as5145h austriamicrosystems, as5145h Datasheet - Page 15

• Manufacturer Part Number: as5145h
• Description: 12-bit Programmable Magnetic Rotary Encoder
• Manufacturer: austriamicrosystems

AS5145
Data Sheet - D e t a i l e d D e s c r i p t i o n
Incremental Power-up Lock Option.
status of the CSn pin:
Figure 6. Incremental Output
The hysteresis trimming is done at the final test (factory trimming) and set to 4 LSB, related to a 12 bit number.
Incremental Output Hysteresis.
of a rotational direction change, the incremental outputs have a hysteresis of 4 LSB. Regardless of the programmed incremental resolution, the
hysteresis of 4 LSB always corresponds to the highest resolution of 12 bit. In absolute terms, the hysteresis is set to 0.35 degrees for all
resolutions. For constant rotational directions, every magnet position change is indicated at the incremental outputs
if the magnet turns clockwise from position “x+3“ to “x+4“, the incremental output would also indicate this position accordingly. A change of the
magnet’s rotational direction back to position “x+3“ means that the incremental output still remains unchanged for the duration of 4 LSB, until
position “x+2“is reached. Following this direction, the incremental outputs will again be updated with every change of the magnet position.
Figure 7. Hysteresis Window for Incremental Outputs
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CSn = low at power-up: CSn has an internal pull-up resistor and must be externally pulled low (
the incremental outputs (A, B, Index) will be high until the internal offset compensation is finished. This unique state (A=B=Index = high)
may be used as an indicator for the external controller to shorten the waiting time at power-up. Instead of waiting for the specified maximum
power up-time (0), the controller can start requesting data from the AS5145 as soon as the state (A=B=Index = high) is cleared.
CSn = high or open at power-up: In this mode, the incremental outputs (A, B, Index) will remain at logic high state, until CSn goes low or a
low pulse is applied at CSn. This mode allows intentional disabling of the incremental outputs until, for example the system microcontroller
is ready to receive data.
D Test2_B
D Test1_A
Mode_Index
Incremental
Output
Indication
To avoid flickering incremental outputs at a stationary magnet position, a hysteresis is introduced. In case
X +6
X +5
X +4
X +3
X +2
X +1
X
ClockWise
After power-up, the incremental outputs can optionally be locked or unlocked, depending on the
X
Counterclockwise Direction
X +1
Clockwise Direction
X +2
X +3
Hysteresis :
0.35°
Revision 1.11
X +4 X +5
Programmed
Zero Position
3 LSB
1 LSB
X +6
Magnet Position
R ext 5kΩ
Counter ClockWise
≤
). If Csn is low at power-up,
(see Figure
7). For example,
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