iC-MA
ANGULAR HALL SENSOR / ENCODER
Rev B3, Page 1/18
FEATURES
APPLICATIONS
♦ Quadruple hall sensor array for error-tolerant adjustment
♦ Non-sensitive to magnetic stray fields due to differential
measurement technique
♦ Interpolator with a resolution of up to 256 angle steps per cycle
♦ Rotational speeds up to 60.000 rpm
♦ 4 buffered I/O stages for signal outputs
♦ Three configuration inputs for operating mode selection
♦ Analog operation modes:
- sine/cosine signals controlled to 2 Vpp
- triange or sawtooth signal with selectable amplitude
♦ Digital operation modes:
- A/B quadrature signals with Z index pulse
- Counter pulses for external binary counters
♦ Cascading of multiple iC-MA possible for chain operation
♦ Error signal output for detection of low magnetic field strength
♦ Additional operating modes with reduced power consumption
♦ Standby modus when not enabled
♦ DFN10 package and bare die for flip chip mounting available
♦ Extended temperature range of -40...+125 °C
♦
♦
♦
♦
♦
♦
Analog and digital angle sensors
Incremental angular encoders
Magnetic multiturn encoders
Potentiometer replacement
Contactless rotary switch
Commutation of brushless DC
motors
♦ Flow meter
PACKAGES
DFN10
4 x 4 mm²
Chip
2.74 x 1.94 mm²
BLOCK DIAGRAM
VDD
VDD
CFG1
SIN
SIN
A
I/O
DIG
8 BIT
VDD
COS
CFG2
HALL SENSOR
AMP
B
I/O
GAIN
VDD
2
SIN +COS
CFG3
2
iC-MA
C
I/O
GAIN CONTROL
D
NEN
VDD
VREF
MODE
SELECT
BIAS
REFH
AMPLITUDE
ERROR
CONTROL
I/O
VPHI
DIG/R
REFL
INTERFACE
GND
Copyright © 2009 iC-Haus
http://www.ichaus.com
iC-MA
ANGULAR HALL SENSOR / ENCODER
Rev B3, Page 2/18
DESCRIPTION
The CMOS device iC-MA consists of a quadruple hall
sensor array which has been optimized for the magnetic measurement of angles of rotation. This array
permits error-tolerant adjustment of the magnet, reducing assembly efforts. The integrated signal conditioning unit provides a differential sine/cosine signal
at the output. The sensor generates one sine cycle
per each full rotation of the magnet, enabling the angle to be clearly determined. At the same time the
internal amplitude control unit produces an regulated
output amplitude of 2Vpp regardless of variations in
the magnetic field strength, supply voltage and temperature. Furthermore, signals are provided which
enable the sensor amplitude to be assessed and also
report any magnet loss.
With the aid of the integrated 8-bit sine/digital converter the angle of rotation is determined from the
sine/cosine signals. This is output via an incremental
interface in a number of selectable resolutions. The
zero angle is indicated by an index pulse. The maximum resolution of 8-bit is maintained up to rotations
of 60,000 rpm.
The absolute angle of rotation can be converted back
to a linear analog output signal using the internal D/A
converter; here, output voltage limits can be set as
required using the external pins. Either a periodic
linear signal (sawtooth) or a delta voltage (triangle)
can be provided. iC-MA can be easily cascaded in
three different modes of chain operation so that several axes of rotation can be scanned. The angle positions of the individual axes can then be read via a
common bus.
Used in conjunction with a permanent magnet iCMA can act as an encoder system with an integrated
magnetic scanning feature. No further components
are required.
iC-MA
ANGULAR HALL SENSOR / ENCODER
Rev B3, Page 3/18
PACKAGES DFN10 according to the JEDEC standard
PIN CONFIGURATION - DFN10 4 mm x 4 mm
1
10
2
9
iC-MA
...
...yyww
3
4
1
2
3
4
5
6
7
8
9
10
8
7
5
PIN FUNCTIONS
No. Name Function
6
NEN
GND
CFG2
B
A
D
C
CFG3
VDD
CFG1
Enable Input, low active
Ground
Configuration Input 2
Bidirectional Input/Output B
Bidirectional Input/Output A
Bidirectional Input/Output D
Bidirectional Input/Output C
Configuration Input 3
+5 V Supply Voltage
Configuration Input 1
The Thermal Pad on the bottom of the package should be connected to Ground (GND) on the PCB.
Orientation of package label ( MA CODE ...) may vary.
