ams AS5055 Low power 12-bit magnetic rotary encoder Datasheet

AS5055
Low Power 12-Bit Magnetic Rotary Encoder
1 General Description
2 Key Features
12-bit resolution
The AS5055 is a single-chip magnetic rotary encoder IC with low
voltage and low power features.
Standard SPI interface, 3 or 4 wire
It includes 4 integrated Hall elements, a high resolution ADC and a
smart power management controller.
3.0V to 3.6V core voltage, 1.8V to 3.6V peripheral supply
voltage
The angle position, alarm bits and magnetic field information are
transmitted over a standard 3-wire or 4-wire SPI interface to the host
processor.
Automatic wake-up over SPI interface
Interrupt output for conversion complete indication
Low power mode:
The AS5055 is available in a small QFN 16-pin 4x4x0.85 mm
package and specified over an operating temperature of -40ºC to
+85ºC.
- < 5mA (avg) @ 1ms readout interval
- < 500µA (avg) @ 10ms readout interval
- < 53µA (avg) @ 100ms readout interval
Small size 16-pin QFN (4x4x0.85 mm)
3 Applications
The device is ideal for Servo motor control, Input device for battery
operated portable devices, and Robotics.
Figure 1. AS5055 Block Diagram
AS5055
EN_INT/
ADC
INT/
Cordic
Hall Sensors
SPI Interface
Power Management
VDD
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VSS
Wire
mode
MOSI
Revision 1.16
MISO
VDDp
SCK
SS/
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AS5055
Datasheet - C o n t e n t s
Contents
1 General Description ..................................................................................................................................................................
1
2 Key Features.............................................................................................................................................................................
1
3 Applications...............................................................................................................................................................................
1
4 Pin Assignments .......................................................................................................................................................................
3
4.1 Pin Descriptions....................................................................................................................................................................................
3
5 Absolute Maximum Ratings ......................................................................................................................................................
4
6 Electrical Characteristics...........................................................................................................................................................
5
6.1 Operating Conditions............................................................................................................................................................................
5
6.2 System Parameters ..............................................................................................................................................................................
5
6.3 DC/AC Characteristics..........................................................................................................................................................................
6
7 Detailed Description..................................................................................................................................................................
7
7.1 Operating Modes ..................................................................................................................................................................................
7.1.1
7.1.2
7.1.3
7.1.4
7.2 SPI Communication..............................................................................................................................................................................
7.2.1
7.2.2
7.2.3
7.2.4
7.2.5
7.2.6
7
8
8
8
9
Command Package ..................................................................................................................................................................... 9
Read Package (Value Read from AS5055) ................................................................................................................................. 9
Write Data Package (Value Written to AS5055) ........................................................................................................................ 10
Register Block............................................................................................................................................................................ 10
SPI Interface Commands........................................................................................................................................................... 11
Error Monitoring .......................................................................................................................................................................... 14
8 Application Information ...........................................................................................................................................................
16
8.1 SPI Interface.......................................................................................................................................................................................
8.1.1
8.1.2
8.1.3
8.1.4
7
Power Supply Filter......................................................................................................................................................................
Reading an Angle ........................................................................................................................................................................
Low Power Mode .........................................................................................................................................................................
Interrupt Chaining ........................................................................................................................................................................
SPI Interface Signals (4-Wire Mode, Wire_mode = 1)...............................................................................................................
SPI Timing .................................................................................................................................................................................
SPI Connection to the Host µC .................................................................................................................................................
SPI Over Long Distances ..........................................................................................................................................................
8.2 Placement of the Magnet....................................................................................................................................................................
16
16
17
18
20
21
9 Package Drawings and Markings ...........................................................................................................................................
22
10 Ordering Information.............................................................................................................................................................
25
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AS5055
Datasheet - P i n A s s i g n m e n t s
4 Pin Assignments
NC
INT/
Wire_mode
VSS
Figure 2. Pin Assignments (Top View)
16
15
14
13
MOSI
1
12
VDD
MISO
2
11
VDDp
SCK
3
10
En_INT/
SS/
4
9
Test_coil
5
6
7
8
NC
NC
NC
NC
Epad
4.1 Pin Descriptions
Table 1. Pin Descriptions
Pin Number
Pin Name
Pin Type
1
MOSI
Digital input
2
MISO
Digital output, tri-state buffer SPI bus data output
3
SCK
Digital input Schmitt trigger SPI Clock Schmitt trigger
4
SS/
5
NC
6
NC
7
NC
8
NC
9
Test coil
Supply
Test pin, connect to VSS
10
En_INT/
Digital input
Enable / disable Interrupt
11
VDDp
12
VDD
13
VSS
14
Wire_mode
15
INT/
16
NC
-
Leave unconnected
Epad
-
-
Center pad not connected
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Digital input
-
Description
SPI bus data input
SPI Slave Select, active LOW
Leave unconnected
Peripheral power supply, 1.8V ~ VDD
Supply
Analog and digital power supply, 3.0 ~ 3.6V
Supply ground
Digital I/O
0: 3-wire mode
1: 4-wire mode
Digital output, tri-state buffer Interrupt output. Active LOW, when conversion is finished
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AS5055
Datasheet - A b s o l u t e M a x i m u m R a t i n g s
5 Absolute Maximum Ratings
Stresses beyond those listed in Table 2 may cause permanent damage to the device. These are stress ratings only, and functional operation of
the device at these or any other conditions beyond those indicated in Electrical Characteristics on page 5 is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect device reliability.
