other conditions beyond those indicated under
“Operating Conditions” is not implied. Exposure to absolute maximum rating conditions for extended periods may affect
device reliability.
Parameter
DC supply voltage
Input pin voltage
Symbol
Min
Max
Unit
Note
VDD5V
-0.3
7
V
Pin VDD5V
5
V
Pin VDD3V3
VDD3V3
Vin
Input current (latchup immunity)
Iscr
Electrostatic discharge
ESD
Storage temperature
Tstrg
Body temperature (Lead-free package)
TBody
Humidity non-condensing
H
5.2
Pins MagRngn, Mode, CSn, CLK, DO, DACout, FB,
Vout
-0.3
VDD5V +0.3
-0.3
5
-0.3
7.5
-100
100
mA
Norm: JEDEC 78
±2
kV
Norm: MIL 883 E method 3015
125
°C
Min – 67°F ; Max +257°F
260
°C
85
%
-55
5
V
Pin DACref
Pin PROG_DI
t=20 to 40s, Norm: IPC/JEDEC J-Std-020C
Lead finish 100% Sn “matte tin”
Operating Conditions
Parameter
Symbol
Min
Ambient temperature
Tamb
-40
Supply current
Isupp
Supply voltage at pin VDD5V
VDD5V
Voltage regulator output voltage at pin VDD3V3
VDD3V3
Supply voltage at pin VDD5V
Supply voltage at pin VDD3V3
Revision 1.1
Typ
Max
Unit
Note
125
°C
-40°F…+257°F
16
21
mA
4.5
5.0
5.5
V
3.0
3.3
3.6
V
VDD5V
3.0
3.3
3.6
V
VDD3V3
3.0
3.3
3.6
V
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5V operation
3.3V operation
(pin VDD5V and VDD3V3 connected)
Page 3 of 33
AS5046 Programmable 360° Magnetic Angle Encoder – Preliminary Data Sheet
5.3
5.3.1
DC Characteristics for Digital Inputs and Outputs
CMOS Schmitt-Trigger Inputs: SCL, CSn (internal Pull-up), Mode (internal Pull-down)
(operating conditions: Tamb = -40 to +125°C, VDD5V = 3.0-3.6V (3V operation) VDD5V = 4.5-5.5V (5V operation) unless otherwise noted)
Parameter
Symbol
Min
High level input voltage
VIH
0.7 * VDD5V
Low level input voltage
VIL
Schmitt Trigger hysteresis
VIon- VIoff
1
Input leakage current
ILEAK
-1
1
Pull-up low level input current
IiL
-30
-100
Pull-down high level input current
IiH
30
100
5.3.2
Max
0.3 * VDD5V
Unit
Note
V
Normal operation
V
V
Pin CLK, VDD5V = 5.0V
µA
Pin CSn, VDD5V= 5.0V
Pin Mode, VDD5V= 5.0V
CMOS Input: Program Input (Prog)
(operating conditions: T amb = -40 to +125°C, VDD5V = 3.0-3.6V (3V operation) VDD5V = 4.5-5.5V (5V operation) unless
otherwise noted)
Parameter
Symbol
Min
Max
Unit
High level input voltage
VIH
0.7 * VDD5V
5
V
High level input voltage
VPROG
See “programming conditions”
Low level input voltage
VIL
0.3 * VDD5V
V
Pull-down high level input current
IiL
100
µA
5.3.3
V
Note
During programming
VDD5V: 5.5V
CMOS Output Open Drain: MagRngn
(operating conditions: T amb = -40 to +125°C, VDD5V = 3.0-3.6V (3V operation) VDD5V = 4.5-5.5V (5V operation) unless
otherwise noted)
Parameter
Symbol
Low level output voltage
VOL
Output current
IO
Open drain leakage current
IOZ
5.3.4
Min
Max
Unit
VSS+0.4
V
4
2
1
mA
Note
VDD5V: 4.5V
VDD5V: 3V
µA
Tristate CMOS Output: SDA
(operating conditions: Tamb = -40 to +125°C, VDD5V = 3.0-3.6V (3V operation) VDD5V = 4.5-5.5V (5V operation) unless otherwise noted)
Parameter
Symbol
Min
High level output voltage
VOH
VDD5V –0.5
Low level output voltage
VOL
VSS+0.4
V
Output current
IO
4
mA
VDD5V: 4.5V
2
mA
VDD5V: 3V
1
µA
Tri-state leakage current
Revision 1.1
IOZ
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Max
Unit
Note
V
Page 4 of 33
AS5046 Programmable 360° Magnetic Angle Encoder – Preliminary Data Sheet
5.3.5
Digital-to-Analog Converter
Parameter
Symbol
Min
Typ
Resolution
Max
Unit
Output Range
Output resistance
DAC reference voltage
(DAC full scale range)
OTP setting
VOUTM1
0
Vref
V
0……100% Vref (default)
ClampMdEn = 0 (default)
VOUTM2
0.10 *Vref
0.90 *Vref
V
10…..90% Vref
ClampMdEn = 1
8
kΩ
Unbuffered Pin DACout (#10)
VDD3V3 - 0.2
V
DAC reference = external:
Pin: DACref (#9)
RefExt EN = 1
VDD5V / 2
V
DAC reference = internal
RefExtEn = 0 (default)
Non-Linearity of DAC and
OPAMP; -40….+125°C, For all
analog modes:
1LSB = Vref / 1024
ROut,DAC
0.2
Vref
Integral Non-Linearity
INLDAC
+/- 1.5
LSB
Differential Non-Linearity
DNLDAC
+/- 0.5
LSB
1
LSB
Analog output hysteresis
Hyst
2
LSB
5.3.6
Note
bit
10
All analog modes
At 360°-0° transition,
360° mode only
OR1,OR0 = 00 (default)
OPAMP Output Stage
Parameter
Power Supply Range
Symbol
VDD5V
Min
Typ
Parallel Load Capacitance
CL
Parallel Load Resistance
RL
4.7
Open Loop Gain
A0
92
VosOP
-5
Offset Voltage RTI
Max
3.0
Unit
5.5
V
100
pF
kΩ
130
144
dB
5
mV
3.3V operation
3 sigma
Output Range Low
VoutL
Output Range High
VoutH
0.95 * VDD5V
Isink
4.8
50
mA
Permanent short
V out to VDD5V
circuit
current:
Isource
4.6
66
mA
Permanent short
V out to VSS
circuit
current:
V noi se
160
490
µVrms
Over full temperature range;
BW= 1Hz…10MHz,Gain = 2x
current capability sink
current capability source
Output noise
0.05 * VDD5V V
Note
V
220
2
OPAMP gain (non-inverting)
Gain
1
Linear range of analog output
Internal; OTP: FB_int EN = 1
4
External OTP: FB_int EN = 0
(default)
With external resistors, pins Vout
[#12] and FB [#11]: see Figure 17
Revision 1.1
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Page 5 of 33
AS5046 Programmable 360° Magnetic Angle Encoder – Preliminary Data Sheet
5.4
Magnetic Input Specification
(operating conditions: T amb = -40 to +125°C, VDD5V = 3.0-3.6V (3V operation) VDD5V = 4.5-5.5V (5V operation)
unless otherwise noted)
Two-pole cylindrical diametrically magnetised source:
Parameter
Symbol
Min
Typ
Diameter
dmag
4
Thickness
tmag
2.5
Magnetic input field amplitude
Bpk
45
Magnetic offset
Boff
Max
6
mm
mm
(rotational speed of magnet)
Displacement radius
Recommended magnet: Ø 6mm x 2.5mm for cylindrical
magnets
mT
Required vertical component of the magnetic field strength on
the die’s surface, measured along a concentric circle with a
radius of 1.1mm
± 10
mT
Constant magnetic stray field
5
%
Including offset gradient
fmag_abs
10
Hz
fmag_inc
166
Hz
Incremental mode: no missing pulses at rotational speeds of
up to 10,000 rpm (see table 6)
Disp
0.25
mm
Max. offset between defined device center and magnet axis
-0.12
Recommended magnet material
and temperature drift
5.5
Note
75
Field non-linearity
Input frequency
Unit
%/K
-0.035
Absolute mode: 600 rpm @ readout of 1024 positions
(see table 6)
NdFeB (Neodymium Iron Boron)
SmCo (Samarium Cobalt)
Electrical System Specifications
(operating conditions: T amb = -40 to +125°C, VDD5V = 3.0-3.6V (3V operation) VDD5V = 4.5-5.5V (5V operation)
unless otherwise noted)
Parameter
Symbol
Resolution 1)
Min
Typ
Max
Unit
Note
RES
12
bit
0.088 deg
Integral non-linearity (optimum) 1)
INLopt
± 0.5
deg
Maximum error with respect to the best line fit.
Verified at optimum magnet placement, Tamb =25 °C.
Integral non-linearity (optimum) 1)
INLtemp
± 0.9
deg
Maximum error with respect to the best line fit.
