Integrated AMR Angle Sensor and

Signal Conditioner

Data Sheet

ADA4571

Product

Overview

Online

Documentation

Design

Resources

Discussion

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FEATURES

High precision 180° angle sensor

Maximum angular error of 0.5°

Analog sine and cosine outputs

Ratiometric output voltages

Low thermal and lifetime drift

SAR or Σ-Δ analog-to-digital converter (ADC) drive capable

Magnetoresistive (MR) bridge temperature compensation mode

Temperature range: −40°C to +150°C

EMI resistant

Fault diagnostics

Minimum phase delay

Qualified for automotive applications

Available in an 8-lead SOIC package

APPLICATIONS

Absolute position measurement (linear and angle)

Brushless dc motor control and positioning

Actuator control and positioning

Contactless angular measurement and detection

Magnetic angular position sensing

FUNCTIONAL BLOCK DIAGRAM

Figure 1.

GENERAL DESCRIPTION

The ADA4571 is an anisotropic magnetoresistive (AMR) sensor

with integrated signal conditioning amplifiers and ADC drivers.

The ADA4571 produces two analog outputs that indicate the

angular position of the surrounding magnetic field.

The ADA4571 consists of two die within one package, an AMR

sensor, and a fixed gain (G = 40 nominally) instrumentation

amplifier. The ADA4571 delivers clean and amplified cosine

and sine output signals related to the angle of a rotating

magnetic field. The output voltage range is ratiometric to the

supply voltage.

The sensor contains two Wheatstone bridges, at a relative angle

of 45° to one another. A rotating magnetic field in the x-y

sensor plane delivers two sinusoidal output signals with the

double frequency of the angle (α) between sensor and magnetic

field direction. Within a homogeneous field in the x-y plane,

the output signals are independent of the physical placement in

the z direction (air gap).

The ADA4571 is available in an 8-lead SOIC package.

COMPANION PRODUCTS

ADCs: AD7265, AD7266, AD7866, AD7902

Microconverter: ADuCM360

Current Sense Amplifier: AD8418A

Voltage Regulator Design Tool: ADIsimPower

Additional companion products on the ADA4571 product page

PRODUCT HIGHLIGHTS

1.

Contactless angular measurement.

2.

Measures magnetic field direction rather than field intensity.

3.

Minimum sensitivity to air gap variations.

4.

Large working distance.

5.

Excellent accuracy, even for weak saturation fields.

6.

Minimal thermal and lifetime drift.

7.

Negligible hysteresis.

8.

Single chip solution.

ADA4571

EMI

FILTER

EMI

FILTER

+

G = 40

+

–

–

G= 40

DRIVER

DRIVER

AMR BRIDGE

SENSORS

TEMPERATURE SENSOR

BRIDGE DRIVER

BIAS

OSCILLATOR

FAULT DETECTION

VTEMP

GC

VSIN

VCOS

PD

GND

GND

VDD