Table 2. Absolute Maximum Ratings
Symbol
Parameter
Min
Max
Units
Comments
VDD
DC supply voltage
-0.3
5.0
V
Value of these process dependent parameters
to be taken from according Process Parameter
document, current version
VDDp
Peripheral supply voltage
-0.3
VDD+0.3
V
VIN
Input pin voltage
-0.3
5.0
V
Iscr
Input current (latchup immunity)
-100
100
mA
Norm: Jedec 78
Electrical Parameters
Electrostatic Discharge
ESD
Electrostatic discharge
±1
-
kV
Norm: MIL 883 E method 3015
ΘJA
Package thermal resistance
-
33.5
°C/W
Velocity=0, Multi Layer PCB;
Jedec Standard Testboard
36
mW
125
°C
Continuous Power Dissipation
Pt
Total power dissipation
Temperature Ranges and Storage Conditions
Tstrg
TBODY
Storage temperature
-55
Package body temperature
Humidity non-condensing
MSL
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Moisture Sensitive Level
5
260
°C
85
%
3
Revision 1.16
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).
Represents a maximum floor life time of 168h
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AS5055
Datasheet - E l e c t r i c a l C h a r a c t e r i s t i c s
6 Electrical Characteristics
6.1 Operating Conditions
Table 3. Operating Conditions
Parameter
Conditions
Min
Max
Units
VDD
3.0
3.6
V
Peripheral supply voltage
VDDp
1.8
VDD
V
Input pin voltage
VIN
-0.3
VDDp +0.3
V
-40
85
°C
Power supply filter, pin VDD
(refer to Power Supply Filter on page 7)
2.2
4.7
µF
15
33
Ω
Ceramic capacitor, pin VDDp to VSS
100
DC supply voltage
1
Ambient operating temperature
External component
Typ
nF
1. VDDp must not exceed VDD (protection diode between VDDp and VDD)
6.2 System Parameters
Table 4. System Parameters
Symbol
Parameter
Conditions
I_10
Operating current
Average current @ 10 ms readout rate
I_100
I_max
Min
Max
Units
1
0.4
mA
Operating current
Average current @ 100 ms readout rate
40
µA
Operating current
Maximum readout rate
8.5
mA
Readout rate
Time between READ ANGLE command and
INTERRUPT
430
µs
Power down current
Power down current
3
µA
Rd
Lateral displacement range
Centre of the magnet to the centre of the die
± 0.5
mm
BZ
Magnetic field strength
80
mT
320
30
Serial interface
Typ
-
SPI mode 1 (CPOL = 0 / CPHA =1)
Resolution; magnetic field
measurement
12
bit
Resolution; angle
12
bit
INL
Best-fit line - over supply, displacement and
temperature – but without quantization
IC package
-1.41
1.41
degree
QFN 4x4x0.85
1. Without the time for the SPI interface
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AS5055
Datasheet - E l e c t r i c a l C h a r a c t e r i s t i c s
6.3 DC/AC Characteristics
Digital pads: MISO, MOSI, SCK, SS/, EN_INT/, INT/, Wire_mode
Table 5. DC/AC Characteristics
Symbol
Parameter
VIH
High level input voltage
VIL
Low level input voltage
VDDp > 2.7V
0.3 * VDDp
V
VIL
Low level input voltage
VDDp < 2.7V
0.25 * VDDp
V
ILEAK
Input leakage current
1
µA
VOH
High level output voltage
VOL
Low level output voltage
VSS + 0.4
V
CL
Capacitive load
35
pF
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Conditions
Min
Typ
Max
0.7 * VDDp
V
VDDp - 0.5
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Units
V
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AS5055
Datasheet - D e t a i l e d D e s c r i p t i o n
7 Detailed Description
User Programming.
The AS5055 does not require any programming by the user. A dedicated on-chip zero position programming is not implemented. If a zero
position programming is required, it is recommended to store the zero position offset in the host controller.
7.1 Operating Modes
Typical Application.
The AS5055 requires only a few external components in order to operate immediately when connected to the host microcontroller. Only 6 wires
are needed for a simple application using a single power supply: two wires for power and four wires for the SPI communication. A seventh
connection can be added in order to send an interrupt to the host CPU to inform that a new valid angle can be read. For additional information on
the layout and filtering of the SPI, please refer to Section 8.1.4 SPI Over Long Distances.
