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AS5055

Datasheet - Detailed Descr i p ti on

7 Detailed Description

User Programming.

The AS5055 does not require any programming by the user. A dedicated on-chip zero position programming is not implemented. If a zero

position programming is required, it is recommended to store the zero position offset in the host controller.

7.1 Operating Modes

Typical Application.

The AS5055 requires only a few external components in order to operate immediately when connected to the host microcontroller. Only 6 wires

are needed for a simple application using a single power supply: two wires for power and four wires for the SPI communication. A seventh

connection can be added in order to send an interrupt to the host CPU to inform that a new valid angle can be read. For additional information on

the layout and filtering of the SPI, please refer to Section 8.1.4 SPI Over Long Distances.

Figure 3. Typical Application Using SPI 4-Wire Mode and INT/ Output

Upon power-up, the AS5055 performs a full power-up sequence including one angle measurement. The completion of this cycle is indicated at

the INT/ output pin and the angle value is stored in an internal register. Once this output is low active, the AS5055 suspends to sleep mode.

7.1.1 Power Supply Filter

Due to the sequential internal sampling of the Hall sensors, fluctuations on the analog power supply (pin#12: VDD) may cause additional jitter of

the measured angle. This jitter can be avoided by providing a stable VDD supply.

The easiest way to achieve that is to add a RC filter: 15

Ω + 4.7µF in the power supply line as shown in Figure 3.

Alternatively, a filter: 33

Ω + 2.2µF may be used. However with this configuration, the minimum supply voltage is 3.15V.

µC

Interrupt

Supply: peripherals

4µ7

DC 3.0V ~ 3.6V

SPI

Interface

VDD

VDDp

VDD

VSS

INT/

Hall Sensors

AS5055

SS/

Wire

mode

EN_INT/

ADC

SPI Interface

Cordic

VDDp

VDDp

100n

Test_coil

15 ohm

Power Management