Verified at optimum magnet placement ,
Tamb = -40 to +125°C
Integral non-linearity 1)
INL
± 1.4
deg
Over displacement tolerance with 6mm diameter magnet,
Tamb = -40 to +125°C
Differential non-linearity 1)
DNL
± 0.044
deg
12bit, no missing codes
Transition noise 1)
TN
0.06
1 sigma, fast mode (pin MODE = 1)
0.03
Deg
RMS
Best line fit = (Errmax – Errmin) / 2
Power-on reset thresholds
On voltage; 300mV typ. hysteresis
Von
1.37
2.2
2.9
V
Off voltage; 300mV typ. hysteresis
Voff
1.08
1.9
2.6
V
Power-up time,
Until offset compensation finished,
OCF = 1, Angular Data valid
System
propagation
delay
absolute output : delay of ADC and
DSP
Revision 1.1
20
DC supply voltage 3.3V (VDD3V3)
DC supply voltage 3.3V (VDD3V3)
fast mode (pin MODE=1)
ms
tPwrUp
80
slow mode (pin MODE=0 or open)
96
tdelay
1 sigma, slow mode (pin MODE=0 or open)
384
fast mode (pin MODE=1)
µs
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slow mode (pin MODE=0 or open)
Page 6 of 33
AS5046 Programmable 360° Magnetic Angle Encoder – Preliminary Data Sheet
Parameter
Symbol
Internal sampling rate for absolute
output
fS,mode0
Internal sampling rate for absolute
output
fS,mode1
Read-out frequency
CLK
Min
Typ
Max
2.48
2.61
2.74
2.35
2.61
2.87
9.90
10.42
10.94
9.38
10.42
11.46
>0
1
Unit
kHz
kHz
MHz
Note
Tamb = 25°C, slow mode (pin MODE=0 or open)
Tamb = -40 to +125°C, slow mode (pin MODE=0 or open)
Tamb = 25°C, fast mode (pin MODE = 1)
Tamb = -40 to +125°C, : fast mode (pin MODE = 1)
Max. clock frequency to read out serial data
Note: 1) digital interface
4095 α 12bit code
4095
Actual curve
TN
2
DNL+1LSB
1
Ideal curve
INL
0.09°
0
2048
2048
0
360 °
180°
0°
α [degrees]
Figure 4: Integral and differential non-linearity (exaggerated curve)
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.
5.6
Timing Characteristics
2-wire Serial Interface
(operating conditions: T amb = -40 to +125°C, VDD5V = 3.0-3.6V (3V operation) VDD5V = 4.5-5.5V (5V operation) unless
otherwise noted)
Parameter
Symbol
Data output activated (logic high)
t DO active
First data shifted to output register
tCLK FE
Start of data output
Max
Unit
Note
100
ns
Time between falling edge of CSn and data output activated
500
ns
Time between falling edge of CSn and first falling edge of
CLK
T CLK / 2
500
ns
Rising edge of CLK shifts out one bit at a time
Data output valid
t DO valid
357
394
ns
Time between rising edge of CLK and data output valid
Data output tristate
t DO tristate
100
ns
After the last bit DO changes back to “tristate”
Pulse width of CSn
t CSn
500
ns
CSn = high; To initiate read-out of next angular position
Read-out frequency
fCLK
>0
MHz
Clock frequency to read out serial data
Revision 1.1
Min
Typ
375
1
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Page 7 of 33
AS5046 Programmable 360° Magnetic Angle Encoder – Preliminary Data Sheet
5.7
Programming Conditions
(operating conditions: T amb = -40 to +125°C, VDD5V = 3.0-3.6V (3V operation) VDD5V = 4.5-5.5V (5V operation) unless
otherwise noted)
Parameter
Symbol
Min
Programming enable time
t Prog enable
2
µs
Write data start
t Data in
2
µs
Write data valid
t Data in valid
250
ns
Load programming data
t Load PROG
3
µs
Rise time of VPROG before CLK PROG
t PrgR
0
µs
Hold time of VPROG after CLK PROG
t PrgH
0
Max
Unit
Note
Time between rising edge at Prog
pin and rising edge of CSn
Write data at the rising edge of
CLKPROG
5
µs
250
kHz
2.2
µs
During programming; 16 clock cycles
µs
Programmed data is available after
next power-on
7.5
V
Must be switched off after zapping
1
V
Line must be discharged to this level
I PROG
130
mA
During programming
Analog read CLK
CLKAread
100
kHz
Analog readback mode
Programmed zener voltage (log.1)
Vprogrammed
100
mV
VRef-VPROG during analog readback
mode (see 13)
Write data – programming CLK PROG
CLK pulse width
CLK PROG
t PROG
1.8
t PROG finished
2
Programming voltage
V PROG
7.3
Programming voltage off level
V ProgOff
0
Hold time
programming
of
Vprog
after
Programming current
Unprogrammed zener voltage (log. 0)
6
Typ
Vunprogrammed
2
7.4
1
V
Functional Description
The AS5046 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 in a circle around the center of the device and deliver a voltage representation of
the magnetic field perpendicular to the surface of the IC.
Through Sigma-Delta Analog / Digital Conversion and Digital Signal-Processing (DSP) algorithms, the AS5046 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 indicate movements of the magnet towards or away from the chip and to indicate, when the magnetic
field is outside of the recommended range (status bits = MagInc, MagDec; hardware pin = MagRngn). In addition, two 8-bit
registers are available that allow determination of the magnetic field strength over a wide range.
A small low cost diametrically magnetized (two-pole) standard magnet, centered over the chip, is used as the input device.
The AS5046 senses the orientation of the magnetic field and calculates a 12-bit binary code. This code can be accessed via
a bi-directional serial two-wire interface. In addition to the digital output, the absolute angle is converted into a 1024-step
(10-bit) analog signal, ratiometric to the supply voltage.
The analog output can be configured in many ways, such as 360°/180°/90° or 45° angular range, external or internal DAC
reference voltage, 0-100%*VDD or 10-90% *VDD analog output range, external or internal amplifier gain setting.
The various output modes as well as a user programmable zero position can be programmed in an OTP register. As long as
no programming voltage is applied to pin PROG, the new setting may be overwritten at any time and will be reset to default
when power is cycled. To make the setting permanent, the OTP register must be programmed by applying a programming
voltage.
Revision 1.1
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Page 8 of 33
AS5046 Programmable 360° Magnetic Angle Encoder – Preliminary Data Sheet
The AS5046 is tolerant to magnet misalignment and unwanted external magnetic fields due to differential measurement
technique and Hall sensor conditioning circuitry.
It is also tolerant to airgap and temperature variations due to Sin-/Cos- signal evaluation.
7
3.3V / 5V Operation
5V Operation
2µ2...10µF
VDD3V3
100n
VDD5V
LDO
Internal
VDD
DO
I
N
T
E
R
F
A
C
E
4.5 - 5.5V
MODE
CLK
CSn
Prog
VSS
For 5V operation, the 5V supply is connected to pin
VDD5V, while VDD3V3 (LDO output) must be buffered by
a 2.2...10µF capacitor, which should be placed close to
the supply pin (see Figure 5).
The VDD3V3 output is intended for internal use only It
should not be loaded with an external load.
The voltage levels of the digital interface I/O’s
correspond to the voltage at pin VDD5V, as the I/O
buffers are supplied from this pin (see Figure 5).
3.3V Operation
VDD3V3
100n
VDD5V
The AS5046 operates either at 3.3V ±10% or at 5V
±10%. This is made possible by an internal 3.3V LowDropout (LDO) Voltage regulator. The core supply
voltage is always taken from the LDO output, as 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 5 ).
LDO
Internal
VDD
A buffer capacitor of 100nF is recommended in both
cases close to pin VDD5V. Note that pin VDD3V3 must
always be buffered by a capacitor. It must not be left
floating, as this may cause an instable internal 3.3V
supply voltage which may lead to larger than normal jitter
of the measured angle.
DO
3.0 - 3.6V
I
N
T
E
R
F
A
C
E
VSS
MODE
CLK
CSn
Prog
Figure 5: Connections for 5V / 3.3V supply voltages
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AS5046 Programmable 360° Magnetic Angle Encoder – Preliminary Data Sheet
8
Two Wire Serial Interface
The AS5046 is accessible via an bi-directional serial interface.
CSn must be low during serial data transmission.
8.1
Serial Interface Timing Diagrams
The registers in the AS5046 are available in a data length of 8 bit (1 byte), 24 bit (3 bytes) and 32 bit (4 bytes).
Shown below in Figure 6 is a common 8-bit data transfer.
Figure 6: 8-bit serial Read / Write timing
Figure 7 shows a transfer timing diagram for the first 16 bits of the Serial Interface Unit.