Figure 3. Typical Application Using SPI 4-Wire Mode and INT/ Output
4µ7
15 ohm
DC 3.0V ~ 3.6V
VDD
VDD
AS5055
Cordic
Interrupt
EN_INT/
Hall Sensors
SPI Interface
Power Management
VDDp
DC 1.8V ~ 3.6V
ADC
Supply: peripherals
INT/
µC
VDDp
VDDp
Wire
mode
SCK
Test_coil
MISO
VSS
MOSI
100n
SS/
SPI
Interface
Upon power-up, the AS5055 performs a full power-up sequence including one angle measurement. The completion of this cycle is indicated at
the INT/ output pin and the angle value is stored in an internal register. Once this output is low active, the AS5055 suspends to sleep mode.
7.1.1
Power Supply Filter
Due to the sequential internal sampling of the Hall sensors, fluctuations on the analog power supply (pin#12: VDD) may cause additional jitter of
the measured angle. This jitter can be avoided by providing a stable VDD supply.
The easiest way to achieve that is to add a RC filter: 15Ω + 4.7µF in the power supply line as shown in Figure 3.
Alternatively, a filter: 33Ω + 2.2µF may be used. However with this configuration, the minimum supply voltage is 3.15V.
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AS5055
Datasheet - D e t a i l e d D e s c r i p t i o n
7.1.2
Reading an Angle
The external microcontroller can respond to the INT request by reading the angle value from the AS5055 over the SPI interface. Once the angle
value is read, the INT output is cleared again.
Sending a “read angle” command by the SPI interface also automatically powers up the chip and starts another angle measurement. As soon as
the microcontroller has completed reading of the angle value, the INT output is cleared and a new result is stored in the angle register. The
completion of the angle measurement is again indicated by setting the INT output and a corresponding flag in the status register.
Reducing the Angle Jitter. Due to the measurement principle of the chip, only a single angle measurement is performed in very short time
after each power-up sequence. As soon as the measurement of one angle is completed, the chip suspends to power-down state. An on-chip
filtering of the angle value by digital averaging is not implemented, as this would require more than one angle measurement and consequently, a
longer power- up time which is not desired in low-power applications.
The angle jitter can be reduced by averaging of several angle samples in the external microcontroller. For example, an averaging of 4 samples
reduces the noise related jitter by 6dB (50%).
7.1.3
Low Power Mode
After completing the readout of an angle value, the device is in very low power condition. The AS5055 remains in sleep mode until it receives
another angle reading request over the SPI interface. The average power consumption therefore depends on the interval, at which the external
controller reads an angle over the SPI Interface. The timing ratio between active and sleep phase:
(EQ 1)
I avg =
ton ∗ I on + toff ∗ I off
ton + toff
Where:
ton = Minimum on-time for power-up and angle measurement
430µs
toff = Pause interval between measurements, determined by the polling rate of the external microcontroller
Ion = Current consumption in active mode
8.5mA (maximum)
Ioff = Current consumption in sleep mode
3µA
Examples:
3000 measurements per second (continuous mode)
I = 8.5mA
1000 measurements per second
Iavg = 3.7mA
100 measurements per second
Iavg = 370µA
10 measurements per second
Iavg = 40µA
Note: Even in low power mode, the power supply must be capable of supporting the active current at least for the time Ton, until the AS5055
is suspended to sleep mode.
7.1.4
Interrupt Chaining
Every chip contains a configurable gate to combine its own internally generated interrupt signal with a signal applied externally over the XENINTpin. The INT-mode register is preset via an OTP register and can be overwritten by the SPI interface.
Case A.
Device A is set to mode 0
Device B is set to mode 0
The micro controller recognizes an interrupt if both devices signalize that the computation is finished.
Case B.
Device A is set to mode 0
Device B is set to mode 1
The micro controller recognizes an interrupt if one of the two devices signalize that the computation is finished.
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AS5055
Datasheet - D e t a i l e d D e s c r i p t i o n
Figure 4. Interrupt Chaining
XINT
0
&
1
=1
0
&
1
x_interrupt
XINT
otp
INT
mode
INT
mode
otp
x_interrupt
MUX
=1
XINT
XENINT
MUX
XENINT
AS5055 (Device A)
Micro
controller
AS5055 (Device B)
7.2 SPI Communication
The transmitted data consists of 14-bit data, an Error-Flag and a Parity bit. When writing data to the chip, the Error-Flag is not applicable. The
Parity is generated from the upper 15 bits and forms an even parity over the whole frame. The Error-Flag indicates that a failure occurred in a
previous transmission.
7.2.1
Command Package
Every command sent to the AS5055 is represented with the following layout.
Table 6. Command Package
Bit
MSB
14
13
12
11
10
9
RWn
7
6
5
4
3
2
1
Address <13:0>
Bit
RWn
Address
PAR
7.2.2
8
LSB
PAR
Description
Indicates read or write command
14-bit address code
Parity bit (EVEN)
Read Package (Value Read from AS5055)
The read frame always contains two alarm bits, the error and parity flags and the addressed data of the previous read command.
