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6-BIT MAGNETIC ANGULAR POSITION ENCODER WITH SERIAL INTERFACE
Key Features
u Up to 64 positions within 360 u Non contact switching u Simple magnet as rotary encoder u Zero position programmable (independent of
magnet orientation)
u Synchronous Serial Interface (SSI) u Cascading is possible u Chip Select Input u Small 8-Pin SOIC (SMT) Package u Temperature Range: -40C ...+85C
Ordering Information 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.
60
0... initial
4
56
52
N S
8
12
48
44
16
20
40
36
24
Functional Block Diagram
32 4mm
28
Rev. n/c
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Feb 2001
6-Bit Magnetic Position Encoder -Data Sheet Rev.1.0
AS5020
Pin Description Pin # 1 Symbol DATA Type DO Description 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. Positive Supply Voltage. Negative Supply Voltage (GND). 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. Not Connected during operation. This pin is used for testing purposes. Not Connected during operation. This pin is used for testing purposes. 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. CLOCK Input of the SSI. This pin is used to serially clock out the measured angle data at Pin 7 (DATA).
AI: Analogue Input OTP: One Time Programmable
2 3 4
VDD VSS PROG
AI AI DI
5 6 7
N.C. N.C. PD/CS
AI AI DI
8
CLK
DI
DI: Digital Input DO: Digital Output MSB: Most Significant Bit LSB: Least Significant Bit Note: The pins 5 and 6 must not be connected!
Pin Configuration
DATA VDD VSS PROG Rev. n/c Page 2/11
CLK PD/CS N.C. N.C. 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 Controller 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.
3mm
S
N
B/mT 30 S -30 180 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
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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.
PD/CS
1 2 7
Reset not necessary in Continuos Mode
8
9
CLK DATA
Latch actual value D5
(MSB)
D4
D0
NVR
Parity Next value
D5
(MSB)
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
C 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
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Feb 2001
6-Bit Magnetic Position Encoder -Data Sheet Rev.1.0
AS5020
PD/CS
1 2 7 8 9
CLK DATA
Latch actual value D5 D4 D0 NVR Parity D5 D4 D0 NVR Parity angle n Next value D5
angle 1
angle 2
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#;928s 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]
Initialisation
8
Zero Position Programming
Optional
tProgEN
Enable Programming
0 Dummy Bit 0 Bit 1 Bit 2 Bit 3 Bit 4 Bit 5 1 2 3 4 5 6 7 8
Calibration Position Latched
Cont. Mode
t
CS
Figure 4 Programming sequence Note: Daisy Chain configuration is not possible in Continuous Read Out Mode.
Measurement Enable
Rev. n/c
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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 +125C 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 VDD TAMB VIL VIH Parameter Supply Voltage Ambient Operating Temp. Range Input Low Voltage Input High Voltage** Conditions Measurement mode, VSS = 0 V Min. 4.5 -40 VSS 0.7 VDD Typ.* 5.0 25 Max. 5.5 +85 0.3 VDD VDD Unit V C V V
* Typical figures are at 25C 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 VPROG tZAP tProgEN tLH Parameter Programming Voltage Zap pulse duration Delay after CS=1 Pulse slew rate Conditions Min. 8 4.5 200 2 5 Typ. Max. 8.5 5.5 Units V s s V/s
DC Characteristics
Symbol IDD IDD0 IOL * Parameter Operating Supply Current Power Down Current Output Current, Sink Conditions Continuous Read Out Mode* PD/CS=1 VOL = 0.4V Min. 15 0.5 1 Typ. Max. 24 1 Units mA mA mA
Note: IDD in Single Read Out Mode is the same during the measurement phase
Rev. n/c
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Feb 2001
6-Bit Magnetic Position Encoder -Data Sheet Rev.1.0
AS5020
Timing Characteristics
Symbol tSetUp tReset tmeas tclkDATA tlatch TCLK Parameter Set up time after power on Minimum reset duration Min. waiting time for a single measurement * Max. CLK-DATA valid delay Min. Hold time after latching Data shift clock periode 5 1 Conditions Min. 20 1 20 10 Typ. Max. Unit s s s ns s us
Vdd PD/CS CLK DATA
tSetUp tReset tmeas tlatch
D5
D4
D3
D2
D1
D0
NVR
Parity
TCLK tclkDATA
Figure 5 Timing Characteristics Single Read Out Mode
Vdd PD/CS 1 CLK 2 3 4 5 6 7 8 9 1 2 3
DATA tSetUp
MSB
LSB
NVR
Parity
MSB
Figure 6 Timing Characteristics Continuous Read Out Mode
*Note: Multiple latching of 1 measured value in Continuous Read Out Mode is possible due to internal anticollision of the Value Update.
