AMSCO AS5020T

6-BIT MAGNETIC
ANGULAR POSITION ENCODER
WITH SERIAL INTERFACE
Key Features
❑ Up to 64 positions within 360°
❑ Non contact switching
❑ Simple magnet as rotary encoder
❑ Zero position programmable (independent of
magnet orientation)
❑ Synchronous Serial Interface (SSI)
❑ Cascading is possible
❑ Chip Select Input
❑ Small 8-Pin SOIC (SMT) Package
Ordering Information
❑ Temperature Range: -40°C ...+85°C
Part Number Package
AS5020
SOIC 8
AS5020T
SOIC8 Tape and Reel
General Description
The device provides the absolute angular position of a simple magnet that is placed under or
above the device’s surface. The device includes the Hall Sensor Array, signal conditioning and
post processing needed to generate a 6-bit binary code. The binary code can be easily
accessed by a Synchronous Serial Interface (SSI). The angle between the device and the
magnetic polarisation axis is exactly represented by one of 64 sectors (of 5.625° each) in the
full 360° range. Zero-Position Programming allows one time programming of a specific zero
position between the device and the magnet. The initial zero position is shown below.
0... initial
60
4
α
56
52
8
12
N
48
16
S
20
44
40
24
36
32
4mm
Functional Block Diagram
Rev. n/c
Page 1/11
28
Feb 2001
6-Bit Magnetic Position Encoder –Data Sheet Rev.1.0
AS5020
Pin Description
Pin #
Symbol
Type
Description
1
DATA
DO
DATA Output of the SSI.
If PD/CS=0, the measured angle data (6bit value) is serially
shifted out over this pin by the CLK, starting with the MSB. A
NVR Bit and a Parity bit are added. (NVR=1 indicates a NonValid Range of the magnetic field.) Even Parity is given.
2
VDD
AI
Positive Supply Voltage.
3
VSS
AI
Negative Supply Voltage (GND).
4
PROG
DI
PROGramming Input.
This pin is used to program the zero position into a non-volatile
memory (OTP). The programmed value is subtracted from the
actual measured angle.
5
N.C.
AI
Not Connected during operation. This pin is used for testing
purposes.
6
N.C.
AI
Not Connected during operation. This pin is used for testing
purposes.
7
PD/CS
DI
Power Down Input, Disable or Chip Select (active low).
PD/CS=0 activates the device and enables the measurement.
PD/CS=1 sets the device in power save mode and puts the
DATA pin in high impedance (highZ) state.
8
CLK
DI
CLOCK Input of the SSI.
This pin is used to serially clock out the measured angle data at
Pin 7 (DATA).
DI: Digital Input
DO: Digital Output
MSB: Most Significant Bit
LSB: Least Significant Bit
Note: The pins 5 and 6 must not be connected!
AI:
Analogue Input
OTP: One Time Programmable
Pin Configuration
DATA
Rev. n/c
CLK
VDD
PD/CS
VSS
N.C.
PROG
N.C.
Page 2/11
Feb 2001
6-Bit Magnetic Position Encoder –Data Sheet Rev.1.0
AS5020
Functional Description
Measurement Principle
A hall sensor array is used to convert the magnetic field distribution above the chip surface into
a binary code.
Measurement is enabled by PD/CS=0. After each measurement a 6-bit value is latched, with
the first falling edge of the CLK, into an output shift register.
The measured data is accessible via a Synchronous Serial Interface (SSI) by any µController
System.
Ratiometric measurement techniques together with hall sensor conditioning circuitry allow
robust tolerance to magnet misalignment.
Permanent Encoder Magnet
A simple two-pole magnet, e.g. a standard cylindrical permanent magnet that is diametric
magnetised, is needed.
α
3mm
S
N
B/mT
30
S
-30
α/°
180°
N
360°
Magnetic Field strength of at least ±30mTp is required at the package surface.
Standard magnet materials like rare earth AlNiCo / SmCo5 or NdFeB are recommended.
Please enquire for distributor references.
Rev. n/c
Page 3/11
Feb 2001
6-Bit Magnetic Position Encoder –Data Sheet Rev.1.0
AS5020
Measurement Modes
Two measurement modes can be selected by programming:
1) Single Read Out Mode (default)
2) Continuous Read Out Mode (OTP option)
Chip Select must be active low (PD/CS=0) to enable measurement and bring the output DATA
out of high impedance state.