PIN FUNCTIONS
No. Name Function
PIN CONFIGURATION - Die
2.74 mm x 1.94 mm
9
8
7
10
6
1
5
2
3
4
1
2
3
4
5
6
7
8
9
10
NEN
GND
CFG2
B
A
D
C
CFG3
VDD
CFG1
Enable Input, low active
Ground
Configuration Input 2
Bidirectional Input/Output B
Bidirectional Input/Output A
Bidirectional Input/Output D
Bidirectional Input/Output C
Configuration Input 3
+5 V Supply Voltage
Configuration Input 1
iC-MA
ANGULAR HALL SENSOR / ENCODER
Rev B3, Page 4/18
ABSOLUTE MAXIMUM RATINGS
Beyond these values damage may occur; device operation is not guaranteed.
Item
No.
Symbol
Parameter
G001 VDD
Supply voltage
G002 V()
Voltages at A, B, C, D, NEN, CFG1,
CFG2
G003 Imx(VDD)
Conditions
V() < VDD + 0.3 V
Unit
Min.
Max.
-0.3
6
V
-0.3
6
V
Current at VDD
-30
30
mA
G004 Imx(GND) Current at GND
-30
30
mA
G005 Imx()
Current at A, B, C, D, NEN, CFG1,
CFG2
-10
10
mA
G006 Ilu()
Pulse current (Latch-up immunity)
Pulse width < 10 µs
-100
100
mA
G007 Vd()
ESD-Voltage at all pins
HBM 100 pF discharged over 1.5 kΩ
2
kV
G008 Ts
Storage temperature
150
°C
-40
THERMAL DATA
Operating conditions: VDD = 5 V ±10 %
Item
No.
Symbol
Parameter
Conditions
Unit
Min.
T01
Ta
Ambient temperature
T02
Rthja
Thermal resistance chip/ambient
-40
DFN10 on multi-layer test board acc. JEDEC
standard
All voltages are referenced to ground unless otherwise stated.
All currents into the device pins are positive; all currents out of the device pins are negative.
Typ.
Max.
125
°C
200
K/W
iC-MA
ANGULAR HALL SENSOR / ENCODER
Rev B3, Page 5/18
ELECTRICAL CHARACTERISTICS
Operating conditions: VDD = 5 V ±10 % , Tj = -40 ... 125 °C, unless otherwise noted
Item
No.
Symbol
Parameter
Conditions
Unit
Min.
Typ.
Max.
5
5.5
V
14
7
21
14
mA
mA
200
µA
General
001
002
VDD
Supply voltage
I(VDD)
Supply current
open pins, normal operation
open pins, power reduction mode (PRM)
4.5
003
I(VDD)sb
Standby supply current
NEN = VDD
004
td(VDD)on Turn on delay
VDD > 4 V, see figure 6
10
µs
005
td(VDD)off Turn off delay
VDD < 2.6 V
10
µs
Hall sensor array
101
Hext
Requiered external magnetic field at chip surface
strength
20
50
100
102
dsens
Diameter of Hall sensor array
see figure 1
103
xdis
Displacement of Hall sensor
array to package
DFN10 package, see figure 1
104
Φdis
Angular displacement of chip with DFN10 package
reference to package
105
hsens
Distance chip surface to top of
package
DFN10 package
106
Aabs
Absolute angular position
Using magnet with 4 mm diameter, centered to
chip, Hext = 20...100 kA/m
-3
3
DEG
on output, with external magnetic field amplitude of 20 kA/m
-50
50
mV
-50
50
µV/K
%VDD
2
kA/m
mm
-0.2
0.2
mm
-3
3
DEG
400
µm
Signal conditioning
201
Voff
Offset voltage
202
TC(Voff)
Temperatur coefficient of offset
voltage
203
Vdc
Output mean value
204
Ratio
Amplitude ratio of SIN / COS
205
fhc
Cut off frequency
206
t()settle
Settling time
207
V()gain
Gain output voltage
208
V()ampl
Sine/Cosine amplitude
45
50
55
0.95
1.00
1.05
20
to 70 % amplitude, Hext = 40 kA/m
80
0.05
V()ampl = V()max - Vdc
0.9
with reference to one periode, see fig. 2
-20
1.0
kHz
150
µs
4.0
V
1.1
V
20
%
Sine-to-digital converter
301
AArel
Relative angular error
302
f(OSC)
Oscillator frequency
303
TC(OSC)
Temperature coefficient of oscillator frequency
304
hys
Converter hysteresis
200
256
300
kHz
-0.1
%/K
1
LSB
Configuration inputs CFG1, CFG2, CFG3
401
Vt()hi
Threshold voltage high
60
78
% VDD
402
Vt()lo
Threshold voltage low
25
40
% VDD
403
V0()
Open circuit voltage
43
57
% VDD
404
Ri()
Input resistance
45
750
kΩ
2
V
250
mV
-25
µA
V
150
Enable input NEN
501
Vt()hi
Threshold voltage high
502
Vt()lo
Threshold voltage low
503
Vt()hys
Hysteresis
Vt()hys = Vt()hi - Vt()lo
100
504
Ipu()
Pull-up current
V() = 0...VDD - 1 V
-240
0.8
V
-120
Digital outputs: A, B, C, D
601
Vs()hi
Saturation voltage high
Vs()hi = VDD - V(), I() = -4 mA
0.4
602
Vs()lo
Saturation voltage low
I() = 4 mA
0.4
V
603
tr()
Rise time
CL() = 50 pF
60
ns
604
tf()
Fall time
CL() = 50 pF
60
ns
605
Ilk()
Leackage current
NEN = high, V() = 0 ... VDD
5
µA
-5
iC-MA
ANGULAR HALL SENSOR / ENCODER
Rev B3, Page 6/18
ELECTRICAL CHARACTERISTICS
Operating conditions: VDD = 5 V ±10 % , Tj = -40 ... 125 °C, unless otherwise noted
Item
No.