Table 7. Read Package
Bit
MSB
14
13
12
11
10
9
8
7
Data <13:0>
Bit
Data
EF
PAR
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6
5
4
3
2
1
LSB
EF
PAR
Description
14-bit addressed data
Error flag indicating a transmission error in a previous host
transmission
Parity bit (EVEN)
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AS5055
Datasheet - D e t a i l e d D e s c r i p t i o n
7.2.3
Write Data Package (Value Written to AS5055)
The write frame is compatible to the read frame and contains two additional bits, the don’t care and parity flag.
If the previous command was a write command a second package has to be transmitted.
Table 8. Write Package
Bit
MSB
14
13
12
11
10
9
8
7
6
5
4
3
2
Data <13:0>
Bit
Data
PAR
7.2.4
1
LSB
Don’t care
PAR
Description
14-bit data to write to former selected address
Parity bit (EVEN)
Register Block
Table 9. Register Block
Register
Bit
Mode
Reset Value
Bit
Description
R/W
0x00
<7:0>
The POR cell is deactivated when the value 0x5A is written
to this register (30µA reduction of current consumption)
W
0x000
<13:0>
Refer to SOFTWARE RESET Command on page 13
W
0x000
<13:0>
Inject a power on reset cycle
R
0x000
<13:0>
Refer to CLEAR ERROR FLAG Command on page 12
w
0x000
<13:0>
Refer to NOP Command on page 14
Power ON Reset (POR) Register - [0x3F22]
POR_OFF
8
Software Reset Register - [0x3C00]
software_reset
14
Master Reset Register - [0x33A5]
master_reset
14
Clear Error Flag Register - [0x3380]
clr_error_flag
14
No Operation Register - [0x0000]
NOP
14
Automatic Gain Control (AGC) Register - [0x03FF8]
6
R/W
0x20
<5:0>
Automatic gain control:
low values = strong magnetic field
high values = weak magnetic field
Angle Value
12
R
0x000
<11:0>
Measured angular value, 12-bit
Alarm LO
1
R
0
<12>
Alarm bit indicating a too high magnetic field, active HIGH.
Refer to Error Monitoring on page 14
Alarm HI
1
R
0
<13>
Alarm bit indicating a too low magnetic field, active HIGH.
Refer to Error Monitoring on page 14
AGC
Angular Data - [0x3FFF]
System Configuration Register 1 - [0x3F20]
resolution
2
R
‘00’
<13:12>
‘00’ indicates 12-bit resolution
chip ID
3
R
‘001’
<11:9>
Silicon version 001
R
0x000
<13:0>
Refer to Error Status Command on page 15
Error Status Register - [0x335A]
error_status
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AS5055
Datasheet - D e t a i l e d D e s c r i p t i o n
7.2.5
SPI Interface Commands
READ Command. For a single READ command two transmission sequences are necessary. The first package written to the AS5055 contains
the READ command (MSB high) and the address the chip has to access, the second package transmitted to the AS5055 device can be any
command the chip has to process next. The content of the desired register is available in the MISO register of the master device at the end of the
second transmission cycle.
Figure 5. READ Command
T COM
MSB
LSB
MOSI
MISO
MSB
LSB
READ
Next command
Response - 1
Response on
READ command
MSB
LSB
MSB
Transmission N
LSB
Transmission N + 1
WRITE Command. A single WRITE command takes two transmission cycles. The WRITE command can be verified by sending a NOP
command after the WRITE command. The Data will be send back during NOP command.
Figure 6. WRITE Command
TCOM
MSB
MOSI
LSB
MSB
WRITE
command
MISO
LSB
MSB
LSB
Next command
Old register
content
Transmission N
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MSB
DATA
Response -1
MSB
LSB
New register
content
LSB
Transmission N + 1
Revision 1.16
MSB
LSB
Transmission N + 2
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AS5055
Datasheet - D e t a i l e d D e s c r i p t i o n
CLEAR ERROR FLAG Command. The CLEAR ERROR FLAG command is implemented as READ command. This command clears the
ERROR FLAG which is contained in every READ frame. The READ data are 0x0000, which indicates a successful clear command.
Figure 7. CLEAR ERROR FLAG Command
TCOM
MSB
LSB
MOSI
MSB
CLEAR ERROR
FLAG
MISO
Next command
Response-1
MSB
LSB
0x 0000
LSB
MSB
Transmission N
LSB
Transmission N + 1
The package necessary to perform a CLEAR ERROR FLAG is built up as follows.