Figure 7: 16-bit serial Read / Write timing
9
Accessible Registers for Serial Interface
Status Register
Internal
Type
Identifier
Internal
Address
Register
Bit
Count
Read /
Write
Note
10 bit angle <upper 10bits: D11:D2>
Serial Interface Unit
0101
000
Programmable with
A2...A0 1)
6 bit status
32
Read only
8 bit magnitude
2 bit angle <lower 2 bits: D1:D0>
Hall Sensor Front End
0001
000 -111 fixed address range
8
ADC outputs, SIN/COS
0100
signal bus
000
fixed address
24
Automatic Gain Control 0111
000
Fixed address
8
Read / Write
Read / Write
2)
Read / Write
3)
8 selectable Hall front-end status
registers
12bit SIN , 12bit COS input
AGC Counter
Table 2: Serial register overview
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AS5046 Programmable 360° Magnetic Angle Encoder – Preliminary Data Sheet
Notes:
1)
This address is also modified with the analog mode setting
2)
Writing a value to any of the SIN- COS- registers halts the conversion loop and calculates an angle that is given by the
values in the SIN and COS registers. A Read command from these registers restarts the automatic conversion loop.
3)
Writing a value to the AGC counter register halts the automatic gain control loop and sets the AGC to the value written
in this register. The angle conversion loop continues to operate. A Read command from the AGC register restarts the
automatic gain control loop.
9.1
Serial Interface Unit (Type ID: 0101)
The Serial Interface Unit contains 32 bits of data:
Note that the angle information is only valid, if the Hall Sensor Front-end is configured properly. See Table 4 for more
information.
9.1.1
12-bit Angle Information
the 12-bit angle data consists of two blocks: the upper 10-bits in bytes 1 & 2 and the lower two bits in byte 4
9.1.2
6-bit Status Information
Status bit 1
SIU bit 11
Offset Comp Finish
OCF
must be 1 for valid data
Status bit 2
SIU bit 12
CORDIC Over Flow
COF
must be 0; if this bit is set, the
angular data is invalid
Status bit 3
SIU bit 13
Lin Alarm
LIN
LINearity warning bit. Should be 0
for normal operation. Will be 1 when
the magnetic field is too high or too
low
Status bit 4
SIU bit 14
Mag Incr.
M_I
This bit is set temporarily when the
magnetic field increases, when the
magnet is pushed towards the IC
Status bit 5
SIU bit 15
Mag Decr.
M_D
This bit is set temporarily when the
magnetic field decreases, when the
magnet is pulled away from the IC
Status bit 6
SIU bit 16
Even Parity
P
Even parity check bit of bytes 1 & 2
Table 3: Status bits of byte 2 of the SIU
9.1.3
8-bit Magnitude Information
The magnitude information is a value that is proportional to the magnetic field strength. A strong magnet (or close distance
between magnet and chip) will result in a high magnitude value and vice versa. When the automatic gain control (AGC) is
active (default state), it tries to keep the magnitude value stable at a value of 3F H .
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AS5046 Programmable 360° Magnetic Angle Encoder – Preliminary Data Sheet
9.2
Hall Sensor Front End (Type ID: 0001)
The Hall Sensor Front End allows configuration of each Hall Sensor. Each sensor can be disabled or connected to either the
SIN or COS signal bus. Additionally, each sensor can be inverted for differential measurement.
Each Hall Sensor is selected through a device address for the type identifier 0001,
address 000 selects Hall Sensor H0 (see Figure 8)
address 111 selects Hall Sensor H7 (see Figure 8)
Figure 8: Location of Hall Elements on chip (top view)
Note: If the magnet is placed like shown in Figure 8 the encoder reading will be of zero.
For each Hall Sensor, the corresponding Front End contains 8 bits
Type ID: 0001
Addr. 000…111
Byte1
TestEN
SenseEN
NC
NC
COS_EN
SIN_EN
INV
PD
TestEN:
always set to 0
SenseEN:
set to 1 for enabled Hall Elements, set to 0 for disabled Hall Elements
COS_EN:
set to 0 for disabled Hall Elements, set to 1 if this Hall Element should be added to the COS signal bus. It
is also possible to enable multiple Hall sensors to this bus
SIN_EN:
set to 0 for disabled Hall Elements, set to 1 if this Hall Element should be added to the SIN signal bus. It
is also possible to enable multiple Hall sensors to this bus
INV:
set to 1 if the Hall Element should be inverted for differential measurement. set to 0 if the Hall Element
should not be inverted
PD:
set to 0 for normal operation, set to 1 if the Hall Sensor should be powered down.
Note: When enabling or disabling individual Hall elements to the SIN- and COS- signal buses it is recommended
to allow several milliseconds (typ. 5ms) of dwelling time until the signal is stable and eventual offsets are
compensated.
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AS5046 Programmable 360° Magnetic Angle Encoder – Preliminary Data Sheet
9.3
Hall Sensor Front-End Configuration
The default configuration for the Hall Sensor Front-End is set for angle measurement. This configuration must always be
programmed when an angle should be measured and read from the Serial Interface Unit register.
Addr
testEN
SenseEN
NC
NC
COS_EN
SIN_EN
Inv
PD
FE0
000
0
1
0
0
0
1
0
0
FE1
001
0
1
0
0
0
1
0
0
FE2
010
0
1
0
0
1
0
0
0
FE3
011
0
1
0
0
1
0
0
0
FE4
100
0
1
0
0
0
1
1
0
FE5
101
0
1
0
0
0
1
1
0
FE6
110
0
1
0
0
1
0
1
0
FE7
111
0
1
0
0
1
0
1
0
Table 4: Hall Sensor Front-End default configuration
The following configuration example selects Hall Sensor 0 and assigns it to the SIN signal bus:
Addr
testEN
SenseEN
NC
NC
COS_EN
SIN_EN
Inv
PD
FE0
000
0
1
0
0
0
1
0
0
FE1
001
0
0
0
0
0
0
0
0
FE2
010
0
0
0
0
0
0
0
0
FE3
011
0
0
0
0
0
0
0
0
FE4
100
0
0
0
0
0
0
0
0
FE5
101
0
0
0
0
0
0
0
0
FE6
110
0
0
0
0
0
0
0
0
FE7
111
0
0
0
0
0
0
0
0
Table 5: Example: Readout of a single Hall Sensor (Sensor #0)
This example uses two opposite Hall sensors 1 and 5 in differential mode and assigns the resulting signal to the COS signal
bus:
Addr
testEN
SenseEN
NC
NC
COS_EN
SIN_EN
Inv
PD
FE0
000
0
0
0
0
0
0
0
0
FE1
001
0
1
0
0
1
0
0
0
FE2
010
0
0
0
0
0
0
0
0
FE3
011
0
0
0
0
0
0
0
0
FE4
100
0
0
0
0
0
0
0
0
FE5
101
0
1
0
0
1
0
1
0
FE6
110
0
0
0
0
0
0
0
0
FE7
111
0
0
0
0
0
0
0
0
Table 6: Example: Differential measurement of two opposite Hall Sensors (#1 and 5)
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AS5046 Programmable 360° Magnetic Angle Encoder – Preliminary Data Sheet
9.4
Analog-Digital Converter Outputs, SIN/COS Signal Bus (Type ID: 0100)
Byte 1
Byte 2
12-bit ADC output: COS signal bus
12-bit ADC output: SIN signal bus
COS signal bus
SIN signal bus
Upper 8 bits
Upper 8 bits
Lower 4 bits
Lower 4 bits
Type ID:
0100
Addr. 000
11
10
9
8
7
6
5
4
11
10
9
8
7
Byte 3
6
5
4
3
2
1
0
3
2
1
The analog signals on the SIN- and COS- buses are converted into a signed 12-bit digital value by two ADC’s, one for each
bus.
To read the signal from one or more Hall Sensors, first assign a signal bus (SIN, COS) for each Hall Sensor in the Hall
Sensor front-end and then read the corresponding amplitude value from the ADC output register.
Note that the ADC’s are 14-bit (see Block diagram, Figure 2), but only 12-bit are available to the user. The available
12-bit ADC output is again split into an upper 8-bit block (available in bytes 1 & 2) and a lower 4-bit block in byte 3.
The resulting 12-bit value is formatted as a signed 12-bit value and has a range from -2048…+2047 (decimal). Bit 11
(MSB) is the sign bit; if this bit is set, the Sin/Cos value is negative.
9.5
Automatic Gain Control Register (Type ID: 0111)
The Automatic Gain Control is active in the “green” range of the magnetic field, when the magnetic field is within
~35…63mT. If the magnetic field is too low, e.g. when the magnet is too far away from the chip, the AGC register will be
FF H , if the magnetic field is too strong, e.g. when the magnet is too close to the chip, the AGC register will be 00 H . The
Automatic Gain control can be disabled by writing a value into this register. It will be enabled by reading from this register.
The AGC tries to maintain a constant magnitude value of 3F H . If the AGC has reached its upper or lower limit, the magnitude
value can no longer be maintained ad 3F H and will also change accordingly (see 9.1.3 and 9.6).
Type ID: 0111
Addr. 000
Revision 1.1
Byte 1
AGC7
AGC6
AGC5
AGC5
AGC3
AGC2
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AGC1
AGC0
Page 14 of 33
0
AS5046 Programmable 360° Magnetic Angle Encoder – Preliminary Data Sheet
9.6
AGC and Magnitude Registers
The AS5046 allows the readout of two additional registers related to magnetic field strength: magnitude and AGC registers.