Symbol
Parameter
Conditions
Unit
Min.
Typ.
Max.
606
Vc()hi
Clamp voltage high
Vc()hi = V() - VDD, NEN = high, I() = 4 mA
0.3
1.6
V
607
Vc()lo
Clamp voltage low
NEN = high, I() = -4 mA
-1.5
-0.3
V
2
V
Digital inputs: A, B, C, D
701
Vt()hi
Threshold voltage high
702
Vt()lo
Threshold voltage low
703
Vt()hys
Hysterese
Vt()hys = Vt()hi - Vt()lo
704
Ipd()
Pull-down current
V() = 1 V...VDD
0.8
V
300
mV
5
30
65
µA
Analog outputs: A, B, C, D
801
SR
Slew Rate
802
fhc()
Cut off frequency
2
803
I()
Output current
804
R()eda
Input resistance DA-converter
between pin B and pin C
805
R()ada
Output resistance DA-converter
at pin A
V/µs
500
kHz
-1
6
8
1
mA
10
kΩ
kΩ
hsens
100
0%
twhi()/T
dsens
50%
AArel
0%
100%
AArel
Figure 1: Location of die in DFN10 package
Figure 2: Definition of relative angular error
iC-MA
ANGULAR HALL SENSOR / ENCODER
Rev B3, Page 7/18
OPERATING CONDITIONS: Logic
Operating conditions: VDD = 5 V ±10 %, Tj = -40...125 °C, unless otherwise noted
Input level low = 0...0.45 V, high = 2.4 V...VDD, timing according Fig. 3
Item
No.
Symbol
Parameter
Conditions
Unit
Min.
Max.
Logic
I001 ts(NEN)
Setup time NEN
CLK : low → high (see figure 12)
I002 tp(NEN)
Delay time NENO
CLK : high → low (see figure 12)
30
ns
I003 tp(SIG1)
Delay time SIG1
CL() = 50 pF (see figure 12)
60
µs
I004 tp(SIG2)
Delay time SIG2
CL() = 50 pF (see figure 12)
2
µs
I005 tp(CFGx)
Setup time at CFGx, x = 1..3
see figure 6
10
µs
30
V
Input/Output
2.4V
2.0V
0.8V
0.45V
t
1
0
Figure 3: Reference levels for delays
ns
iC-MA
ANGULAR HALL SENSOR / ENCODER
Rev B3, Page 8/18
The sensor principle
N
z
y
S
+Bz
B
x
-Bz
Figure 4: The principle of magnetic field measurement using a Hall sensor
In conjunction with a permanent magnet iC-MA can be
used to create a complete encoder system. A cylindri-
cal, diametrically magnetized permanent magnet (with
a diameter D of 4 mm and length L of 4 mm, for example) provides optimal sensor signals. Magnetic materials such as neodymium iron boron (NdFeB) or samarium cobalt (SmCo) are very well suited to the sensor
and not readily influenced by external magnetic disturbance fields. The L/D ratio of a magnet magnetized
to saturation point has a bearing on the resulting field
strength and should lie within the region of 0.3 to 2.
iC-MA has four Hall sensors which are used to determine angles and to convert the magnetic field into a
measurable Hall voltage. Only the z component of the
magnetic field is assessed where the line of magnetic
flux must pass through two facing Hall sensors in the
opposite direction. An example line of magnetic flux
is given in Figure 4. The Hall sensors have been arranged in such a way that the assembly of the magnet with iC-MA is extremely tolerant. Two Hall sensors combined generate a differential Hall signal. If
the magnet is rotated along its longitudinal axis sine
and cosine output voltages are created which can be
used to determine angles.
iC-MA
ANGULAR HALL SENSOR / ENCODER
Rev B3, Page 9/18
Definition of the angle of rotation and the direction of rotation
The arrangement of permanent magnet and iC-MA illustrated in Figure 5, where the diametrically magnetized magnet is placed vertical to the chip’s surface, is
used to determine both the angle ω and direction of rotation. An angle of 0° lies along the diagonal. Rotating
the magnet clockwise as shown in Figure 5 increases
the angular position and hence the output signal.
