AS5043AB

AS5043 10-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER Adapter PCB Operation Manual AS5043 10 BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER ADAPTER PCB OPERATION MANUAL 1 The AS5043 adapter PCB: The AS5043 adapter PCB is a simple circuit allowing customers to test and evaluate the AS5043 rotary encoder rapidly without having to build their own test fixture or PCB. The PCB can be used as standalone unit or plugged onto the AS5043 demo board as external encoder. For Standalone operation, it can be supplied with 3.3V, 5V or 7,5...12V DC supply voltages. Figure 1: AS5043 Adapter PCB: top and bottom view Features: ƒ 100mil connector for direct connection to AS5043 demo board ƒ Provision for a 600mil DIP socket ƒ Hole in PCB to center a 6mm magnet at the bottom of the IC ƒ LED for MagRng output ƒ On-board 5V linear voltage regulator for 7,5…12V supplies ƒ 9V battery connector for standalone operation ƒ Dimensions: 35mm x 37mm (1.38 x 1.46 inch) Revision A.02, 04. Jul 06 www.austriamicrosystems.com Page 1 of 12 AS5043 10-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER Adapter PCB Operation Manual 2 General Description 4 Pin Description The AS5043 is a system-on-chip, combining integrated Hall elements, analog front end and digital signal processing in a single device. It provides incremental output signals and the absolute angular position of a magnet that is placed either above or below the device. The AS5043 can be configured to specific customer requirements by programming the integrated OTP (one time programmable) register. An internal voltage regulator allows the AS5043 to operate at either 3.3 V or 5 V supplies. Pin Symbol Type 1 MagRngn DO_OD Magnet Field Magnitude RaNGe warning; active low, indicates that the magnetic field strength is outside of the recommended limits. 2 Mode DI_PD, ST Mode input. Select between low noise (open, low) and high speed (high) mode. Internal pull-down resistor 3 CSn DI_PU, ST Chip Select, active low; Schmitt-Trigger input, internal pull-up resistor (~50kΩ) 4 CLK DI,ST Clock Input of Synchronous Serial Interface; Schmitt-Trigger input 5 NC - must be left unconnected 6 DO DO_T Data Output of Synchronous Serial Interface 7 VSS S Negative Supply Voltage (GND) 8 Prog_DI DI_PD OTP Programming Input and Data Input for Daisy Chain mode. Internal pull-down resistor (~74kΩ). Should be connected to VSS if not used 9 DACref AI DAC Reference voltage input for external reference 10 DACout AO DAC output (unbuffered, Ri ~8kΩ) 11 FB Feedback, OPAMP inverting input Must be left unconnected 12 Vout AI AO 13 NC - 14 NC - Must be left unconnected Figure 2: Typical arrangement AS5043 and magnet 3 Pin Configuration Description OPAMP output 15 VDD3V3 S 3V-Regulator Output for internal core, regulated from VDD5V.Connect to VDD5V for 3V supply voltage. Do not load externally. 16 VDD5V S Positive Supply Voltage, 3.0 to 5.5 V AS5043 Table 1: Pin description SSOP16 Figure 3: Pin configuration SSOP16 Revision A.02, 04. Jul 06 www.austriamicrosystems.com Page 2 of 12 AS5043 10-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER Adapter PCB Operation Manual 5 Principle of Operation 3.9 mm 3.9 mm 1 Circle of Hall elements on chip: 2.2mm diameter 2.433 mm Defined center 2.433 mm Area of allowed magnet misalignment: 0.5mm diameter The AS5043 chip consists of a ring of hall elements, placed at the center of the IC at a circle diameter of 2.2mm (86.6mil). The hall elements pick up the field of a magnet, placed atop this hall array circle. This information is digitized and fed into a digital signal processor (DSP), which calculates the angle of the magnet with a resolution of 0.0879 degrees or 4096 positions per revolution (10bit) at a sampling rate of 96µs (10kHz; Default) or 384µs (2.6kHz). The digital angle information is available in several formats: as serial 10-bit data stream, as pulse-width modulated (PWM) signal or as quadrature incremental signal Figure 4:Tolerances of magnet placement 5.1 Magnet considerations A magnet, having one north / one south pole in the horizontal axis is placed right above the ring of hall elements (see Figure 2). The magnet does not necessarily need to be circular, it can be rectangular as well, as long as the north and south pole are arranged horizontally over the center of the hall array ring. The magnetic field strength along this ring should be in the range of ±45….75 milliTesla (mT). 5.1.1 Magnet size The size of the magnet should be at least the size of the hall array ring (2.2mm). Smaller magnets are more critical in terms of misalignment due to the non-linear magnetic field distribution along the circumference of the magnet. The recommended magnet diameter is 4….6mm 5.1.2 Magnet distance and material To achieve the required field strength at a reasonable distance (~0.5…5mm), it is recommended to use rare-earth magnets, such as Samarium-Cobalt (SmCo) or Neodyne-Iron-Boron (NdFeB) magnets. 5.1.3 Magnet misalignment In theory, the magnet misalignment is not critical for this type of angular measurement. In practice however, magnets are not perfectly linear. The magnetic field strength does not increase linearly with the radius. As you get towards the boundary of the magnet, the magnetic field comes to a maximum and then weakens as you move further away from the center. Therefore, a magnet should be chosen, that is still in the linear range at a