Table 10. CLEAR ERROR FLAG Command
Bit
MSB
14
13
12
11
10
9
8
7
6
5
4
3
2
1
LSB
1
1
1
0
0
1
1
1
0
0
0
0
0
0
0
PAR
CLEAR ERROR FLAG command
PAR
Possible conditions which force the ERROR FLAG to be set:
Wrong parity
Wrong command
Wrong number of clocks (no full transmission cycle or too many clocks)
Note: If the error flag is set to ‘high’ because of a communication problem the flag remains set until it will be cleared by an external command.
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AS5055
Datasheet - D e t a i l e d D e s c r i p t i o n
SOFTWARE RESET Command. The SOFTWARE RESET command is implemented as WRITE command. The bit ‘RES SPI’ of the DATA
package indicates if the SPI registers should be reset as well. The soft reset resets the digital part (‘RES SPI’ is set to one) as well as the OTP
memory. A new OTP memory auto-load is initiated and the reset values stored in the OTP memory are loaded into the configuration registers.
The command following the SOFTWARE RESET command can be any of the commands specified in this chapter.
After the data package is sent, the soft reset is generated. The fuses of the OTP memory are loaded into the registers and a new conversion
cycle will be started. If the device is in sleep mode the oscillator will be started first.
Figure 8. SOFTWARE RESET Command
TCOM
MSB
LSB
MOSI
MISO
MSB
LSB
SOFTWARE
RESET
command
DATA
Response -1
0x 0000
MSB
LSB
LSB
Next command
0x 0000
MSB
Transmission N
MSB
LSB
MSB
Transmission N + 1
LSB
Transmission N + 2
In order to invoke a software reset on the AS5055 the following bit pattern has to be sent.
Table 11. SOFTWARE RESET Command
Bit
MSB
14
13
12
11
10
9
8
7
6
5
4
3
2
1
LSB
0
1
1
1
1
0
0
0
0
0
0
0
0
0
0
PAR
SOFTWARE RESET command
PAR
Table 12. Data Package
Bit
MSB
14
13
12
11
10
9
8
7
Don’t care
5
4
3
2
1
RES SPI Don’t care
Bit
Description
RES SPI
If set to one, SPI registers are reset as well
Parity bit (EVEN)
PAR
6
LSB
PAR
1
1. After a power on reset, the OTP will be read and hence OTP related
registers are changed independent on the RES SPI flag.
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AS5055
Datasheet - D e t a i l e d D e s c r i p t i o n
NOP Command. The NOP command represents a dummy write to the AS5055.
Figure 9. NOP Command
TCOM
MSB
LSB
MOSI
MISO
MSB
LSB
MSB
LSB
NOP
NOP
Next command
Response -1
0x0000
0x0000
MSB
LSB
MSB
Transmission N
LSB
MSB
Transmission N + 1
LSB
Transmission N + 2
The NOP command frame looks like follows.
Table 13. NOP Command
Bit
MSB
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
LSB
NOP command (0x0000)
The chip’s response on this command is 0x0000 – if no error happens.
7.2.6
Error Monitoring
The correct operation and communication of the AS5055 is ensured by several particular error flags. Every read access is supported by an error
flag (EF) to indicate a transmission error. In addition a dedicated error status register is accessible. See Table 14 on page 15.
Alarm HI
Alarm LO
0
0
Mode Description
AGC level is higher than the minimum value and lower than the maximum value
0
1
AGC level is equal or even lower than the minimum level
1
0
1
1
AGC level is equal or even higher than the maximum level
Indicates if any error flag has occurred. For detailed information, refer to Error
Status Command on page 15.
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AS5055
Datasheet - D e t a i l e d D e s c r i p t i o n
Error Status Command.
Table 14. Error Status Command
Description
Bit
Type
Error Status DSP
13
12
11
10
Error Status System
9
8
7
6
5
4
Error Status SPI
3
2
1
0
reserved DSPAHI DSPALO RANERR DSPOV DACOV reserved MODE WOW reserved ADDMON CLKMON PARITY
PARITY: Indicates when the transmitted parity bit does not match to calculated parity bit
CLKMON: Clock monitoring indicates when the amount of clock cycles is not correct
ADDMON: Address monitoring appears when the address does not exist
WOW: This is a handshake mechanism to check system integrity. By sending a READ ANGLE command the internal flag (WOW) is set to high.
At the end of measurement the WOW is set to low again. In failure case (internal dead lock situation) the WOW flag remains high.
MODE: During sleep mode, the flag is 0. When the IC is busy (measuring), the flag is 1.
DACOV: The DACOV bit occurs if the magnetic input field strengths is too large for at least one Hall element. This can be the case if the magnet
is displaced.
DSPOV: CORDIC overflow occurs when the input signals of CORDIC are too large
RANERR: Range error appears when the voltage drop over the internal current source decreases which is caused by increased temperature.
The accuracy is getting worse.
DSPALO: DSP Alarm LO; AGC level is equal or even lower than the minimum level.
DSPAHI: DSP Alarm HI; AGC level is equal or even higher than the maximum level.
For additional information on Error Status, please refer to the application note AN5000_Error Monitoring.