Figure 9 shows a graphic example of the interrelations of these two registers in respect to the magnetic field strength of the
magnet (all register levels are in decimal format).
at a low magnetic field strength (below level B1 / B2) the magnitude will be <32 and the AGC will be at maximum: 255. the
LIN status bit will be set (red range). It is not recommended to operate in this range, although the AS5046 will still produce
usable results at very weak magnetic fields.
if the magnetic field strength is further increased above a magnitude value of 32, LIN will be cleared. The AGC will remain at
255 until the magnitude has reached a value of 63 (yellow range; level B3/B4). The angular data can still be used in the
yellow range, but the noise (=jitter) will be larger than normal.
Once the magnitude is strong enough to reach a value of 63, the AGC will regulate the internal loop gain to maintain this
value. Magnitude will remain at 63 and the AGC will regulate between 0 and 255 (green range; magnetic field strength
between level B3/B4 and B5/B6). This is the recommended operating range
If the magnetic field strength rises further than B5/B4, the AGC can no longer regulate the loop and will be at its minimum
value of 0. The magnitude value will increase (yellow range; up to B7/B8). In this range, the angular data will still be valid.
Due to the rather strong field, there is no issue with noise, but the magnetic field may be more distorted than in the normal
operating range which may lead to additional errors.
Above level B7/B8 the LIN alarm will be set once the magnitude has exceeded a level of 95 (red range). It is not
recommended to operate in this range. The main contributing part for errors will be a more distorted magnetic field.
If the magnitude exceeds a value of 127, the COF (cordic overflow) alarm will be set. This case can only occur with very
strong magnets and does usually not occur in practice. The angular data will be invalid when the COF bit is set.
Figure 9: Magnitude and AGC values vs. magnetic field strength
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AS5046 Programmable 360° Magnetic Angle Encoder – Preliminary Data Sheet
Parameter
Symbol
Min
Typ
Max
Unit
Input Field tolerance level red2yellow B1 - B2
Br2y25
16.77
17.95
19.33
mT
Input Field tolerance level yellow2green B3 - B4
By2g25
33.01
35.35
38.06
mT
Input Field tolerance level green2yellow B5 - B6
Bg2y25
60.0
64.24
69.15
mT
Input Field tolerance level yellow2red B7 – B8
By2r25
90.45
96.87
104.28
mT
Input Field tolerance level red2yellow B1 - B2
Br2y
15.64
17.95
22.37
mT
Input Field tolerance level yellow2green B3 - B4
By2g
30.80
35.35
44.05
mT
Input Field tolerance level green2yellow B5 - B6
Bg2y
55.96
64.24
80.04
mT
Input Field tolerance level yellow2red B7 – B8
By2r
84.39
96.87
120.69
mT
9.7
Note
At 25°C ambient
temperature
Over the full
specified
temperature range
Z-Axis Range Indication (Push Button Feature, Red/Yellow/Green Indicator
The AS5046 provides several options of detecting movement and distance of the magnet in the vertical (Z-) direction. Signal
indicators MagINC, MagDEC and LIN are available as status bits in the serial data stream, while MagRngn is an open-drain
output that indicates an out-of range status (on in YELLOW or RED range). Additionally, the analog output provides a safety
feature in the form that it will be turned off when the magnetic field is too strong or too weak (RED range).
The serial data is always available, the red/yellow/green status is indicated by the status bits as shown below:
Status Bits
Hardware Pins
Description
Mag
INC
Mag
DEC
LIN
Mag
Rngn
Analog
output
0
0
0
Off
0
1
0
Off
1
0
0
Off
1
1
0
On
enabled
YELLOW Range: Magnetic field is ~ 25…45mT or ~75…135mT. The AS5046 may still be operated in this
range, but with slightly reduced accuracy.
1
1
1
On
disabled
RED Range: Magnetic field is ~<25mT or >~135mT. The analog output will be turned off in this range by
default. It can be enabled permanently by OTP programming (see 11.1.2).
It is still possible to use the absolute serial interface in the red range, but not recommended.
enabled
enabled
enabled
No distance change
Magnetic Input Field OK (GREEN range, ~45…75mT)
Distance increase, GREEN range; Pull-function. This state is dynamic and only active while the magnet is
moving away from the chip.
Distance decrease, GREEN range; Push- function. This state is dynamic and only active while the magnet is
moving towards the chip.
Table 7: Magnetic field strength indicators
10 Mode Input Pin
The absolute angular position is sampled at a rate of 10.4kHz (t=96µs) in fast mode and at a rate of 2.6kHz (t=384µs) in
slow mode.
These modes are selected by pin MODE (#2). The mode input pin activates or deactivates an internal filter, which is used to
reduce the digital jitter and consequently the analog output noise.
Activating the filter by pulling Mode = LOW or leaving it open reduces the transition noise to <0.03° rms. At the same time,
the sampling rate is reduced to 2.6kHz and the signal propagation delay is increased to 384µs. This mode is recommended
for high precision, low speed and ≤360° applications.
Deactivating the filter by setting Mode = HIGH increases the sampling rate to 10.4kHz and reduces the signal propagation
delay to 96µs. The transition noise will increase to <0.06° rms. This mode is recommended for higher speed and full scale =
360° applications.
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AS5046 Programmable 360° Magnetic Angle Encoder – Preliminary Data Sheet
Switching the MODE pin affects the following parameters:
Parameter
sampling rate
Slow Mode
(Pin MODE = 0 or
open)
Fast Mode
(Pin MODE = 1)
2.61 kHz
10.42 kHz
(383µs)
(95.9µs)
transition noise
(1 sigma)
≤ 0.03° rms
≤ 0.06° rms
propagation
delay
384µs
96µs
Startup time
20ms
80ms
Table 8: Mode pin settings
Pin MODE should be fixed at power-up. A mode change during operation is not recommended.
Parallel Mode
The Parallel Mode allows connection of up to 8
AS5046’s in parallel on the SCL and SDA line,
maintaining just two wires for data transmission.
This mode is accomplished by connecting all the
SDA and SCL inputs/outputs in parallel. Each
AS5046 device can be programmed one address
ranging from 0…7 (see Table 2)
AS5046
1st Device
Addr. 000
µC
AS5046
2nd Device
Addr. 001
CSn
SDA
SCL
AS5046
8th Device
Addr. 111
CSn
SDA
SCL
CSn
SDA
SCL
SCL
SDA
Figure 10: Parallel connection of up to 8 devices
Note that the parallel connection has some restrictions:
•
Each unit must be programmed to have a different address (ranging from 000 to 111; see Table 2)
•
Changing the address also changes the analog mode, as these OTP bits share the same position.(see Figure 13)
•
Only the SIU containing angle data and status bits can be read from parallel devices (type ID 0101). The other
registers all share the same type identifier (0001, 1011, 0111; see Table 2), which would lead to data collision
when trying to read any of these registers from parallel devices.
11 Ratiometric Analog Angle Output
The analog output V out provides an analog voltage that is proportional to the angle of the rotating magnet and ratiometric to
the supply voltage VDD5V (max.5.5V). It can source or sink currents up to ±1mA in normal operation (up to 66mA short
circuit current).
The analog output block consists of a digital angular range selector, a 10-bit Digital-to-Analog converter and an OPAMP
buffer stage (see Figure 17).
The digital range selector allows a preselection of the angular range for 360°, 180°, 90° or 45° (see Table 9). Fine-tuning of
the angular range can be accomplished by adjusting the gain of the OPAMP buffer stage.
The reference voltage for the Digital-to-Analog converter (DAC) can be taken internally from VDD5V / 2. In this mode, the
output voltage is ratiometric to the supply voltage.
Alternatively, an external DAC reference can be applied at pin DACref (#9). In this mode, the analog output is ratiometric to
the external reference voltage.
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AS5046 Programmable 360° Magnetic Angle Encoder – Preliminary Data Sheet
An on-chip diagnostic feature turns the analog output off in case of an error (broken supply or magnetic field out of range;
see Table 7).The DAC output can be accessed directly at pin #10 DACout.
The addition of an OPAMP to the DAC output allows a variety of user configurable options, such as variable output voltage
ranges and variable output voltage versus angle response. By adding an external transistor, the analog voltage output can
be buffered to allow output currents up to hundred milliamperes or more.
Furthermore, the OPAMP can be configured as constant current source.
As an OTP option, the DAC can be configured to 2 different output ranges:
a) 0……100% V DACref . The reference point may be either taken from VDD5V/2 or from the external DACref input. The
0…100% range allows easy replacement of potentiometers. Due to the nature of rail-to-rail outputs, the linearity will degrade
at output voltages that are close to the supply rails.
b) 10…..90% V DACref . This range allows better linearity, as the OPAMP is not driven to the rails. Furthermore, this mode
allows failure detection, when the analog output voltage is outside of the normal operating range of 10…90%VDD, as in the
case of broken supply or when the magnetic field is out of range and the analog output is turned off.
11.1 Analog Output Voltage Modes
The Analog output voltage modes are programmable by OTP. Depending on the application, the analog output can be
selected as rail-to-rail output or as clamped output with 10%-90% VDD5V.
The output is ratiometric to the supply voltage (VDD5V), which can range from 3.0V to 5.5V. If the DAC reference is
switched to an external reference (pin DACref), the output is ratiometric to the external reference.
