AS5040
10Bit 360° Programmable Magnetic Rotary Encoder
1 General Description
The AS5040 is a contactless magnetic rotary encoder
for accurate angular measurement over a full turn of
360°. It is a system-on-chip, combining integrated Hall
elements, analog front end and digital signal processing
in a single device.
To measure the angle, only a simple two-pole magnet,
rotating over the center of the chip, is required. The
magnet may be placed above or below the IC.
The absolute angle measurement provides instant
indication of the magnet’s angular position with a
resolution of 0.35° = 1024 positions per revolution. This
digital data is available as a serial bit stream and as a
PWM signal.
Furthermore, a user-programmable incremental output
is available, making the chip suitable for replacement of
various optical encoders.
An internal voltage regulator allows the AS5040 to
operate at either 3.3 V or 5 V supplies.
Figure 1: Typical Arrangement of AS5040 and Magnet
Data Sheet
2 Key Features
Contactless high resolution rotational position
encoding over a full turn of 360 degrees
Two digital 10bit absolute outputs:
- Serial interface and
- Pulse width modulated (PWM) output
Three incremental output modes:
- Quadrature A/B and Index output signal
- Step / Direction and Index output signal
- 3-phase commutation for brushless DC
motors
- 10, 9, 8 or 7 bit user programmable
resolution
User programmable zero / index position
Failure detection mode for magnet placement
monitoring and loss of power supply
Rotational speeds up to 30,000 rpm
Push button functionality detects movement
of magnet in Z-axis
Serial read-out of multiple interconnected
AS5040 devices using Daisy Chain mode
Wide temperature range: - 40°C to + 125°C
Fully automotive qualified to AEC-Q100,
grade 1
Small Pb-free package: SSOP 16 (5.3mm x
6.2mm)
3 Applications
Industrial applications:
- Contactless rotary position sensing
- Robotics
- Brushless DC motor commutation
- Power tools
Benefits
Complete system-on-chip
Flexible system solution provides absolute,
PWM and incremental outputs simultaneously
Ideal for applications in harsh environments
due to contactless position sensing
Tolerant to magnet misalignment and airgap
variations
No temperature compensation necessary
No calibration required
Automotive applications:
- Steering wheel position sensing
- Gas pedal position sensing
- Transmission gearbox encoder
- Headlight position control
- Power seat position indicator
Office equipment: printers, scanners, copiers
Replacement of optical encoders
Front panel rotary switches
Replacement of potentiometers
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