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Revision 1.16
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AS5055
Datasheet - A p p l i c a t i o n I n f o r m a t i o n
8 Application Information
The benefits of the AS5055 device are as follows:
Complete system-on-chip
Low power consumption
Low operating voltage
Easy to use
SPI interface
8.1 SPI Interface
The 16-bit SPI Interface enables read / write access to the register blocks and is compatible to a standard micro controller interface. The SPI
module is active as soon as /SS pin is pulled low. The AS5055 then reads the digital value on the MOSI (master out slave in) input with every
falling edge of SCK and writes on its MISO (master in slave out) output with the rising edge. After 16 clock cycles /SS has to be set back to a high
status in order to reset some parts of the interface core. The SPI Interface can be set in two different modes: 3-wire mode or 4-wire mode.
Notes:
1. The wire mode selection is read during the POWER-UP state and can be changed with a power on reset or a software reset command.
2. For more stability on the SPI Interface, it is very important to place filters. The filter must be placed close to the driving outputs. For
further information, please refer to the application note AN5000_SPI_Interface.
Table 15. Wire Mode Selection
Wire Mode Selection (pad 14)
8.1.1
wire_mode = LO
3-wire mode
wire_mode = HI
4-wire mode
SPI Interface Signals (4-Wire Mode, Wire_mode = 1)
The AS5055 only supports slave operation mode. Therefore SCK for the communication as well as the /SS signal has to be provided by the test
equipment. The following picture shows a basic interconnection diagram with one master and an AS5055 device and a principle schematic of the
interface core.
Figure 10. SPI Interface Connection
SCK
SPI_CLK
SS/
SPI_SSN
MOSI
MOSI
RXSR
Interface Core
Master Device
RXSPI
TXSPI
(Tester)
TXSR
MISO
MISO
AS5055
Because the interface has to decode the sent command before it can react and provide data the response of the chip to a specific command
applied at a time T can be accessed in the next transmission cycle ending at T + TCOM.
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AS5055
Datasheet - A p p l i c a t i o n I n f o r m a t i o n
The data are sent and read with MSB first. Every time the chip is accessed it is sending and receiving data.
Figure 11. SPI Command / Response Data Flow
TCOM
MSB
MOSI
MISO
LSB
MSB
MSB
LSB
MSB
LSB
Command 1
Command 2
Command N - 1
Command N
0x 00
Response 1
Response 2
Response N - 1
MSB
LSB
MSB
Transmission 1
8.1.2
LSB
LSB
MSB
Transmission 2
LSB
MSB
Transmission N - 1
LSB
Transmission N
SPI Timing
Figure 12. SPI Timing Diagram
t XSSH
SS /
( Input )
tL
t sck
t sckL
t sckH
tH
SCK
( Input )
t MISO
t OZ
MISO
( Output )
data[ 15]
data[ 14]
data[0]
t OZ
t MOSI
MOSI
( Input )
data[ 15]
data[ 14]
data[0]
Table 16. SPI Timing Characteristics
Parameter
Description
tOZ
Time between positive edge of SS/ to output high impedance
tL
Time between SS/ falling edge and SCK rising edge
10
ns
tSCK
Serial clock period
100
ns
tSCKL
Low period of serial clock
50
ns
tSCKH
High period of serial clock
50
ns
tH
Time between last falling edge of SCK and rising edge of SS/
tSCK / 2
ns
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Min
Revision 1.16
Max
Unit
50
ns
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AS5055
Datasheet - A p p l i c a t i o n I n f o r m a t i o n
Table 16. SPI Timing Characteristics
8.1.3
Parameter
Description
Min
Max
Unit
tXSSH
High time of SS/ between two transmissions
50
ns
tMOSI
Data input valid to clock edge
20
ns
tMISO
SCK edge to data output valid
20
ns
SPI Connection to the Host µC
Single Slave Mode.
Figure 13. Single Slave Mode
UC
MOSI
MOSI
MISO
MISO
SCK
SCK
SS/
SS/
1
0xFFFF
Write CMD
MOSI Read
angle 1
AS5055
Wire_Mode
0xFFFF
0xFFFF
Write CMD
Write CMD
Read angle 2 Read angle 3
Angle 1
MISO
Angle 2
0xFFFF
0xFFFF
0xFFFF
Write CMD
Write CMD
Write CMD
Read angle 4 Read angle 5 Read angle 6
Angle 3
Angle 4
Write CMD
NOP
Angle 5
...
Angle 6
SS/
4 wire mode
1
UC
MOSI
MISO
MISO
SCK
SCK
SS/
MISO
AS5055
Angle 1
Angle 2
Angle 3
Angle 4
Angle 6
Angle 7
0xFFFF
Write CMD
Read angle 4
Angle 4
Angle 5
SS/
1
SISO
Wire_Mode
SCK
SCK
SS/
SS/
0
3 wire mode (Read only )
0xFFFF
Write CMD
SISO Read
angle 1
MISO
MOSI
UC
...