After a minimum measurement period, the first falling edge of CLK latches the actual measured
angular value. The following rising edges shift the data bits out of the DATA pin, beginning with
the most significant bit. An NVR bit and even parity bit are added to the 6 bit angular value. The
NVR bit indicates a non-valid range given by bad magnet positioning.
Reset not necessary in
Continuos Mode
PD/CS
1
2
7
8
9
CLK
D5
DATA
D4
D0
NVR
D5
Parity
(MSB)
(MSB)
Latch
actual value
Next
value
Figure 1 SSI read out
In Single Read Out Mode the start of a new measurement has to be initiated with a short pulse
at PD/CS of at least 1 clockcycle. The following falling edge of CLK latches a new measured
value.
If the OTP option Continuous Read Out Mode is chosen, repeated angle measurement is
enabled by PD/CS=0. After each read out sequence the output shift register is automatically
refreshed. Fast transmission of the angular data can be performed without pulsing PD/CS.
Daisy Chain Configuration
In Singe Read Out mode, cascading allows Daisy Chain structures to minimise the
interconnection lines. Connecting DATA with PROG of the cascaded Sensor (see Fig. 2) allows
the read out of n sensors with the use of only three wires. The measurement data is shifted in
this configuration through the devices
After n x 9 clock cycles each value of n sensors is visible at pin DATA of the first sensor device.
A new measurement can be started with the falling edge of CLK after a power down pulse at
PD/CS.
n
µC
AS5020
PROG DATA
CLK PD/CS
2
AS5020
PROG DATA
CLK PD/CS
1
AS5020
PROG DATA
CLK PD/CS
CLK
Power Down
Data In
Figure 2 Typical Daisy Chain Configuration
Rev. n/c
Page 4/11
Feb 2001
6-Bit Magnetic Position Encoder –Data Sheet Rev.1.0
AS5020
PD/CS
1
2
7
8
9
CLK
D5
DATA
Latch
actual value
D4
D0 NVR Parity
D5
angle 1
D4 D0
angle 2
NVR Parity
D5
Next
value
angle n
Figure 3 Daisy Chain read out
Zero Position Programming
A simple single pin programming allows changing the initial zero position. It is easy to program
permanently a new zero-reference into the internal OTP (one time programmable) ROM. This
allows a fast and economic magnet placement since the intrinsic orientation is not important.
Single Pin Programming is provided via the PROG pin. Fig.4 shows the typical programming
sequence needed for fixing the new zero position.
Zero Position Programming Sequence
Before calibration, the new zero position must be adjusted in measurement mode (PD/CS=0).
The rising edge of PD/CS gets the actual position and stores it internally for the permanent
programming. A high level at the PROG Pin during power-down (PD/CS=1) with a minimum
duration of 300 V#HQDEOHV#SURJUDPPLQJ1#$IWHU#RQH#LQLWLDO#GXPP\#ELW#SXOVH/#VL[#SXOVHV#RI#;928µs
select the latched position information and zap the reference value into the OTP ROM.
Continuous Read Out Mode Selection
An optional 9th pulse after the initialisation pulse, the dummy pulse, and the 6 data pulses can
be used to set Continuous Read Out Mode (see Fig.4).
PROG [V]
Zero Position Programming
Initialisation
Optional
8
tProgEN
Enable
Programming
1
2
3
Bit 0
Bit 1
4
5
6
7
8
Bit 4
Bit 5
0
Dummy
Bit 2
Bit 3
Calibration Position
Latched
Cont.
Mode
t
Measurement
Enable
CS
Figure 4 Programming sequence
Note: Daisy Chain configuration is not possible in Continuous Read Out Mode.
Rev. n/c
Page 5/11
Feb 2001
6-Bit Magnetic Position Encoder –Data Sheet Rev.1.0
AS5020
Electrical Characteristics
Absolute Maximum Ratings*
Supply Voltage ............................................................................................................... -0.3 ”#9DD ”#:9
Input Current ................................................................................................................................ 25 mA
Digital Input Voltage ......................................................................................... -0.3V ”#9IN ”#9DD + 0.3V
Electrostatic Discharge............................................................................................................+/- 1000V
Storage Temperature Range............................................................................................ -50 to +125°C
Total Power Dissipation ............................................................................................................. 150mW
*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.