11.1.1
Full Scale Mode
This output mode provides a ratiometric DAC output of (0% to 100%)x Vref *) , amplified by the OPAMP stage (default =
internal 2x gain, see Figure 17)
Note: For simplification, Figure 11
describes a linear output voltage from
rail to rail (0V to VDD). In practice, this
is not feasible due to saturation effects
of the OPAMP output driver transistors.
The actual curve will be rounded
towards the supply rails (as indicated in
Figure 11).
Vref
100%
analog
output
voltage
angle
0V
0°
90°
180°
270°
360°
Figure 11: Analog output, full scale mode (shown for 360°mode)
Note: Figure 11 and are shown for 360° operation. See Table 9 (page 24) for further angular range programming options.
11.1.2
Diagnostic Output Mode
In an error case, the output
voltage is in the grey area
Vref
100%
90%
analog
output
voltage
normal
operating
area
10%
0%
0°
90°
180°
270°
360°
angle
In Diagnostic Output Mode (see Figure
12) the analog output of the internal
DAC ranges from 10% - 90% Vref *) . In an
error case, either when the supply is
interrupted or when the magnetic field is
in the “red” range, (see Table 7) the
output is switched to 0V and thus
indicates the error condition.
Figure 12: Diagnostic Output Mode
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AS5046 Programmable 360° Magnetic Angle Encoder – Preliminary Data Sheet
It is possible to enable the analog output permanently (it will not be switched off even if the magnetic field is out of range).
To enable this feature an OTP bit in the factory setting must be set. The corresponding bit is FS6. See application note
AS5040-20 (Extended features of OTP programming) for further details. The application note is available for download at the
austriamicrosystems website.
The analog and digital outputs will have the following conditions:
Status
DAC Output Voltage
normal operation
10% - 90% Vref
magnetic field out of range
< 10% Vref 1) ,
DAC output is switched to
0V
1)
(this feature may be disabled
in OTP; see text)
broken positive power supply
Serial Digital Output
#0 - #1023 (0°-360°),
MagRngn = 1
#0 - #1023 (0°-360°)
out of range is signaled in status
bits:
MagInc=MagDec=LIN=1,
MagRngn= 0
< 10% VDD 2)
(V OUT pull down resistor at receiving side)
broken power supply ground
< 10% VDD 2)
(V OUT pull down resistor at receiving side)
broken positive power supply
> 90% VDD 2)
(V OUT pull up resistor at receiving side)
broken power supply ground
The serial data bits read by the
serial interface will be either all
“0”-s or all “1”-s, indicating a nonvalid output
> 90% VDD 2)
(V OUT pull up resistor at receiving side)
Notes:
1)
Vref = internal: ½ * VDD5V (pin #16) or external: V DACref (pin#9), depending on Ref_extEN bit in OTP (0=int., 1=ext.)
2)
VDD = positive supply voltage at receiving side (3.0 – 5.5V)
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AS5046 Programmable 360° Magnetic Angle Encoder – Preliminary Data Sheet
12 Programming the AS5046
is not required for normal operation. The clock timing t clk
must be selected at a proper rate to ensure that the
signal PROG is stable at the rising edge of CLK (see
Figure 13). Additionally, the programming supply voltage
should be buffered with a 10µF capacitor mounted close
to the switching transistor. This capacitor aids in
providing peak currents during programming. The
specified programming voltage at pin PROG is 7.3 – 7.5V
(see section 5.7). To compensate for the voltage drop
across the V PROG switching transistor, the applied
programming voltage may be set slightly higher (7.5 8.0V, see Figure 15).
After power-on, programming the AS5046 is enabled with
the rising edge of CSn and Prog = logic high. 16 bit
configuration data must be serially shifted into the OTP
register via the Prog-pin. The first “CCW” bit is followed
by the zero position data (MSB first) and the Analog
Output Mode setting as shown in Table 9. Data must be
valid at the rising edge of CLK (see Figure 13). Following
this sequence, the voltage at pin Prog must be raised to
the programming voltage V PROG (see Figure 14). 16 CLK
pulses (t PROG ) must be applied to program the fuses. To
exit the programming mode, the chip must be reset by a
power-on-reset. The programmed data is available after
the next power-up.
OTP Register Contents:
CCW
Counter Clockwise Bit
ccw=0 – angular value increases with clockwise rotation
ccw=1 – angular value increases with counterclockwise rotation
Note: During the programming process, the transitions in
the programming current may cause high voltage spikes
generated by the inductance of the connection cable. To
avoid these spikes and possible damage to the IC, the
connection wires, especially the signals PROG and VSS
must be kept as short as possible. The maximum wire
length between the V PROG switching transistor and pin
PROG (Figure 15) should not exceed 50mm (2 inches).
Z [9:0]: Programmable Zero / Index Position
FB_intEN: OPAMP gain setting: 0=external, 1=internal;
this bit also sets device address bit A2 !
RefExtEN:
To suppress eventual voltage spikes, a 10nF ceramic
capacitor should be connected close to pins PROG and
VSS. This capacitor is only required for programming, it
DAC reference: 0=internal, 1=external;
this bit also sets device address bit A1 !
ClampMd EN:
Analog output span: 0=0-100%,
1=10-90%*VDD;
this bit also sets device address bit A0
Output Range (OR0, OR1):
Analog Output Range Selection
[1:0]
00 = 360°
01 = 180°
10 = 90°
11 = 45°
Disable shutdown of analog output :
see 11.1.2
CSn
tDatain
Prog
CCW
Z9
Z8
Z7
Z6
Z5
1
SCL
tProg enable
tDatain valid
Z4
Z3
Z2
Z1
Z0
FB_int
EN
A2
RefExt
EN
A1
Clamp
Md En
A0
Output
Range1
8
Output
Range0
16
tclk
see text
Zero Position
Analog Modes
Figure 13: Programming Access – OTP Write Cycle (section of Figure 14)
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AS5046 Programmable 360° Magnetic Angle Encoder – Preliminary Data Sheet
Write Data
Programming Mode
Power Off
CSn
Prog
7.5V
VDD
VProgOff
0V
Data
1
16
SCL
tPrgH
tPrgR
tPROG
tLoad PROG
tPROG finished
USB
Figure 14: Complete OTP programming sequence
Figure 15: OTP programming hardware connection of AS5046 (shown with AS5046 demoboard)
12.1 Zero Position Programming
The AS5046 allows easy assembly of the system, as the
actual angle of the magnet does not need to be
considered. By OTP programming, any position can be
assigned as the new permanent zero position with an
accuracy of 0.35° (all modes).
Using the same procedure, the AS5046 can be calibrated
to assign a given output voltage to a given angle. With
this approach, all offset errors (DAC + OPAMP) are also
compensated for the calibrated position.
Revision 1.1
Essentially, for a given mechanical position, the angular
measurement system is electrically rotated (by changing
the Zero Position value in the OTP register), until the
output matches the desired mechanical position.
The example in Figure 16 below shows a configuration
for 5V supply voltage and 10%-90% output voltage
range. It adjusted by Zero Position Programming to
provide an analog output voltage of 2.0 Volts at an angle
of 180°. The slope of the curve may be further adjusted
by changing the gain of the OPAMP output stage and by
selecting the desired angular range (360°/180°/90°/45°).
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AS5046 Programmable 360° Magnetic Angle Encoder – Preliminary Data Sheet
VDD5V
5V
the output can be electrically rotated to
match a given output voltage to any
mechanical position
analog
output
voltage
2V
0V
0°
180°
90°
270°
360°
mechanical
angle
Figure 16: Zero position programming (shown for 360° mode)
12.2 Analog Mode Programming
The analog output can be configured in many ways:
It consists of three major building blocks,
a digital range preselector,
a 10-bit Digital-to-Analog-Converter (DAC)
and an OP-AMP buffer stage.
In the default configuration (all OTP bits = 0), the analog output is set for 360° operation, internal DAC reference
(VDD5V/2), external OPAMP gain, 0-100% ratiometric to VDD5V.
Shown below is a typical example for a 0°-360° range, 0-5V output. The complete application requires only one external
component, a buffer capacitor at VDD3V3 and has only 3 connections VDD, VSS and Vout (connectors 1-3).
Note: the default setting for the OPAMP feedback path is:FB_intEn=0=external. The external resistors Rf and Rg must be
installed. In the programmed state (FB_intEn=1=internal), these resistors do not need to be installed as the feedback path is
internal (Rf_int and Rg_int).
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AS5046 Programmable 360° Magnetic Angle Encoder – Preliminary Data Sheet
1
Mode pin.
Default = open
(low noise)
External DAC reference pin.
Leave open or connect to
VSS if not used
9
2
DACref
Mode
MagRngn
Connect pins 15 and 16
for VDD = 3.0 – 3.6V.
Do NOT connect for
VDD = 4.5 – 5.5V!
