ADA4571BRZ Datasheet ADA4571BRZ-RL, ADA4571WHRZ-R7, ADA4571BRZ | P13-P15

ADA4571 Data Sheet

Figure 21. VTEMP Output Voltage vs. Temperature

Figure 22. Amplitude Synchronism (% k)

Figure 23. Output Voltage (V

SIN

and V

COS

) Peak-to-Peak vs.

Temperature (% V

)

Figure 24. Angular Error Delay vs. RPM (Mechanical)

100

–40 0 40 80 120

VTEMP (%V

)

TEMPERATURE (°C)

12514-028

–1.00 –0.75 –0.50 –0.25 0 0.25 0.50 0.75 1.00

COUNT (%)

AMPLITUDE MISMATCH (%)

12514-029

100

–40

0 40 80 120

OUT

(V p-p %V

)

TEMPERATURE (°C)

OUT

p-p GC OFF

OUT

p-p GC ON

12514-030

–1.0

–0.9

–0.8

–0.7

–0.6

–0.5

–0.4

–0.3

–0.2

–0.1

300 3000 30000

ANGULAR ERROR DELAY (Degrees)

RPM (Mechanical)

ERROR –40°C

ERROR +25°C

ERROR +150°C

12514-031

Rev. 0 | Page 12 of 21

Data Sheet ADA4571

TERMINOLOGY

Reference Position Error

The reference position error is the absolute mounting position

deviation of the sensor from its nominal placement. The

reference position for Y = 0 µm is the straight connection line of

Pin 2 and Pin 7. The X = 0 µm position is referred to the middle

distance of the package top. The position accuracies are within

a precision of ±0.05 mm (±50 µm) in both the X and Y

direction.

Reference Angle Error

The reference angle error is the absolute mounting rotation

deviation of the sensor from its nominal placement. Marking

the position for angle Φ= 0° position is referred parallel to the

straight connection line of Pin 2 and Pin 7.

Figure 25. Bonding Arrangement and Sensor Alignment in Package

Output Amplitude Synchronism Error

The output amplitude matching error (k) is defined as the

relationship between both output channel amplitudes at

continuously rotating magnetic excitation of the MR sensor

mathematically expressed as

k = 100% × V

SIN_P-P

COS_P-P

Uncorrected Angular Error

The uncorrected angular error is defined as the maximum

deviation from an ideal angle reading, when calculating the

angle from V

SIN

and V

COS

without offset calibration.

Single Point Calibration Angular Error

The single point calibration angular error is defined as the

maximum deviation from an ideal angle reading, when

calculating the angle from V

SIN

and V

COS

after an initial

calibration for offset voltage at T

= 25°C.

Dynamic Angular Error

The dynamic angular error is defined as the maximum

deviation from an ideal angle reading, when calculating the

angle from V

SIN

and V

COS

while a continuous offset calibration is

taken into account.

Phase Error

The phase error (Φ

ERR

) is defined as the rotation frequency

dependent error due to bandwidth limitation of the instrumen-

tation amplifiers. V

SIN

and V

COS

are impacted by the amplifier

propagation delay, referred to the actual angle direction of the

rotating magnetic field. The typical characteristics value can be

used for a first-order compensation of this error on very high

rotations per minute. For low rotational speed systems, this error

component is negligible and no compensation is necessary.

VCOS

GND

VSIN

VDD

GND

VTEMP

12514-006

Rev. 0 | Page 13 of 21

ADA4571 Data Sheet

THEORY OF OPERATION

The ADA4571 is an AMR sensor with integrated signal

conditioning amplifiers and ADC drivers. The

ADA4571

produces two analog outputs, sine and cosine, which indicate

the angular position of the surrounding magnetic field.

The AMR sensing element is designed and manufactured by

Sensitec GmbH.

Figure 27 shows the sine channel, consisting of an AMR sensor

element and the supporting functions for control, filtering,

buffering, and signal amplification. A reference voltage that is

proportional to the supply voltage is generated and it controls

the supply voltage of the sensor bridges. For noise and

electromagnetic compatibility (EMC) suppression purposes, the

bridge supply is low-pass filtered. The bridge output voltages

are amplified by a constant factor (G = 40, GC mode disabled)

and buffered. The single-ended outputs are biased around a

common-mode voltage of V

/2 and are capable of driving the

inputs of an external ADC referenced to the supply voltage.

For optimum use of the ADC input range, the cosine and sine

output voltages track the supply voltage ensuring a ratiometric

configuration. To achieve high signal performance both output

signals are carefully matched in both amplitude and phase. The

amplifier bandwidth is sufficient to ensure low phase delay at

maximum specified rotation speed.

Electromagnetic interference (EMI) filters at the sensor outputs

and between the first and second stages reject unwanted noise

and interference from appearing in the signal band.

The architecture of the instrumentation amplifier consists of

precision, low noise, zero drift amplifiers that feature a proprietary

chopping technique. This chopping technique offers a low input

offset voltage of 0.3 µV typical and an input offset voltage drift

of 0.02 µV/°C typical. The zero drift design also features

chopping ripple suppression circuitry, which removes glitches

and other artifacts caused by chopping.

Offset voltage errors caused by common-mode voltage swings

and power supply variations are also corrected by the chopping

technique, resulting in a dc common-mode rejection ratio that

is greater than 150 dB. The amplifiers feature low broadband

noise of 22 nV/√Hz and no 1/f noise component. These features

are ideal for amplification of the low level AMR bridge signals

for high precision sensing applications.

In addition, extensive diagnostics are integrated on-chip to self

check sensor and IC conditions.

Figure 26. Direction of Homogeneous Magnetic Field for α = 0°

Figure 27. Detailed Internal Diagram of the

ADA4571 Sine Channel

ADA4571

(Not to Scale)

TOP VIEW

12514-004

–

VDD

VDD/2

VDD

VTEMP

N



20pF

62.7pF

VSIN

AMR

BRIDGE

ADA4571

62.7pF

12514-005

Rev. 0 | Page 14 of 21

P1-P3 P4-P6 P7-P9 P10-P12 P13-P15 P16-P18 P19-P21 P22-P22

ADA4571BRZ

Mfr. #:

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Manufacturer:

Analog Devices Inc.

Description:

Board Mount Hall Effect / Magnetic Sensors AMR MAGNETIC SENS OR

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ADA4571BRZ

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