Operating Conditions
Symbol
Parameter
Conditions
Min.
Typ.*
Max.
Unit
VDD
Supply Voltage
Measurement mode,
VSS = 0 V
TAMB
Ambient Operating Temp.
Range
VIL
Input Low Voltage
VSS
0.3 VDD
V
VIH
Input High Voltage**
0.7 VDD
VDD
V
4.5
5.0
5.5
V
-40
25
+85
°C
* Typical figures are at 25°C and are for design aid only; not guaranteed and not subject to production testing.
Note: External Buffer-Capacitance is needed: e.g. 4.7uF between the Supply-Pins.
** Note: At pin PROG a higher voltage (up to 8.5V) as defined for the zero position programming routine.
Programming Input see Figure 4
Symbol
Parameter
Conditions
Min.
Typ.
VPROG
Programming Voltage
8
tZAP
Zap pulse duration
4.5
tProgEN
Delay after CS=1
200
µs
tLH
Pulse slew rate
2
V/µs
5
Max.
Units
8.5
V
5.5
µs
DC Characteristics
Symbol
Parameter
Conditions
Min.
IDD
Operating Supply Current
Continuous Read Out
Mode*
IDD0
Power Down Current
PD/CS=1
IOL
Output Current, Sink
VOL = 0.4V
•
Typ.
Max.
Units
15
24
mA
0.5
1
mA
1
mA
Note: IDD in Single Read Out Mode is the same during the measurement phase
Rev. n/c
Page 6/11
Feb 2001
6-Bit Magnetic Position Encoder –Data Sheet Rev.1.0
AS5020
Timing Characteristics
Symbol
Parameter
Conditions
Min.
Typ.
Max.
Unit
tSetUp
Set up time after power on
20
µs
tReset
Minimum reset duration
1
µs
tmeas
Min. waiting time for a single
measurement *
20
µs
tclkDATA
Max. CLK-DATA valid delay
tlatch
Min. Hold time after latching
5
µs
TCLK
Data shift clock periode
1
us
10
ns
Vdd
PD/CS
CLK
DATA
D5
tSetUp
tReset tmeas tlatch
D4
D3
D2
D1
D0
NVR
Parity
TCLK tclkDATA
Figure 5 Timing Characteristics Single Read Out Mode
Vdd
PD/CS
1
2
3
4
5
6
7
8
9
1
2
3
CLK
MSB
DATA
LSB
NVR
Parity
MSB
tSetUp
Figure 6 Timing Characteristics Continuous Read Out Mode
*Note:
Rev. n/c
Multiple latching of 1 measured value in Continuous Read Out Mode is possible due to internal anticollision of the Value Update.
Page 7/11
Feb 2001
6-Bit Magnetic Position Encoder –Data Sheet Rev.1.0
AS5020
Magnetic Input Characteristics*
Symbol
Parameter
Conditions
Min.
Typ.
Max.
Units
Bmin-max
Processing magnetic field
strength input range
At package surface
30
40
50
mT
Off mag
Magnetic Offset
5
mT
DistFmag
Magnetic distortion factor
3
%
Td
Magnet Temperature drift
D
Diameter of encoder magnet
f
Input frequency
Sinusoidal magnetic field
density along 3mm
concentric circle.
2
3
-0.035
%/K
6
mm
Both directions
30000
rpm
*Note: Please ask for our preferred Magnet Supplier List.
Output Characteristics
Symbol
Parameter
Conditions
Min.
Typ.
RES
Resolution
6
bits
LSB
Minimum step
5.625
deg
INL
Integral Non-Linearity
DNL
Differential Non-Linearity
See Note 1)
Max.
Units
0.5
LSB
0.5
LSB
No missing codes guaranteed
TN
Transition-Noise
0.1
LSB
1) Linearity is defined in terms of end point fit and guaranteed by design, proved by simulated test signals
63
α
6 b it
2
1
0
5 .6 2 5 °
32
0
0°
180°
360°
α
Figure 5 Output value versus input angle
Rev. n/c
Page 8/11
Feb 2001
6-Bit Magnetic Position Encoder –Data Sheet Rev.1.0
AS5020
Magnet Placement
Symbol
Parameter
Conditions
Min.