N
S
N
S
0°
Figure 5: Definition of the angle and direction of rotation
Programming the configuration
iC-MA has 28 modes of operation (see tables on the
following pages). After the device has been switched
on or "woken up" from standby mode by a low signal at pin NEN the levels at the configuration inputs
CFG1 to CFG3 are assessed. These three-level inputs can be connected to GND (low), left open (open)
or connected to VDD (high). For correct identification,
a setup time of at least tp(CFGx) = 4 µs must be maintained between programming the configuration and activating the device. While the device is active changes
in signal at the configuration inputs are ignored.
If several iC-MAs are connected in series in chain operation (see the description of functions on page 13)
it must be ensured that the NEN input of the devices
is switched to low during the various clock cycles and
that the programming default does thus not lie within
the active phase of the devices.
In standby all ports are switched to tristate, i.e. high
impedance. Only in chain operation modes port D is
active high so that the devices arranged further behind
can also be deactivated.
4V
VDD
NEN
iC-MA active
iC-MA active
CFGx
td(VDD)on
tp(CFGx)
tp(CFGx)
Figure 6: Programming the configuration
iC-MA
ANGULAR HALL SENSOR / ENCODER
Rev B3, Page 10/18
Operating modes
Mode
NEN CFG1 CFG2
Analog
low
low
S-Sensor low
D-Sensor low open low
D-Sensor low high low
Linear output
R-Sensor low
low open
low open open
low high open
low high open
Chain-Mode
low high
AB-Chain low
D-Chain
low open high
S-Chain
low high high
Incr. ABZ
ABZ 8-1
low
low
low
ABZ 8-0
low open low
ABZ 7-1
low
low open
ABZ 7-0
low open open
ABZ 6-1
low
low high
ABZ 6-0
low open high
ABZ 8-1
low
low
low
ABZ 8-0
low open low
ABZ 7-1
low
low open
ABZ 7-0
low open open
ABZ 6-1
low
low high
ABZ 6-0
low open high
Incr. CLK
CLK 8
low high low
CLK 6
low high high
DIR 8
low high low
DIR 6
low high high
Test (for iC-Haus use only)
low high open
Test
Standby
high
x
x
1
CFG3
Port A
Port B
Port C
Port D
Res. Comments
low
low
low
PSIN
PSIN
PSIN
VREF
NSIN
NSIN
PCOS
PCOS
PCOS
GAIN
NCOS
NCOS
PRM
low
low
low
high
VTRI
VTRI
VSAW
VSAW
REFH
REFH
REFH
REFH
MSB
MSB
REFL
REFL
NERR
GAIN
NERR
GAIN
8
8
8
8
low
low
low
A
PSIN/NSIN
PSIN/VREF
CLK
CLK
CLK
B
PCOS/NCOS
PCOS/GAIN
NENO
NENO
NENO
8
open
open
open
open
open
open
high
high
high
high
high
high
A
A
A
A
A
A
A
A
A
A
A
A
B
B
B
B
B
B
B
B
B
B
B
B
Z
Z
Z
Z
Z
Z
Z
Z
Z
Z
Z
Z
NERR
NERR
NERR
NERR
NERR
NERR
NERR
NERR
NERR
NERR
NERR
NERR
8
8
7
7
6
6
8
8
7
7
6
6
open
open
high
high
NCLKUP
NCLKUP
NCLK
NCLK
NCLKDN
NCLKDN
DIR
DIR
NCLR
NCLR
NCLR
NCLR
NERR
NERR
NERR
NERR
8
6
8
6
open
x
AB=1
AB=0
AB=1
AB=0
AB=1
AB=0
AB=1, PRM
AB=0, PRM
AB=1, PRM
AB=0, PRM
AB=1, PRM
AB=0, PRM
Test
TRI
TRI
TRI
TRI1
In chain operation port D is active high so that the backend devices can also be deactivated.
iC-MA
ANGULAR HALL SENSOR / ENCODER
Rev B3, Page 11/18
Analog modes of operation
Mode
Analog
S-Sensor
D-Sensor
D-Sensor
NEN CFG1 CFG2 CFG3
low
low
low
low
open
high
low
low
low
low
low
low
Port A
Port B
Port C
Port D
Res. Comment
PSIN
PSIN
PSIN
VREF
NSIN
NSIN
PCOS
PCOS
PCOS
GAIN
NCOS
NCOS
PRM
In the analog modes of operation the amplified Hall
voltages are available at the output ports. The sine/
cosine output signals are controlled to have stable amplitudes of 1 V and referenced to a DC value equivalent
to half of the supply voltage (VREF). Due to the internal signal conditioning unit, no special adjustment is
required. An externally connected interpolator can be
used if further trimming of the output signals is desired.