SS/
AS5055
Angle 1
0xFFFF
Write CMD
Read angle 2
Angle 2
0xFFFF
Write CMD
Read angle 3
Angle 3
SS/
3 wire mode ( Bi - dir)
Wire_Mode
Note: 3 Wire Mode (read only): If the ERROR FLAG is set the device must be externally reset.
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AS5055
Datasheet - A p p l i c a t i o n I n f o r m a t i o n
Multiple Slave, n+3 Wire (Separate ChipSelect).
Figure 14. Multiple Slave, n+3 Wire (Separate ChipSelect)
UC
MOSI
MOSI
MISO
MISO
SCK
SCK
SS1/
SS/
SS2/
1
Write CMD
SW reset
UC MOSI
AS5055
I
Wire_ Mode
0xFFFF
Write CMD
Read angle1
...
UC MISO
xx
0xFFFF
Write CMD
Read angle 2
Angle 1
0xFFFF
Write CMD
Read angle 3
xx
Angle 2
0xFFFF
Write CMD
NOP
xx
Angle 3
SS1/
SS2/
SS3/
SS2/
MOSI
MISO
SCK
SS/
1
AS5055
II
Wire_ Mode
MOSI
MISO
SCK
SS /
1
AS5055
III
Wire_ Mode
Daisy Chain, 4 Wire.
Figure 15. Daisy Chain, 4-Wire
UC
MOSI
MOSI
MISO
MISO
SCK
SCK
SS/
SS/
1
CMD
UC MOSI Write
SW reset
AS5055 UC MISO
I
SS/
SCK
SS/
0xFFFF
0xFFFF
0xFFFF
0xFFFF
UC MOSI Read angle3 Read angle2 Read angle1 Read angle3 Read angle2 Read angle1
AS5055 UC MISO
II
SS/
Angle 3
Angle 2
Angle 1
...
...
...
Angle 3
Angle 2
Angle1
Wire_Mode
MOSI
MISO
SCK
SS/
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0xFFFF
Wire_Mode
MOSI
MISO
1
Write CMD
SW reset
...
0xFFFF
1
Write CMD
SW reset
AS5055
III
Wire_Mode
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AS5055
Datasheet - A p p l i c a t i o n I n f o r m a t i o n
8.1.4
SPI Over Long Distances
Over long cable distances you will have coupling capacitance between signals. Therefore consider some aspects.
The circuitry of the connection is shown in Figure 16.
Figure 16. Circuitry of SPI Over Long Distances
SPI Interface
µC
SPI Interface
AS5055
R
MOSI
C
MOSI
C
R
MISO
MISO
C
C
VSS
VSS
R
SCK
SCK
C
C
R
SS/
SS/
C
C
One aspect is that between MISO and SCK must be separated with VSS. Additionally filter circuitry, reduces the disturbance to a minimum.
Resistors close to the output pins reduce communication noise and increase EMC.
Required resistors on the output pins are between 100 Ohm and 1000 Ohm. Required capacitance is 100pF.
Place the resistors and capacitors as near as possible to the pins.
For additional information on this issue, please refer to the application note AS5055_SPI_APPNote.
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Revision 1.16
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AS5055
Datasheet - A p p l i c a t i o n I n f o r m a t i o n
8.2 Placement of the Magnet
Non-Linearity Error over Displacement.
As shown in Figure 18, the recommended horizontal position of the magnet axis is over the diagonal center of the IC.
Figure 17 shows a typical error curve at a vertical magnet distance of 1.0mm, measured with a NdFeB N35H magnet with 6mm diameter and
2.5mm height.
The X- and Y- axis of the graph indicate the lateral displacement of the magnet center with respect to the IC center.
At X = Y = 0, the magnet is perfectly centered over the IC. The total displacement plotted on the graph is for ±1mm in both directions.
The Z-axis displays the worst case INL error over a full turn at each given X-and Y- displacement. The error includes the quantization error of ±½
LSB. At the sample shown in Figure 17, the accuracy for a centered magnet is better than 0.5°. Within a radius of 0.5mm, the accuracy is about
1.0° (spec = 1.41° over temperature).
Figure 17. Integral Non-linearity Over Displacement of the Magnet
Non-Linearity @ z=1mm
4
3,5
3
2,5
2
INL [°] 1,5
1
0,5
0
3,5-4
0,8
-0,7
0,8
0,5
0,2
-0,4
-0,1
-0,4
-0,7
-1,0
0,2
X-displacement [mm]
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2,5-3
0,5
-0,1
-1,0
Revision 1.16
3-3,5
2-2,5
Y-displacement [mm]
1,5-2
1-1,5
0,5-1
0-0,5
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AS5055
Datasheet - P a c k a g e D r a w i n g s a n d M a r k i n g s
9 Package Drawings and Markings
The device is available in a 16-pin QFN (4x4x0.85 mm) package.