RDisp
Displacement radius of
rotational axis with
reference to pins
Magnet centered on rotational
axis
ZDist
Distance between
permanent magnet and
package surface
With reference magnet (depends
on used magnet;)
Typ.
1
Max.
Units
250
µm
mm
ZDist
RDisp
RDisp
Referenced to pins
Rev. n/c
Page 9/11
Feb 2001
6-Bit Magnetic Position Encoder –Data Sheet Rev.1.0
AS5020
Typical Application Areas
Non Contact Rotary Switch:
„ Position Control
„ 4, 8,16,32 Position Rotary Switch
„ Isolated Switching
„ n of 64 Position Rotary Switch
„ Rotation Detection
„ Digital Potentiometer, Dimmer
„ and many more
„ Angular Encoding
Advantages:
• No switch contacts
• Long mechanical life time
• Digital output
Similar to Daisy Chain configuration
multiple devices can be connected over
a serial bus structure. In this
configuration the PROG pins can be
connected together and allows
simultaneous calibration.
Figure 6 Front Panel Control
Address
µC
Address
Decoder
Parallel
2
1 Programming
PD/CS PROG
AS5020
CLK DATA
PD/CS PROG
AS5020
CLK DATA
n
PD/CS PROG
AS5020
CLK DATA
CLK
Data IN
Figure 7 Serial Bus Structure
For your interest:
A demonstration board for the AS5020 is available. The board includes the AS5020, an encoder
magnet, Micro-Controller and LED Display to indicate the position. Please ask your local sales
office. Further information can be found at our web-page:
http://www.amsint.com/products/product/index.html
Rev. n/c
Page 10/11
Feb 2001
6-Bit Magnetic Position Encoder –Data Sheet Rev.1.0
AS5020
Headquarters:
Austria Mikro Systeme
International AG
Schloß Premstätten
A-8141 Unterpremstätten, Austria
Tel:
+43 (3136) 500-0
Fax:
+43 (3136) 525 01, 536 50
email: info@amsint.com
http:
www.amsint.com
Sales Offices:
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Tegernseer Landstrasse 85
D-81539 München
Tel.:
+49 (89) 69 36 43-0
Fax:
+49 (89) 69 36 43-66
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Tel.:
+49 (40) 522 80 13
Fax:
+49 (40) 522 80 99
Amselweg 8
D-72820 Sonnenbühl
Tel.:
+49 (7128) 92 71 28
Fax:
+49 (7128) 92 71 40
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124 Avenue de Paris
F-94300 Vincennes
Tel.:
+33 (1) 43 74 00 90
Fax:
+33 (1) 43 74 20 98
United Kingdom:
Coliseum Business Centre
Watchmoor Park
Camberley, Surrey
England GUIS 3YL
Tel.:
+44 (1276) 23 3 99
Fax:
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Raleigh
NC27609
Tel.:
+1 (919) 349 7551
Fax:
+1 (509) 696 2713
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Sjöängsvägen 7
S-19272 Sollentuna
Stockholm, Sweden
Tel.:
+46 (8) 754 93 95
Fax:
+46 (8) 754 45
ltaly:
Via Leone Tolstoi, 64
I-20146 Milano
Tel.:
+39 02 423 67 13
Fax:
+39 02 422 90 889
Japan:
Shin Yokohama Daini Center Bldg. 10F
3-19-5, Shin Yokohama
Kohoku-ku, Yokohama 222-0033
Tel.:
+81 (45) 474 0962
Fax:
+81 (45) 472 9845
Devices sold by Austria Mikro Systeme are covered by the warranty and patent idemnification provisions appearing in its Term of Sale. Austria Mikro Systeme
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. Austria Mikro Systeme 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 Austria Mikro Systeme 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 lifesupport or life-sustaining equipment are specifically not recommended without additional processing by Austria Mikro Systeme for each application
Copyright © 2001, Austria Mikro Systeme International AG, Schloss Premstätten, 8141 Unterpremstätten, Austria. 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. The information
furnished here by Austria Mikro Systeme is believed to be correct and accurate. However, Austria Mikro Systeme 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 Austria Mikro Systeme rendering of technical or other services.
Rev. n/c
Page 11/11
Feb 2001