5
Signal GAIN allows conclusions to be drawn as to the
operating point of the sensor. This is influenced by
the amplitude of the magnetic field, the sensor supply
voltage and temperature. The higher the GAIN potential, the greater the necessary amplification of the Hall
voltages; the external magnetic field is smaller. Besides recording the direction of magnetization of the
permanent magnet the distance between the magnet
and sensor may also be assessed using the GAIN signal. If the gain is insufficient to boost the Hall voltages
to 2 Vss the amplitude control reaches its upper limit
and the output amplitude becomes smaller.
4
Voltage [V]
PSIN
NCOS
The GAIN signal can be used to adjust the permanent
magnet. If the central point of both the magnet and
sensor iC-MA are the same the GAIN signal has no
harmonics. A misaligned sensor must readjust the operating point depending on the angle; the GAIN signal
varies in amplitude. To adjust the sensor to the magnet
this must be shifted along its X- and Y-axis so that the
GAIN signal has to readjust as little as possible.
3
VREF
2
PCOS
NSIN
1
GAIN
0
0
100
200
300
400
500
600
700
Time [µs]
Figure 7: Analog mode output signals after switching on the device
S sensor mode
After the device has been activated via NEN = low the
sensor is set to its operating point. All signals are referenced to half the supply voltage (VREF). In S sensor mode this potential is available at port B. Ports A
and C output the sine and cosine Hall voltages set to
2 Vss. The angle can be calculated from the relation of
the sine voltage (difference in voltage PSIN to VREF)
to the cosine voltage (difference in voltage PCOS to
VREF). The device supplies an angle which remains
non-ambiguous over a 360° rotation of the permanent
magnet.
D sensor mode
In D sensor mode differential sine (pin A and pin B) and
cosine (pin C and pin D) signals are supplied at the output; as opposed to S sensor mode inverted Hall signals
are now also available at the ports. The advantage of
this mode of operation is the doubled signal amplitude
of the differential Hall voltages and the lack of dependence on reference voltage VREF. The angle is now
calculated via the ratio of the difference between PSIN
and NSIN and between PCOS and NCOS.
D sensor mode is also available with a reduced power
consumption (PRM or Power Reduced Mode). In this
mode the Hall sensor is supplied with current less frequently, reducing the power consumption. Here it must
be observed that the maximum rotating frequency also
drops by a factor of 2.
iC-MA
ANGULAR HALL SENSOR / ENCODER
Rev B3, Page 12/18
Resistor modes of operation
Port A
Port B
Port C
Port D
VTRI
VTRI
VSAW
VSAW
REFH
REFH
REFH
REFH
MSB
MSB
REFL
REFL
NERR
GAIN
NERR
GAIN
Resistor modes of operation
In R sensor mode the taps of an integrated resistive
divider are selected depending on the angular position
("potentiometer replacement"). The value of the absolut angular position acts as a "wiper" and selects one
of the 256 taps on the resistor chain.
Res. Comments
8
8
8
8
5
REFH
4
Voltage [V]
Mode
NEN CFG1 CFG2 CFG3
Linear output
low open low
R-Sensor low
low open open low
low high open low
low high open high
3
VSAW
2
REFL
1
0
0
45
90
135
180
225
270
315
360
405
450
Angle [°]
Figure 8: Potentiometer equivalents for resistor
mode operations
Figure 9: R-Sensor mode with sawtooth output voltage VSAW
5
Modes of operation with a triangular voltage VTRI
avoids the discontinuity at the zero angular position.
Signal MSB can be used to differentiate between the
first and second half rotation. The delta voltage is limited by thresholds REFH and GND. As in VSAW mode
both GAIN and NERR signals are available.
REFH
4
Voltage [V]
In modes with a sawtooth voltage VSAW at port A
the angle is converted into a linear voltage which lies
within thresholds REFH and REFL at ports B and C
(see Figure 9). The integrated resistor chain is directly available at the ports so that thresholds REFH
and REFL can also be reversed. Depending on the
selected mode either a GAIN signal or a NERR error
signal are present at port D to monitor the amplitude.
If the amplitude is at least 70 %, NERR is high; should
the amplitude sink to below 50 % of the set amplitude,
NERR switches to active low.