16
VDD5V
LDO
3.3V
REF_ extEN
15
VDD3V3
+
Magnetic field range alarm. Active
low. Leave open or connect to
VSS if not used
1= ext
0
0
1
1
OR1
from
DSP
360 °
180 °
90 °
45 °
1-10µF
VDD5V / 2
0
1
0
1
0= int
10
Vref
OR0
Range
Selector
10 bit
digital
DAC
DACout
0 - 100 % VDD5 V /2
10bit
analog
+
VOUT
-
ClampMdEN
0=ext
0 = 0-100 % * Vref ( def.)
1 = 10-9 0 % * Vref
FB_intEN
Rf_int
30k
3
4
6
Digital serial
interface, 10bit/360°.
Leave open if not
used. CSn and CLK
may also be tied to
VSS if no used
8
for OTP
programming and
alignment mode
only. Leave open
or connect to VSS
if not used
NC
5
NC
13
RLmin
= 4k7
CL
<100pF
Rg
11
OP-Amp feedback pin.
Leave open if not used.
VSS
7
14
Test pins.
Leave open
Rf
Rg_int
30k
FB
NC
12
1=int
Gain = 2 x (int)
CSn SCL SDO PROG
DAC output pin.
Leave open if no used
VDD
Vout
0
360 °angle
Figure 17: Analog output block diagram
12.2.1
Angular Range Selector
The Angular Range selector allows a digital pre-selection
of the angular range. The AS5046 can be configured for
a full scale angular range of 45°, 90°, 180° or 360°. In
addition, the Output voltage versus angle response can
be fine-tuned by setting the gain of the OP-AMP with
external resistors and the maximum output voltage can
be set in the DAC.
The combination of these options allows to configure the
operation range of the AS5046 for all angles up to 360°
and output voltages up to 5.5V
Revision 1.1
The response curve for the analog output is linear for the
selected range (45°/90°/180°/360°). In addition, the
slope is mirrored at 180° for 45°- and 90°- modes and
has a step response at 270° for the 180°-mode. This
allows the AS5046 to be used in a variety of applications.
In these three modes, the output remains at V out,max and
V out,min to avoid a sudden output change when the
mechanical angle is rotated beyond the selected analog
range. In 360°-mode, a jitter between V out,max and V out,min
at the 360° point is also prevented due to a hysteresis.
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AS5046 Programmable 360° Magnetic Angle Encoder – Preliminary Data Sheet
Output
Output
Range1
Range0
Mode
Note
3 60 ° a n g ula r ran g e (de fa u lt)
1 0 23
0
0
default mode,
a na lo g
ou tp u t
0
analog resolution= 10bit
(1024 steps) over 360°
0
0°
1024
90°
2 0 48
180°
3 0 72
270°
4 09 6 = 0
360°
a ng le 1 )
analog step size:
1LSB = 0.35° (10bit)
1 80 ° a n g ula r ran g e
1 0 23
0
1
analog resolution= 10bit
(1024 steps) over 180°
a n a log
o u tp u t
Analog step size:
0
0
0°
1 0 24
90°
2 04 8
180°
3 0 72
270°
4 09 6 = 0
360°
a n g le
1LSB = 0.175° (11bit)
9 0° a n g u la r ra ng e
1 0 23
1
0
analog resolution= 10bit
(1024 steps) over 90°
a n a log
o u tp u t
0
0
0°
1 0 24
90°
2 04 8
180°
3 0 72
270°
4 09 6 = 0
360°
Analog step size:
1LSB = 0.088° (12bit)
a n g le
4 5° a n g u la r ra ng e
511
analog resolution=
1
1
a n a log
o u tp u t
0
9 bit (512 steps) over 45°
0 5 12 1 0 24
0° 45° 90°
2 04 8
180°
25 6 0
225°
4 09 6 = 0
360°
a n g le
Analog step size:
1LSB = 0.088° (12bit)
Note: 1) The resolution on the digital serial interface is always 12bit (0.088°/step) over 360°, independent of analog mode
Table 9: Digital Range Selector programming option
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AS5046 Programmable 360° Magnetic Angle Encoder – Preliminary Data Sheet
12.3 Repeated OTP Programming
Although a single AS5046 OTP register bit can be
programmed only once (from 0 to 1), it is possible to
program other, unprogrammed bits in subsequent
programming cycles. However, a bit that has already
been programmed should not be programmed twice.
Therefore it is recommended that bits that are already
programmed are set to “0” during a programming cycle.
12.4 Non-permanent Programming
It is also possible to re-configure the AS5046 in a nonpermanent way by overwriting the OTP register.
This procedure is essentially a “Write Data” sequence
(see Figure 13) without a subsequent OTP programming
cycle.
The “Write Data” sequence may be applied at any time
during normal operation. This configuration remains set
while the power supply voltage is above the power-on
reset level (see 5.5).
See Application Note AN5000-20 for further information.
12.5 Digital-to-Analog Converter (DAC)
The DAC has a resolution of 10bit (1024 steps) and can
be configured for the following options
Internal or external reference
The default DAC reference is the voltage at pin #16
(VDD5V) divided by 2 (see Figure 17). Using this
reference, a system that has an output voltage
ratiometric to the supply voltage can be built.
Optionally, an external reference source, applied at pin#9
(DACref) can be used. This programming option is useful
for applications requiring a precise output voltage that is
independent of supply fluctuations, for current sink
outputs or for applications with a dynamic reference, e.g.
attenuation of audio signals.
The default full scale output voltage range is 0100%*VDD5V. Due to limitations in the output stage of
an OP-Amp buffer, it cannot drive the output voltage from
0-100% rail-to-rail. Without load, the minimum output
voltage at 0° will be a few millivolts higher than 0V and
the maximum output voltage will be slightly lower than
VDD5V. With increasing load, the voltage drops will
increase accordingly.
As a programming option, an output range of 1090%*VDD5V can be selected. In this mode, there is no
saturation at the upper and lower output voltage limits
like in the 0-100% mode and it allows failure detection as
the output voltage will be outside the 10-90% limits,
when the magnetic field is in the “red” range (V out =0V,
see Table 7) or when the supply to the chip is interrupted
(V out =0V or VDD5V).
The unbuffered output of the DAC is accessible at pin
#10 (DACout). This output must not be loaded.
12.6 OP-AMP Stage
The DAC output is buffered by a non-inverting Op-Amp
stage. The amplifier is supplied by VDD5V (pin #16) and
can hence provide output voltages up to 5V.
By allowing access to the inverting input of the Op-Amp
and with the addition of a few discrete components it can
be configured in many ways, like high current buffer,
current sink output, adjustable angle range, etc...
Per default, the gain of the Op-Amp must be set by two
external resistors (see Figure 17). Optionally, the fixed
internal gain setting (2x) may be programmed by OTP,
eliminating the need for external resistors.
12.6.1
Output Noise
The Noise level at the analog output depends on two
states of the digital angular output:
a)
the digital angular output value is stable
In this case, the output noise is the figure given
as V noise in paragraph 0. Note that the noise
level is given for the default gain of 2x For
other gains, it must be scaled accordingly.
b)
the digital output is at the edge of a step
In this case, the digital output may jitter
between two adjacent values. The rate of jitter
is specified as transition noise (parameter TN
in paragraph 5.5). The resulting output noise is
calculated by:
0-100% or 10-90% full scale range
The reference voltage for the DAC is buffered internally.
The recommended range for the external reference
voltage is 0.2V to (VDD3V3 -0.2)V.
The DAC output voltage will be switched to 0V, when the
magnetic field is out of range, when the MagInc and
MagDec indicators are both =1 and the MagRngn-pin (#1)
will go low.
Vnoise ,Vout =
Revision 1.1
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TN ∗ VDD5V
+ Vnoise ,OPAMP
360
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AS5046 Programmable 360° Magnetic Angle Encoder – Preliminary Data Sheet
where:
V noise, Vout
= noise level at pin Vout in Vrms
TN
= transition noise (in °rms; see 5.5)
VDD5V
= Supply voltage VDD5V in V
V noise,OPAMP
= noise level of OPAMP
(paragraph 0) in Vrms
12.7 Application Examples
Application Note AN5043-10 shows various application
examples for the AS5043 encoder IC. The same
application examples apply for the analog output of the
AS5046.
13 Analog Readback Mode
Non-volatile programming (OTP) uses on-chip zener diodes, which become permanently low resistive when subjected to a
specified reverse current.
The quality of the programming process depends on the amount of current that is applied during the programming process
(up to 130mA). This current must be provided by an external voltage source. If this voltage source cannot provide adequate
power, the zener diodes may not be programmed properly.
In order to verify the quality of the programmed bits, an analog level can be read for each zener diode, giving an indication
whether this particular bit was properly programmed or not.
To put the AS5046 in Analog Readback Mode, a digital sequence must be applied to pins CSn, PROG and CLK as shown in
Figure 18. The digital level for this pin depends on the supply configuration (3.3V or 5V; see section 7, page 9).
The second rising edge on CSn (OutpEN) changes pin PROG to a digital output and the log. high signal at pin PROG must
be removed to avoid collision of outputs (grey area in Figure 18).
The following falling slope of CSn changes pin PROG to an analog output, providing a reference voltage V ref , that must be
saved as a reference for the calculation of the subsequent programmed and unprogrammed OTP bits.