Rev. n/c
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Feb 2001
6-Bit Magnetic Position Encoder -Data Sheet Rev.1.0
AS5020
Magnetic Input Characteristics*
Symbol Bmin-max Off mag DistFmag Parameter Processing magnetic field strength input range Magnetic Offset Magnetic distortion factor Sinusoidal magnetic field density along 3mm concentric circle. 2 Conditions At package surface Min. 30 Typ. 40 Max. 50 5 3 Units mT mT %
Td D f
Magnet Temperature drift Diameter of encoder magnet Input frequency Both directions 3
-0.035 6 30000
%/K mm rpm
*Note: Please ask for our preferred Magnet Supplier List.
Output Characteristics
Symbol RES LSB INL DNL Parameter Resolution Minimum step Integral Non-Linearity Differential Non-Linearity See Note 1) Conditions Min. Typ. 6 5.625 0.5 0.5
No missing codes guaranteed
Max.
Units bits deg LSB LSB
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
6 b it
2 1 0
5 .6 2 5 32
0 0 180 360
Figure 5 Output value versus input angle
Rev. n/c
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Feb 2001
6-Bit Magnetic Position Encoder -Data Sheet Rev.1.0
AS5020
Magnet Placement
Symbol RDisp Parameter Displacement radius of rotational axis with reference to pins Distance between permanent magnet and package surface Conditions Magnet centered on rotational axis With reference magnet (depends on used magnet;) 1 Min. Typ. Max. 250 Units m
ZDist
mm
ZDist
RDisp Referenced to pins RDisp
Rev. n/c
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Feb 2001
6-Bit Magnetic Position Encoder -Data Sheet Rev.1.0
AS5020
Typical Application Areas
Non Contact Rotary Switch:
Position Control Isolated Switching Rotation Detection and many more
4, 8,16,32 Position Rotary Switch n of 64 Position Rotary Switch Digital Potentiometer, Dimmer 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 C Address Decoder
2
PD/CS PROG AS5020 CLK DATA
1 Programming
PD/CS PROG AS5020 CLK DATA
Parallel
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
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Feb 2001
6-Bit Magnetic Position Encoder -Data Sheet Rev.1.0
AS5020
Headquarters:
Austria Mikro Systeme International AG Schlo Premstatten A-8141 Unterpremstatten, Austria Tel: +43 (3136) 500-0 Fax: +43 (3136) 525 01, 536 50 email: info@amsint.com http: www.amsint.com
Sales Offices:
Germany: Tegernseer Landstrasse 85 D-81539 Munchen Tel.: +49 (89) 69 36 43-0 Fax: +49 (89) 69 36 43-66 Wilhelm-Busch-Platz 1 D-22850 Hamburg/Norderstedt Tel.: +49 (40) 522 80 13 Fax: +49 (40) 522 80 99 Amselweg 8 D-72820 Sonnenbuhl Tel.: +49 (7128) 92 71 28 Fax: +49 (7128) 92 71 40
France: 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: +44 (1276) 29 3 53
USA: Suite 300 4030 Wake Forest Road Raleigh NC27609 Tel.: +1 (919) 349 7551 Fax: +1 (509) 696 2713
Sweden: Sjoangsvagen 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 (c) 2001, Austria Mikro Systeme International AG, Schloss Premstatten, 8141 Unterpremstatten, Austria. Trademarks Registered (R). 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

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