AS5045-ASST austriamicrosystems, AS5045-ASST Datasheet - Page 26

• Manufacturer Part Number: AS5045-ASST
• Description: IC ENCODER PROG 12-BIT 16-SSOP
• Manufacturer: austriamicrosystems
• Type: Linear, Rotary Encoder - Programmabler

Specifications of AS5045-ASST

• 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: Digital, PWM, 12-Bit Serial
• Features: Programmable
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 16-SSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: AS5045-ASSTTR

AS5045
Data Sheet
The chip will continue to operate, but with degraded output linearity, if the signal field strength is outside the
recommended range. Too strong magnetic fields will introduce errors due to saturation effects in the internal
preamplifiers. Too weak magnetic fields will introduce errors due to noise becoming more dominant.
16 Failure Diagnostics
The AS5045 also offers several diagnostic and failure detection features:
16.1 Magnetic Field Strength Diagnosis
By software: the MagINC and MagDEC status bits will both be high when the magnetic field is out of range.
By hardware: Pins #1 (MagINCn) and #2 (MagDECn) are open-drain outputs and will both be turned on (= low with
external pull-up resistor) when the magnetic field is out of range. If only one of the outputs are low, the magnet is
either moving towards the chip (MagINCn) or away from the chip (MagDECn).
16.2 Power Supply Failure Detection
By software: If the power supply to the AS5045 is interrupted, the digital data read by the SSI will be all “0”s. Data is
only valid, when bit OCF is high, hence a data stream with all “0”s is invalid. To ensure adequate low levels in the
failure case, a pull-down resistor (~10kΩ) should be added between pin DO and VSS at the receiving side
By hardware: The MagINCn and MagDECn pins are open drain outputs and require external pull-up resistors. In
normal operation, these pins are high ohmic and the outputs are high (see Table 5). In a failure case, either when the
magnetic field is out of range of the power supply is missing, these outputs will become low. To ensure adequate low
levels in case of a broken power supply to the AS5045, the pull-up resistors (~10kΩ) from each pin must be
connected to the positive supply at pin 16 (VDD5V).
By hardware: PWM output: The PWM output is a constant stream of pulses with 1kHz repetition frequency. In case
of power loss, these pulses are missing
17 Angular Output Tolerances
17.1 Accuracy
Accuracy is defined as the error between measured angle and actual angle. It is influenced by several factors:
As a sum of all these errors, the accuracy with centered magnet = (Err
degrees @ 25°C (see Figure 22).
Misalignment of the magnet further reduces the accuracy. Figure 21 shows an example of a 3D-graph displaying
non-linearity over XY-misalignment. The center of the square XY-area corresponds to a centered magnet (see dot in
the center of the graph). The X- and Y- axis extends to a misalignment of ±1mm in both directions. The total
misalignment area of the graph covers a square of 2x2 mm (79x79mil) with a step size of 100µm.
For each misalignment step, the measurement as shown in is repeated and the accuracy (Err
0.25° in) is entered as the Z-axis in the 3D-graph.
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the non-linearity of the analog-digital converters,
internal gain and mismatch errors,
non-linearity due to misalignment of the magnet
Revision 1.7
max
– Err
min
)/2 is specified as better than ±0.5
max
– Err
min
)/2
26 – 33
(e.g.