Following this step, each rising slope of CLK outputs one bit of data in the reverse order as during programming.
(see Figure 18: Output Range OR0 and -1 , ClampMdEn, RefExtEn, FB_IntEn, Z0…Z9, ccw)
During analog readback, the capacitor at pin PROG (see Figure 15) should be removed to allow a fast readout rate.
The measured analog voltage for each bit must be subtracted from the previously measured V ref , and the resulting value
gives an indication on the quality of the programmed bit: a reading of <100mV indicates a properly programmed bit and a
reading of >1V indicates a properly unprogrammed bit.
A reading between 100mV and 1V indicates a faulty bit, which may result in an undefined digital value, when the OTP is
read at power-up.
Following the 16 th clock (after reading bit “ccw”), the chip must be reset by disconnecting the power supply.
Figure 18: Analog OTP Register Read
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AS5046 Programmable 360° Magnetic Angle Encoder – Preliminary Data Sheet
14 Alignment Mode
15 Choosing the Proper Magnet
The alignment mode simplifies centering the magnet over
the chip to gain maximum accuracy and XY-alignment
tolerance.
Typically the magnet should be 6mm in diameter and ≥2.5mm in
height. Magnetic materials such as rare earth AlNiCo, SmCo5 or
NdFeB are recommended.
This electrical centering method allows a wider XYalignment tolerance (0.485mm radius) than mechanical
centering (0.25mm radius) as it eliminates the placement
tolerance of the die within the IC package (+/- 0.235mm).
Alignment mode can be enabled with the falling edge of
CSn while PROG = logic high (Figure 19). The Data bits
D11-D0 of the serial interface 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.
The magnet’s field strength perpendicular to the die
surface should be verified using a gauss-meter. The
magnetic field B v at a given distance, along a concentric
circle with a radius of 1.1mm (R1), should be in the range
of ±45mT…±75mT. (see Figure 21).
typ. 6mm diameter
N
S
Under normal conditions, a properly aligned magnet will
result in a reading of less than 128 over a full turn.
Stronger magnets or short gaps between magnet and IC
may show values larger than 128. These magnets are
still properly aligned as long as the difference between
highest and lowest value over one full turn is at a
minimum.
Magnet axis
R1
Magnet axis
Vertical field
component
The MagInc and MagDec indicators will be = 1 when the
alignment mode reading is < 128. At the same time,
hardware pin MagRngn (#1) will be pulled to VSS.
The Alignment mode can be reset to normal operation
mode by a power-on-reset (cycle power supply) or by a
falling edge of CSn with PROG=low (see Figure 20).
R1 concentric circle;
radius 1.1mm
Vertical field
component
Bv
(45…75mT)
0
360
360
Figure 21: Typical magnet and magnetic field distribution
Figure 19: Enabling the alignment mode
Figure 20: Exiting alignment mode
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AS5046 Programmable 360° Magnetic Angle Encoder – Preliminary Data Sheet
15.1 Physical Placement of the Magnet
The best linearity can be achieved by placing the center
of the magnet exactly over the defined center of the IC
package as shown in Figure 22:
3.9 mm
16 Simulation Modeling
3.9 mm ±0.235mm
1
3.9 mm
1
2.433
mm
Y1
±0.235mm
X1
2.433 mm
X2
Defined
center
Y2
Rd
2.433 mm
Area of recommended maximum
magnet misalignment
AS5046 die
Center of die
Radius of circular Hall sensor
array: 1.1mm radius
Figure 22: Defined IC center and magnet displacement radius
Figure 24: Arrangement of Hall sensor array on chip (principle)
15.1.1
Magnet Placement
The magnet’s center axis should be aligned within a
displacement radius R d of 0.25mm from the defined
center of the IC with reference to the edge of pin #1 (see
Figure 22). This radius includes the placement tolerance
of the chip within the SSOP-16 package (+/- 0.235mm).
The displacement radius R d is 0.485mm with reference to
the center of the chip (see section 14: Alignment Mode).
The vertical distance should be chosen such that the
magnetic field on the die surface is within the specified
limits (see Figure 21). The typical distance “z” between
the magnet and the package surface is 0.5mm to 1.8mm
with the recommended magnet (6mm x 3mm). Larger
gaps are possible, as long as the required magnetic field
strength stays within the defined limits.
A magnetic field outside the specified range may still
produce usable results, but the out-of-range condition
will be indicated by MagRngn (pin 1), which will be pulled
low. At this condition, the angular data is still available
over the digital serial interface, but the analog output will
be turned off.
N
Die surface
z
0.576mm ± 0.1mm
1.282mm ± 0.15mm
Figure 23: Vertical placement of the magnet
Revision 1.1
The differential signal Y1-Y2 will give a sine vector of
the magnetic field. The differential signal X1-X2 will give
an orthogonally related cosine vector of the magnetic
field.
The angular displacement (Θ) of the magnetic source
with reference to the Hall sensor array may then be
modelled by:
Θ = arctan
(Y 1 − Y 2) ± 0.5°
( X 1 − X 2)
The ±0.5° angular error assumes a magnet optimally
aligned over the center of the die and is a result of gain
mismatch errors of the AS5046. Placement tolerances of
the die within the package are ±0.235mm in X and Y
direction, using a reference point of the edge of pin #1
(Figure 24)
S
Package surface
With reference to Figure 24, a diametrically magnetized
permanent magnet is placed above or below the surface
of the AS5046. The chip uses an array of Hall sensors to
sample the vertical vector of a magnetic field distributed
across the device package surface. The area of magnetic
sensitivity is a circular locus of 1.1mm radius with
respect to the center of the die. The Hall sensors in the
area of magnetic sensitivity are grouped and configured
such that orthogonally related components of the
magnetic fields are sampled differentially.
In order to neglect the influence of external disturbing
magnetic fields, a robust differential sampling and
ratiometric calculation algorithm has been implemented.
The differential sampling of the sine and cosine vectors
removes any common mode error due to DC components
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AS5046 Programmable 360° Magnetic Angle Encoder – Preliminary Data Sheet
introduced by the magnetic source itself or external
disturbing magnetic fields. A ratiometric division of the
sine and cosine vectors removes the need for an
accurate absolute magnitude of the magnetic field and
thus accurate Z-axis alignment of the magnetic source.
18 Angular Output Tolerances
18.1 Accuracy; Digital Outputs
Accuracy is defined as the error between measured
angle and actual angle. It is influenced by several
factors:
The recommended differential input range of the
magnetic field strength (B (X1-X2) ,B (Y1-Y2) ) is ±75mT at the
surface of the die. In addition to this range, an additional
offset of ±5mT, caused by unwanted external stray fields
is allowed.
The chip will continue to operate, but with degraded
output linearity, if the signal field strength is outside the
recommended range. Too strong magnetic fields will
introduce errors due to saturation effects in the internal
preamplifiers. Too weak magnetic fields will introduce
errors due to noise becoming more dominant.
17 Failure Diagnostics
The AS5046 also offers several diagnostic and failure
detection features:
ƒ
the non-linearity of the analog-digital converters,
ƒ
internal gain and mismatch errors,
ƒ
non-linearity due to misalignment of the magnet
As a sum of all these errors, the accuracy with centered
magnet = (Err max – Err min )/2 is specified as better than
±0.5 degrees @ 25°C (see Figure 26).
Misalignment of the magnet further reduces the
accuracy. Figure 25 shows an example of a 3D-graph
displaying non-linearity over XY-misalignment. The
center of the square XY-area corresponds to a centered
magnet (see dot in the center of the graph). The X- and
Y- axis extends to a misalignment of ±1mm in both
directions. The total misalignment area of the graph
covers a square of 2x2 mm (79x79mil) with a step size of
100µm.
17.1 Magnetic Field Strength Diagnosis
For each misalignment step, the measurement as shown
in Figure 26 is repeated and the accuracy
By software: the MagInc and MagDec status bits will
both be high when the magnetic field is out of range.
(Err max – Err min )/2 (e.g. 0.25° in Figure 26) is entered as
the Z-axis in the 3D-graph.
By hardware: Pin #1 (MagRngn) is a logical NAND-ed
combination of the MagInc and MagDec status bits. It is
an open-drain output and will be turned on (= low with
external pull-up resistor) when the magnetic field is out
of range.
18.2 Accuracy; Analog Output
By hardware: Pin #12 (Vout) is the analog output of the
DAC and OP-Amp. The analog output will be 0V, when
the magnetic field is out of range (all analog modes).
The analog output has the same accuracy as the digital
output with the addition of the nonlinearities of the DAC
and the OPAMP (+/-1LSB; see Table 9 and 0).
Linearity Error over XY-misalignment [°]
17.2 Power Supply Failure Detection
By software: If the power supply to the AS5046 is
interrupted, the digital data read by the serial interface
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
6
5
4
°
resistor (~10kΩ) should be added between pin DO and
VSS at the receiving side
800
500
2
200
1
-100
x
-800
-1000
-1000
-400
0
-600
y
-700
-200
200
600
-400
400
1000
0
800
By hardware: The MagRngn pin is an open drain output
and requires an external pull-up resistor. In normal
operation, this pin is high ohmic and the output is high.
