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AS5045B

Datasheet - Detailed Descr i p ti on

8 Detailed Description

The AS5045B is manufactured in a CMOS standard process and uses a spinning current Hall technology for sensing the magnetic field

distribution across the surface of the chip. The integrated Hall elements are placed around the center of the device and deliver a voltage

representation of the magnetic field at the surface of the IC.

Through Sigma-Delta Analog / Digital Conversion and Digital Signal-Processing (DSP) algorithms, the AS5045B provides accurate high-

resolution absolute angular position information. For this purpose a Coordinate Rotation Digital Computer (CORDIC) calculates the angle and

the magnitude of the Hall array signals.

The DSP is also used to provide digital information at the outputs MagINCn and MagDECn that indicate movements of the used magnet towards

or away from the device’s surface. A small low cost diametrically magnetized (two-pole) standard magnet provides the angular position

information (see Figure 16).

The AS5045B senses the orientation of the magnetic field and calculates a 12-bit binary code. This code can be accessed via a Synchronous

Serial Interface (SSI). In addition, an absolute angular representation is given by a Pulse Width Modulated signal at pin 12 (PWM). This PWM

signal output also allows the generation of a direct proportional analog voltage, by using an external Low-Pass-Filter. The AS5045B is tolerant to

magnet misalignment and magnetic stray fields due to differential measurement technique and Hall sensor conditioning circuitry.

Figure 4. Typical Arrangement of AS5045B and Magnet

8.1 Synchronous Serial Interface (SSI)

Figure 5. Synchronous Serial Interface with Absolute Angular Position Data

CSn

CLK

DO

Angular Position Data

Status Bits

1

D9

D8

D7

D6

D5

D4

D3

D2

D1

D0 OCF COF LIN

Mag

INC

Mag

DEC

Even

PAR

8

18

1

D11

D10

D11