3
2
VTRI
1
0
0
MSB
45
90
135
180
225
270
315
360
405
450
Angle [°]
Figure 10: R-Sensor mode with triangular output
voltage VTRI
iC-MA
ANGULAR HALL SENSOR / ENCODER
Rev B3, Page 13/18
AB chain, D chain and S chain modes
CFG1 CFG2 CFG3
low
open
high
high
high
high
low
low
low
Port A
Port B
Port C
Port D
A
PSIN/NSIN
PSIN/VREF
CLK
CLK
CLK
B
PCOS/NCOS
PCOS/GAIN
NENO
NENO
NENO
Res. Comments
8
CLK
MA 0
MA 1
CLK
NEN(0)
MA 2
CLK
NEN NENO
NEN(1)
iC-MA
CLK
NEN NENO
NEN(2)
NEN NENO
iC-MA
NEN(3)
iC-MA
A
A
A
C
C
C
A
C
Figure 11: Chain modes for iC-MA
CLK
ts(NEN)
NEN(0)
tp(NEN0)
NEN(1)
tp(SIG1) tp(SIG2)
ts(NEN)
B
PCOS0
NCOS0
MA 0 active
PCOS1
NCOS1
MA 1 active
PSIN2
PCOS2
NSIN2
NCOS2
MA 2 active
Figure 12: Signal patterns in D chain mode
TRISTATE
NSIN1
TRISTATE
PSIN1
TRISTATE
NSIN0
TRISTATE
PSIN0
TRISTATE
A
TRISTATE
NEN(3)
TRISTATE
NEN(2)
TRISTATE
Mode
NEN
Chain operation
AB chain low
D chain
low
S chain
low
iC-MA
ANGULAR HALL SENSOR / ENCODER
Rev B3, Page 14/18
In the various chain modes multiple iC-MAs can be arranged in a chain (see Figure 11) where all of the devices are connected by a shared CLK line (pin B). The
NEN input is evaluated synchronously with the rising
CLK edge. If the NEN input is switched to low, the
device is active during the following CLK cycle(s). To
allow the devices to be cascaded a delayed enable signal is generated at output pin NENO (pin D) with which
the follow-on device can be activated. If the NEN input of the first device in the chain is reset to high, all
devices in the chain are deactivated. Bus lines A (pin
A) and C (pin C) are activated by tristate output stages
which are high impedance when NEN is high and CLK
is low and also following the second rising CLK edge.
AB chain mode
In AB chain mode two A/B digital incremental signals
are generated at ports A and C. The two square-wave
signals are phase shifted at either +90° or -90°, depending on the direction of rotation. Following a CLK
pulse the next device in the chain is enabled. Here the
falling CLK edge deactivates the current device (e.g.
MA 1 in Figure 11) and activates the next device in the
chain (MA 2) with a low signal at its NEN input. After
a device has been activated the two bus lines A (port
A) and B (port C) are first switched to low (see Figure
12). This is then followed by the incremental signals
being output, starting at the zero position. In the event
of error the bus lines remain low.
second clock pulse deactivates the current device and
activates the following device in the chain with a low
signal at its NEN input.
S chain mode
In S chain mode the non-inverted sine (port A) and cosine (port C) signals are presented to the bus during
the first clock pulse, with the mean of the two signals
(VREF, port A) and the amplification signal GAIN (port
C) following on the positive CLK edge of the next pulse.
Each device is thus active for two clock pulses. The
falling CLK edge in the second clock pulse deactivates
the current device and activates the following device in
the chain with a low signal at its NEN input.
The sine and cosine signals can be assessed using
signal VREF. Signal GAIN (pin D) indicates iC-MA’s internal amplification (see Electrical Characteristics No.
207) and can be used to estimate the signal amplitude
of the internal Hall sensor. The GAIN signal can also
be used to adjust the rotary axis of the magnet to the
center of the chip.
