IC-MA3 Datasheet, PDF (15/19 Pages) IC-Haus GmbH – ANGULAR HALL SENSOR

iC-MA3 ANGULAR HALL SENSOR
WITH SIN/COS OUTPUT, CASCADABLE
SPEED SETTING (Integration Time)
Rev A2, Page 15/19
iC-MA3 has been designed to precisely measure high
rotary frequencies and fast changes of the rotary angle.
To cater for applications where the rotary frequency is
always significantly lower than the IC’s performance,
the bandwidth can be limited by pin FSEL. This en-
larges the integration time and improves the accuracy
of the measured signals.
In any case, the measurement signals are filtered to
suppress noise and disturbances, and the signal path
can be considered as a 1st order low-pass filter with a
cut-off frequency (fc). Due to this, a time lag (tlag) does
exist between the applied input angle (by the magnet
field) and the measured rotary angle (the output signal).
The table below reflects the principal dependencies.
A speed setting (selected by pin FSEL) can be freely
combined with any power saving mode (selected by
pin PSEL). Refer to the forementioned Example (Page
14) explaining the impact on the permissible maximum
rotary frequency.
Note that the low-pass characteristic also reduces the
amplitude of the measured Hall signals, what has to
be compensated by the amplitude control. Thus, the
measureable magnetic field strength Hext is valid for a
signal frequency fin < 0.1 · fc.
Full Power
Reduced Power
Eco Power
Full Speed
10 kHz
16 µs
1.7 kHz
90 µs
550 Hz
290 µs
Half Speed
5 kHz
32 µs
850 Hz
180 µs
275 Hz
580 µs
Min Speed
500 Hz
320 µs
85 Hz
1800 µs
30 Hz
5800 µs
Table 10: Typical values for cut-off frequency and time lag (at fin < 0.1 · fc)
SENSOR MONITORING
Monitoring by output GAIN
The analog signal at output GAIN represents the actual
amplification of the Hall signals, which is required to
reach the selected output level for the ports P0. . . P3.
Thus, it is a measure of the magnetic field strength seen
by the Hall sensors.
Depending on the output pin, the gain signal has differ-
ent voltage ranges:
At pin GAIN, the voltage range is:
V(GAIN) = 0 . . . Vout(GAIN)fs
(refer to Elec. Char. No. 202).
A lower magnetic field strength requires a higher am-
plification, so that it causes a higher signal level at
output GAIN. When the signal level at GAIN saturates,
the maximum amplification has been reached and the
outputs may not show the preset level anymore.
The gain signal is always present at pin GAIN. The gain
signal is also output to pin P2 or P3, if single-ended
output is selected by mode control inputs M0 and M1.
The voltage is zero at minimum gain (max. field
strength), and reaches Vout(GAIN)fs at maximum gain
(min. field strength).
At pins P2 and P3, the voltage range is:
V(P2, P3) = Vref . . . Vref + Vout()pk
(refer to Elec. Char. No. 501 and 502).
Here, Vout()pk is the signal amplitude according to the
output level preset by pin ASEL. The output voltage is
equal to Vref at minimum gain (max. field strength), and
reaches Vref + Vout()pk at maximum gain (min. field
strength).