Figure 18. Drawings and Dimensions
YYWWXZZ
AS5055 @
Notes:
1. Dimensions and tolerancing conform to ASME Y14.5M-1994.
2. All dimensions are in millimeters. Angles are in degrees.
3. Dimension b applies to metallized terminal and is measured between 0.25mm
and 0.30mm from terminal tip. Dimension L1 represents terminal full back from
package edge up to 0.15mm is acceptable.
4. Coplanarity applies to the exposed heat slug as well as the terminal.
5. Radius on terminal is optional.
6. N is the total number of terminals.
Symbol
A
A1
A3
L
L1
b
D
E
e
D2
E2
aaa
bbb
ccc
ddd
eee
fff
N
Min
0.80
0
0.45
0
0.25
2.30
2.30
-
Nom
0.90
0.02
0.20 REF
0.50
0.30
4.00 BSC
4.00 BSC
0.65 BSC
2.40
2.40
0.15
0.10
0.10
0.05
0.08
0.10
16
Max
1.00
0.05
0.55
0.15
0.35
2.50
2.50
-
Marking: YYWWXZZ.
YY
WW
X
ZZ
@
Year (i.e. 04 for 2004)
Week
Assembly plant identifier
Assembly traceability code
Sublot identifier
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AS5055
Datasheet - P a c k a g e D r a w i n g s a n d M a r k i n g s
Figure 19. Vertical Cross Section of 16-pin QFN (4x4x0.85 mm)
Notes:
1.
2.
3.
4.
All dimensions in mm.
Die thickness 0.254 ± 0.013
Adhesive thickness 0.010 ± 10, +0.01, -0.0025
Lead frame thickness 0.203 typ.
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AS5055
Datasheet - R e v i s i o n H i s t o r y
Revision History
Revision
Date
Owner
1.0
23 Mar, 2010
jja
Initial revision of public release version
1.1
8 Jun, 2010
jlu
Updated Pin Descriptions (pin 16), Typical Application, SPI Connection to the
Host µC, Figure 3, Figure 13, Figure 14, Figure 15.
1.11
3 Nov, 2010
agt
Updated Absolute Maximum Ratings, System Parameters, Pin Descriptions,
Power Supply Filter, Table 9, SPI Connection to the Host µC, Package
Drawings and Markings.
1.12
3 Nov, 2011
mub
Updated operating temperature range.
1.13
28 Dec, 2011
1.14
11 Jul, 2012
1.15
16 Oct, 2012
1.16
05 Feb, 2013
21 Feb, 2013
rei
Description
Updated Figure 3, Table 9 and package drawings.
Updated Alarm LO / HI info in Table 9.
Updated Figure 1, Section 4, Section 7.2.4, Table 16; Added Error Status
Command, Figure 19, Section 8.1.4
ekno
Correction of error status register and alarm bits, updated marking.
Updated Table 4, Table 14, Table 16
Note: Typos may not be explicitly mentioned under revision history.
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Revision 1.16
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AS5055
Datasheet - O r d e r i n g I n f o r m a t i o n
10 Ordering Information
The devices are available as the standard products shown in Table 17.
Table 17. Ordering Information
Ordering Code
Description
Delivery Form
Package
AS5055 EQFT
12-bit low power magnetic rotary encoder
Tape & Reel
16-pin QFN (4x4x0.85 mm)
Note: All products are RoHS compliant and ams green.
Buy our products or get free samples online at www.ams.com/ICdirect
Technical Support is available at www.ams.com/Technical-Support
For further information and requests, email us at [email protected]
(or) find your local distributor at www.ams.com/distributor
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Revision 1.16
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AS5055
Datasheet - C o p y r i g h t s
Copyrights
Copyright © 1997-2013, ams AG, Tobelbaderstrasse 30, 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.
Disclaimer
Devices sold by ams AG are covered by the warranty and patent indemnification provisions appearing in its Term of Sale. ams AG makes no
warranty, express, statutory, implied, or by description regarding the information set forth herein or regarding the freedom of the described
devices from patent infringement. ams AG reserves the right to change specifications and prices at any time and without notice. Therefore, prior
to designing this product into a system, it is necessary to check with ams AG for current information. This product is intended for use in normal
commercial applications. Applications requiring extended temperature range, unusual environmental requirements, or high 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. For shipments of less than 100 parts the manufacturing flow might show deviations from the standard
production flow, such as test flow or test location.
The information furnished here by ams AG is believed to be correct and accurate. However, ams AG shall not be liable to recipient or any third
party for any damages, including but not limited to personal injury, property damage, loss of profits, loss of use, 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.
Contact Information
Headquarters
ams AG
Tobelbaderstrasse 30
A-8141 Unterpremstaetten, Austria
Tel
Fax
: +43 (0) 3136 500 0
: +43 (0) 3136 525 01
For Sales Offices, Distributors and Representatives, please visit:
http://www.ams.com/contact
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