NEN
CLK
NENO
D chain mode
In D chain mode differential sine and cosine signals
are generated at ports A and C. During the first clock
pulse signals PSIN and PCOS are presented to the
bus; during the second pulse signals NSIN and NCOS
are on the bus (see Figure 12). In this mode each
device is thus active for two clock pulses. During the
first clock pulse the non-inverted sine (port A) and cosine (port C) signals are first presented to the bus, with
the inverted signals following on the positive CLK edge
during the second pulse. The falling CLK edge in the
Voltage [V]
5
4
A
3
C
2
1
0
0
100
200
300
400
500
600
700
Time [µs]
Figure 13: Bus signals and control signals in S
chain mode
iC-MA
ANGULAR HALL SENSOR / ENCODER
Rev B3, Page 15/18
Incremental ABZ modes
Mode
NEN
Incr. ABZ
ABZ 8-1 low
ABZ 8-0 low
ABZ 7-1 low
ABZ 7-0 low
ABZ 6-1 low
ABZ 6-0 low
ABZ 8-1 low
ABZ 8-0 low
ABZ 7-1 low
ABZ 7-0 low
ABZ 6-1 low
ABZ 6-0 low
CFG1 CFG2 CFG3
low
open
low
open
low
open
low
open
low
open
low
open
low
low
open
open
high
high
low
low
open
open
high
high
open
open
open
open
open
open
high
high
high
high
high
high
Port A
Port B
Port C
Port D
A
A
A
A
A
A
A
A
A
A
A
A
B
B
B
B
B
B
B
B
B
B
B
B
Z
Z
Z
Z
Z
Z
Z
Z
Z
Z
Z
Z
NERR
NERR
NERR
NERR
NERR
NERR
NERR
NERR
NERR
NERR
NERR
NERR
iC-MA has an 8-bit sine/digital converter which can
convert the sine/cosine sensor signals into a digitized
angle. This angle is made available at the ports as an
incremental value. Signal Z is always high when the
angle is 0°; otherwise the signal is low. In all incremental modes of operation error signal NERR is available
so that the plausibility of the counter value can be verified. At an amplitude which is less than 50 % of the set
amplitude the error signal switches to low; at an amplitude greater than 70 % the error signal is reset, i.e. set
to high.
Three different quantities regarding the number of
edges per rotation of the magnet can be selected.
These are a resolution of 6 bits (64 edges per rotation), 7 bits (128 edges) or 8 bits (256 edges). The
conversion process is count-safe, i. e. the output of all
edges up to the current angle position is guaranteed as
long as the input frequency is less than the maximum
possible rotation.
All incremental resolutions also have a reduced power
consumption mode(PRM). In this mode the Hall sensor is supplied with current intermittently, reducing the
power consumption. Here it must be noted that the
maximum input frequency drops by a factor of 2.
Res. Comments
8
8
7
7
6
6
8
8
7
7
6
6
AB=1
AB=0
AB=1
AB=0
AB=1
AB=0
AB=1, PRM
AB=0, PRM
AB=1, PRM
AB=0, PRM
AB=1, PRM
AB=0, PRM
14). After switching on the sensor via NEN at low the
sensor looks for its operating point. If 70 % of the set
amplitude is achieved the error signal is reset. An error
status during this phase is also signaled when signals
A and B are high and Z low. In an error-free state Z
is always high when the angle is 0°. iC-MA continues
to search for its operating point by outputting the angle
of the external magnetic field at maximum count frequency via the incremental interface. Once the angle
has been obtained the device follows a changed input
signal in real time. The edge frequency is thus 256
times the frequency of rotation of the magnet at a set
resolution of 8 bits. If a (rising) edge reaches B before
a (rising) edge A, this means that the counter value
has risen. If the edge reaches A before B, however,
this indicates that the absolute value is lower.
NEN
NERR
A
A distinction can be made between the various modes
of operation by studying the level of the AB signals on
the Z pulse. In mode AB = 1 signals A and B are both
high, as is Z at an angle of 0°. In mode AB = 0, however, both signals A and B are low when the Z signal
is high.
B
Z
Time [us]
Firstly, the behavior of the sensor on switching on the
device is described when the permanent magnet rotates in the direction of the increasing angle ω (Figure
Figure 14: Incremental signals after switching on
the device, counting up
iC-MA
ANGULAR HALL SENSOR / ENCODER
Rev B3, Page 16/18
as possible. If this absolute angle is between 0° and
180° the device counts up to the operating point; if the
angle is between 180° and 360°, it first counts down.
Starting when the device is switched on all edges are
output until the absolute position is reached. The setup
has to wait until a certain time has elapsed; this is dependent on the selected resolution and is the settling
time of the sensor until the error bit is deleted plus the
time needed to count up or down to the absolute position. With a resolution of 8 bits and an angle of 180°,
for example, this period constitutes 100 µs sensor settling time plus 128 times 4 µs until the absolute position has been pinpointed. The absolute position is thus
available after a maximum of 612 µs has elapsed.
NEN
NERR
A
B
Z
Time [us]
Figure 15: Incremental signals after switching on
the device, counting down
Always starting at an angle of 0° the device begins
searching for the absolute angle, locating it as quickly
By way of example Figure 15 illustrates how the incremental interface behaves when the device first counts
down to the absolute position and the magnet then rotates forwards, with the sensor following with the relevant sequence. The Z signal is synchronous with A
and B at low.
Incremental CLK modes
Mode NEN CFG1 CFG2
Inkr. CLK
CLK 8 low high low
CLK 6 low high high
DIR 8 low high low
DIR 6 low high high
CFG3
Port A
Port B
Port C
Port D
open
open
high
high
NCLKUP
NCLKUP
NCLK
NCLK
NCLKDN
NCLKDN
DIR
DIR
NCLR
NCLR
NCLR
NCLR
NERR
NERR
NERR
NERR
CLK-INC mode
In CLK-INC mode two different count signals are
provided for the countup and countdown sequences.