In a failure case, either when the magnetic field is out of
range or the power supply is missing, this output will
become low. To ensure an adequate low level in case of
a broken power supply to the AS5046, the pull-up
3
Figure 25: Example of linearity error over XY misalignment
resistor (~10kΩ) must be connected to the positive
supply at pin 16 (VDD5V).
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AS5046 Programmable 360° Magnetic Angle Encoder – Preliminary Data Sheet
The maximum non-linearity error on this example is
The total nonlinearity error over process tolerances,
temperature and a misalignment circle radius of 0.25mm
better than ±1 degree (inner circle) over a misalignment
radius of ~0.7mm. For volume production, the placement
is specified better than ±1.4 degrees.
tolerance of the IC within the package (±0.235mm) must
also be taken into account.
linearity
error
with
The magnet used for this measurement was a cylindrical
NdFeB (Bomatec® BMN-35H) magnet with 6mm diameter and
2.5mm in height.
centered
magnet
0.5
0.4
0.3
0.2
transition noise
0.1
0
-0.1
Err max
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
Figure 26: Example of linearity error over 360°
18.3 Transition Noise
In 180°, 90° or 45° mode, where the step sizes
are smaller, slow mode should be selected to
reduce the output jitter.
Transition noise is defined as the jitter in the transition
between two steps.
Due to the nature of the measurement principle (Hall
sensors + Preamplifier + ADC), there is always a certain
degree of noise involved.
This transition noise voltage results in an angular
transition noise at the outputs. It is specified as 0.06
degrees rms (1 sigma) *1 in fast mode (pin MODE = high)
and 0.03 degrees rms (1 sigma) *1 in slow mode (pin
MODE = low or open).
These values are 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:
ƒ
ƒ
absolute output; serial interface:
The transition noise of the absolute output can
be reduced by the user by applying an
averaging of readings. An averaging of 4
readings will reduce the transition noise by 6dB
or 50%, e.g. from 0.03°rms to 0.015°rms (1
sigma) in slow mode
analog output:
Ideally, the analog output should have a jitter
that is less than one digit. In 360° mode, both
fast or slow mode may be selected for adequate
low jitter.
Revision 1.1
: statistically, 1 sigma represents 68.27% of readings,
3 sigma represents 99.73% of readings.
*1
18.4 High Speed Operation
18.4.1
Sampling Rate
The AS5046 samples the angular value at a rate of
10.42k samples per second (ksps) in fast mode and
2.61ksps in slow mode.
Consequently, a new reading is performed each 96µs.
(fast mode) or 384µs (slow mode).
At a stationary position of the magnet, this sampling rate
creates no additional error.
Absolute Mode:
With the given sampling rates, the number of samples (n)
per turn for a magnet rotating at high speed can be
calculated by
n=
60
for fast mode
rpm ⋅ 96 μs
n=
60
for slow mode
rpm ⋅ 384 μs
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AS5046 Programmable 360° Magnetic Angle Encoder – Preliminary Data Sheet
In practice, there is no upper speed limit. The only restriction is
that there will be fewer samples per revolution as the speed
increases.
Regardless of the rotational speed, the absolute angular value is
always sampled at the highest resolution.
18.6 Internal Timing Tolerance
The AS5046 does not require an external ceramic
resonator or quartz. All internal clock timings for the
AS5046 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:
Fast Mode
(pin Mode = 1)
Slow Mode
610rpm = 1024 samples / turn
610rpm = 256 samples / turn
18.6.1
1220rpm = 512 samples / turn
1220rpm = 128 samples / turn
A new angular value is updated every
2441rpm = 256 samples / turn
2441rpm = 64 samples / turn
96µs +/- 5% (Mode = 1) or
etc…
etc…
(pin Mode = 0 or open)
Absolute Output; Serial Interface
384µs +/- 5% (Mode = 0 or open)
Table 10: Speed performance
18.5 Output Delays
18.7 Temperature
The propagation delay is the delay between the time that
the sample is taken until it is available as angular data.
This delay is 96µs in fast mode (pin Mode = high) and
384µs in slow mode (pin Mode = low or open)
The analog output produces no further delay, the output
voltage will be updated as soon as it is available. Using
the serial interface for data transmission, an additional
delay must be considered, caused by the asynchronous
sampling (0….1/f sample ) and the time it takes the external
control unit to read and process the angular data from
the AS5046.
18.5.1
Angular Error Caused by Propagation
Delay
A rotating magnet will cause an angular error caused by
the propagation delay.
18.7.1
Magnetic Temperature Coefficient
One of the major benefits of the AS5046 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 AS5046 automatically compensates for the varying
magnetic field strength over temperature. The magnet’s
temperature drift does not need to be considered, as the
AS5046 operates with magnetic field strengths from
±45…±75mT.
Example:
A NdFeB magnet has a field strength of 75mT @ –40°C and a
temperature coefficient of -0.12% per Kelvin. The temperature
change is from –40° to +125° = 165K.
This error increases linearly with speed:
The magnetic field change is: 165 x -0.12% = -19.8%, which
corresponds to 75mT at –40°C and 60mT at 125°C .
e sampling (deg) = 6 ∗ rpm ∗ pr.delay
The AS5046 can compensate for this temperature related
field strength change automatically, no user adjustment
is required.
where
e sampling = angular error [°]
rpm = rotating speed [rpm]
prop.delay = propagation delay [seconds]
Note: since the propagation delay is known, it can be
automatically compensated by the control unit processing
the data from the AS5046.
18.7.2
Accuracy over Temperature
The influence of temperature in the absolute accuracy is
very low. While the accuracy is ≤ ±0.5° at room
temperature, it may increase to ≤±0.9° due to increasing
noise at high temperatures.
18.7.3
Timing Tolerance over Temperature
The internal RC oscillator is factory trimmed to ±5%.
Over temperature, this tolerance may increase to ±10%.
Generally, the timing tolerance has no influence in the
accuracy or resolution of the system, as it is used mainly
for internal clock generation.
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AS5046 Programmable 360° Magnetic Angle Encoder
19 Package Drawings and Markings
16-Lead Shrink Small Outline Package SSOP-16
AYWWIZZ
AS5046
Marking: AYWWIZZ
A: Pb-Free Identifier
Dimensions
mm
Symbol
Y: Last Digit of Manufacturing Year
inch
WW: Manufacturing Week
Min
Typ
Max
Min
Typ
Max
A
1.73
1.86
1.99
.068
.073
.078
I: Plant Identifier
A1
0.05
0.13
0.21
.002
.005
.008
ZZ: Traceability Code
A2
1.68
1.73
1.78
.066
.068
.070
b
0.25
0.315
0.38
.010
.012
.015
c
0.09
-
0.20
.004
-
.008
D
6.07
6.20
6.33
.239
.244
.249
E
7.65
7.8
7.9
.301
.307
.311
E1
5.2
5.3
5.38
.205
.209
.212
e
0.65
K
0°
-
8°
0°
-
8°
L
0.63
0.75
0.95
.025
.030
.037
.0256
JEDEC Package Outline Standard:
MO - 150 AC
Thermal Resistance R th(j-a) :
typ. 151 K/W in still air, soldered on PCB
IC’s marked with a white dot or the
letters “ES” denote Engineering samples
20 Packing Options
Delivery:
Tape and Reel (1 reel = 2000 devices)
Tubes (1 box = 100 tubes á 77 devices)
Order # AS5046ASSU
for delivery in tubes
Order # AS5046ASST
for delivery in tape and reel
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AS5046 Programmable 360° Magnetic Angle Encoder
21 Recommended PCB Footprint
Recommended Footprint Data
A
B
C
D
E
mm
9.02
6.16
0.46
0.65
5.01
inch
0.355
0.242
0.018
0.025
0.197
22 Contact
22.1 Headquarters
austriamicrosystems AG
A 8141 Schloss Premstätten, Austria
Phone:
+43 3136 500 0
Fax:
+43 3136 525 01
www.austriamicrosystems.com
Copyrights
Copyright © 1997-2007, austriamicrosystems AG, Schloss Premstaetten, 8141 Unterpremstaetten, 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.
All products and companies mentioned are trademarks or registered trademarks of their respective companies.
This product is protected by U.S. Patent No. 7,095,228.
Disclaimer
Devices sold by austriamicrosystems AG are covered by the warranty and patent indemnification provisions appearing in its
Term of Sale. austriamicrosystems AG makes no warranty, express, statutory, implied, or by description regarding the
information set forth herein or regarding the freedom of the described devices from patent infringement. austriamicrosystems
AG reserves the right to change specifications and prices at any time and without notice. Therefore, prior to designing this
product into a system, it is necessary to check with austriamicrosystems AG for current information. This product is intended for
use in normal commercial applications. Applications requiring extended temperature range, unusual environmental
requirements, or high reliability applications, such as military, medical life-support or lifesustaining equipment are specifically
not recommended without additional processing by austriamicrosystems AG for each application.
The information furnished here by austriamicrosystems AG is believed to be correct and accurate. However,
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