AS5145B-HSST austriamicrosystems, AS5145B-HSST Datasheet - Page 30

• Manufacturer Part Number: AS5145B-HSST
• Description: IC ENCODER ROTARY 12-BIT 16-SSOP
• Manufacturer: austriamicrosystems
• Type: Linear, Rotary Encoder - Programmabler

Specifications of AS5145B-HSST

• Sensing Range: 45mT ~ 75mT
• Voltage - Supply: 3 V ~ 3.6 V, 4.5 V ~ 5.5 V
• Current - Supply: 21mA
• Current - Output (max): 4mA
• Output Type: Quadrature with Index (Incremental)
• Features: Programmable
• Operating Temperature: -40°C ~ 150°C
• Package / Case: 16-SSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

AS5145
Data Sheet - A p p l i c a t i o n I n f o r m a t i o n
9.7.5 Internal Timing Tolerance
The AS5145 does not require an external ceramic resonator or quartz. All internal clock timings for the AS5145 are generated by an on-chip RC
oscillator. This oscillator is factory trimmed to ±5% accuracy at room temperature (±10% over full temperature range). This tolerance influences
the ADC sampling rate and the pulse width of the PWM output:
9.7.6 Temperature
Magnetic Temperature Coefficient.
sensitive to temperature. While linear Hall sensors require a compensation of the magnet’s temperature coefficients, the AS5145 automatically
compensates for the varying magnetic field strength over temperature. The magnet’s temperature drift does not need to be considered, as the
AS5145 operates with magnetic field strengths from ±45…±75mT.
Example: A NdFeB magnet has a field strength of 75mT @ –40ºC and a temperature coefficient of -0.12% per Kelvin. The temperature change
is from -40º to +125º = 165K.The magnetic field change is: 165 x -0.12% = -19.8%, which corresponds to 75mT at -40ºC and 60mT at 125ºC.
The AS5145 can compensate for this temperature related field strength change automatically, no user adjustment is required.
9.7.7 Accuracy over Temperature
The influence of temperature in the absolute accuracy is very low. While the accuracy is less than or equal to ±0.5º at room temperature, it may
increase to less then or equal to ±0.9º due to increasing noise at high temperatures.
Timing Tolerance over Temperature.
to ±10%. Generally, the timing tolerance has no influence in the accuracy or resolution of the system, as it is used mainly for internal clock
generation.
The only concern to the user is the width of the PWM output pulse, which relates directly to the timing tolerance of the internal oscillator. This
influence however can be cancelled by measuring the complete PWM duty cycle instead of just the PWM pulse.
9.8 AS5145 Differences to AS5045
All parameters are according to AS5045 data sheet except for the parameters shown below:
Table 15. Difference Between AS5145 and AS5045
www.austriamicrosystems.com/AS5145
Ambient temperature range
- Absolute output; SSI interface: A new angular value is updated every 96µs (typ) in fast mode and every 384µs (typ) in slow mode.
- PWM output: A new angular value is updated every 384µs (typ). The PWM pulse timings T
internal oscillator. If only the PWM pulse width Ton is used to measure the angle, the resulting value also has this timing tolerance. How-
ever, this tolerance can be cancelled by measuring both Ton and T
ulation (PWM) Output on page 17)
Incremental encoder
Building Block
Pins 1 and 2
Data length
Resolution
Pin 6
MODE_Index pin, switch between fast and slow mode.
In case of incremental mode is this pin an output the
MagINCn, MagDECn: same feature as AS5045,
(12 bits zero position + 6 bits mode selection)
One of the major benefits of the AS5145 compared to linear Hall sensors is that it is much less
indicator red-yellow-green magnetic range
Pin3 (DTest1_A); Pin 4 (DTest2_B); Pin 6
The internal RC oscillator is factory trimmed to ±5%. Over temperature, this tolerance may increase
fast mode is setup in this case.
(12bits data + 6 bits status)
2x256 ppr low-jitter (10-bit)
2x1024 ppr (12-bit)
12bits, 0.088º/step
OTP write: 18 bits
Position =
-40ºC to +150ºC
(Mode_Index)
read: 18bits
AS5145
------------------------ - 1
(
t
t
on
Revision 1.11
on
⋅
+
4097
off
t
off
and calculating the angle from the duty cycle
)
–
MODE pin, switch between fast and slow mode
(12 bits zero position + 6 bits mode selection)
on
and T
(12bits data + 6 bits status)
off
MagINCn, MagDECn
also have the same tolerance as the
12bits, 0.088º/step
OTP write: 18 bits
-40ºC to +125ºC
Pin 3: not used
Pin 4: not used
read: 18bits
Not used
AS5045
(see Pulse Width Mod-
(EQ 7)
30 - 36