Depending on the direction of rotation either signal
NCLKUP (pin A) is pulsed when the device counts
up or signal NCLKDN (pin B) when the device counts
down. In each case the remaining signal is high. The
zero angle is displayed by the NCLR index track which
can serve as an asynchronous reset for an external
counter.
Figure 16 demonstrates how iC-MA behaves in CLKINC mode, firstly when it counts up from the zero position and then, following a change in the direction of
rotation, when it counts back down to an angle of 0°.
Res. Comments
8
6
8
6
and a high at NCLKUP the counter status is decremented. Two 4-bit counters can be cascaded here to
create a full 8-bit counter.
NCLUP
NCLDN
NCLR
This mode permits the operation of external binary
counter modules (such as 74HC/HCT193, for example), with signal NCLR (pin C) being used to reset the
counter. With a rising edge of clock signal NCLKUP
and a high at NCLKDN the counter status is incremented; with a rising edge of clock signal NCLKDN
Time [us]
Figure 16: CLK-INC mode
iC-MA
ANGULAR HALL SENSOR / ENCODER
Rev B3, Page 17/18
DATA INPUT
VDD
P0
CFG1
NCLUP
CPU
CFG2
NCLDN
CPD
iC-MA
CFG3
NCLR
NEN
NERR
P1
P2
P3
74HCT193
CPU
TCD
CPD
MR
NPL
NPL
Q0
Q1
Q2
P0
TCU
Q3
P1
P3
P2
TCU
74HCT193
Q0
the value of the DIR signal. A low at DIR triggers a
countup; a high causes the setup to count down. Figure 17 shows a countup sequence followed by a countdown sequence, both across the zero position.
TCD
MR
Q1
Q2
Q3
RESET
GND
CLK
OUTPUT
Figure 17: iC-MA
with
74HC/HCT193
binary
counter
DIR-INC mode
In DIR-INC mode a change in angle for both directions
of rotation generates an output pulse for signal CLK
(pin A). Signal DIR (pin B) gives the direction of rotation. This mode permits the operation of external
binary counter modules (such as 74HC/HCT191, for
example), with signal NCLR (pin C) being used to reset the external counter. With a rising edge at CLK the
counter status is counted up or down, depending on
DIR
NCLR
Time [us]
Figure 18: DIR-INC mode
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Copying – even as an excerpt – is only permitted with iC-Haus approval in writing and precise reference to source.
iC-Haus does not warrant the accuracy, completeness or timeliness of the specification on this site and does not assume liability for any errors or omissions
in the materials. The data specified is intended solely for the purpose of product description. No representations or warranties, either express or implied, of
merchantability, fitness for a particular purpose or of any other nature are made hereunder with respect to information/specification or the products to which
information refers and no guarantee with respect to compliance to the intended use is given. In particular, this also applies to the stated possible applications or
areas of applications of the product.
iC-Haus conveys no patent, copyright, mask work right or other trade mark right to this product. iC-Haus assumes no liability for any patent and/or other trade
mark rights of a third party resulting from processing or handling of the product and/or any other use of the product.
As a general rule our developments, IPs, principle circuitry and range of Integrated Circuits are suitable and specifically designed for appropriate use in technical
applications, such as in devices, systems and any kind of technical equipment, in so far as they do not infringe existing patent rights. In principle the range of
use is limitless in a technical sense and refers to the products listed in the inventory of goods compiled for the 2008 and following export trade statistics issued
annually by the Bureau of Statistics in Wiesbaden, for example, or to any product in the product catalogue published for the 2007 and following exhibitions in
Hanover (Hannover-Messe).
We understand suitable application of our published designs to be state-of-the-art technology which can no longer be classed as inventive under the stipulations
of patent law. Our explicit application notes are to be treated only as mere examples of the many possible and extremely advantageous uses our products can
be put to.
iC-MA
ANGULAR HALL SENSOR / ENCODER
Rev B3, Page 18/18
ORDERING INFORMATION
Type
Package
Order Designation
iC-MA
DFN10 4 mm x 4 mm
Chip
iC-MA DFN10
iC-MA CHIP
iC-MA evaluation board
iC-MA EVAL MA1D
For technical support, information about prices and terms of delivery please contact:
iC-Haus GmbH
Am Kuemmerling 18
D-55294 Bodenheim
GERMANY
Tel.: +49 (61 35) 92 92-0
Fax: +49 (61 35) 92 92-192
Web: http://www.ichaus.com
E-Mail: [email protected]
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