MT6803 Magnetic Angle Sensor IC

www.magntek.de 1/ 10 Rev 1.0 10/2016

Features and Benefits

Based on advanced magnetic field

sensing technology

Measures magnetic field direction rather

than field intensity

Contactless angle measurement

Large air gap

Excellent accuracy, even for weak

magnetic field

Position tolerant

Negligible hysteresis

Single chip solution

RoHS Compliant 2011/65/EU

Applications

Contactless potentiometer

Steering angle sensor for EPS

Servo motor control

General Description

The MagnTek rotary position sensor MT6803 is an IC based on advanced magnetic field sensing

technology. The sensor contains two Wheatstone bridges formed by a magnet field sensing element

array. A rotating magnetic field in the x-y sensor plane delivers two sinusoidal output signals indicating

the angle (α) between the sensor and the magnetic field direction. Within a homogeneous field in the x-y

plane, the output signals are relatively independent of the physical placement in the z direction (air gap).

The sensor is only sensitive to the magnetic field direction as the sensing element output is specially

designed to be independent from the magnet field strength. This allows the device to be less sensitive to

magnet variations, stray magnetic fields, air gap changes and off-axis misalignment.

This contactless system measures the absolute angle of a diametrically magnetized on-axis magnet. It is

especially suitable for applications such as contactless potentiometer, EPS steering angle sensor, etc.

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Pin Configuration

Figure 1: Pin Configuration for SOP-8 Package

(Also showing sensor element center location, zero degree position and angle rotation direction)

Name Number Type Description

MODE 1 Digital input Set to logic low in normal operation; Set to logic

high in I2C mode.

NSP 2 Digital input External magnetic switch input for 360 detection

AOUT 3 Analog output Linear voltage output

VDD 4 Supply 5V supply

GND 5 Ground Ground

HVPP 6 Supply 7.5V supply only needed for NVM programming.

NC for normal operation.

SCL 7 Digital I/O I2C clock

SDA 8 Digital I/O I2C data

Family Members

※ MTT6803CT is qualified for automotive applications.

Part number Description

MT6803CT SOP-8 package, tubes packaging (3000pcs/bag)

MTT6803CT※ SOP-8 package, tubes packaging (3000pcs/bag)

MT6803 Magnetic Angle Sensor IC

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Functional Description

The MT6803 is manufactured in a CMOS standard process and uses advanced magnet sensing

technology to sense the magnetic field distribution across the surface of the chip. The integrated

magnetic sensing element array delivers a voltage representation of the magnetic field at the surface of

the IC.

A small low cost diametrically magnetized (two-pole) standard magnet can be used to provide angular

position information. The MT6803 senses the orientation of the magnetic field and generates linear

outputs as depicted in Figure 3. The output voltage amplitude is ratiometric to the supply voltage.

Figure 2: Simplified System Block Diagram

Figure 3: Typical Output Waveform (Magnet rotates in clock-wise direction)

0%

20%

40%

60%

80%

100%

0 30 60 90 120 150 180 210 240 270 300 330 360

Output Voltage (%VDD)

Angle (deg)

Figure 2 shows a simplified block diagram of the chip, consisting of the magnetic sensing element

realized by two interleaved Wheatstone bridges to generate cosine and sine signals, gain stages,

analog-to-digital converters (ADC) for signal conditioning, a digital signal processing (DSP) unit for angle

calculation and digital-to-analog convert (DAC) to generate linear voltage output. Other supporting

blocks such as LDO, NVM, I2C, etc. are also included.

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Absolute Maximum Ratings (Non-Operating)

Stresses beyond those listed under “Absolute Maximum Ratings “may cause permanent damage to the

device. These are stress ratings only. Functional operation of the device at these or any other conditions

beyond those indicated under “Operating Conditions” is not implied. Exposure to absolute maximum

rating conditions for extended periods may affect device reliability.

Parameter Notes Min Max Unit

DC voltage at pin VDD - -0.3 8 V

DC voltage at pin HVPP - -0.3 8 V

Storage temperature - -55 160 °C

Operating Temperature MT6803 -40 85 °C

MTT6803 -40 150 °C

Electrostatic discharge

(HBM)

MT6803 - ±2 kV

MTT6803 - ±4 kV

Electrical Characteristics

Operating conditions: Ta= -40 to +150°C, VDD= 3.0-5.5V unless otherwise noted.

Symbol Parameter Conditions/Notes Min Typ Max Unit

VDD Supply Voltage - 3.0 5 5.5 V

HVPP Supply Voltage - 7.25 7.5 7.75 V

Idd Supply Current - - 3.0 4.0 mA

Sens Sensitivity Programmable - 0.44 - %VDD/°

Vsathi Output Saturation

Voltage High Programmable - 90 - %VDD

Vsatlo Output Saturation

Voltage Low Programmable - 10 - %VDD

LSB Analog Output

Resolution 10-bit DAC - 0.078 - %VDD

INL Integral Non-Linearity Note (1) - ±1.0 ±2.0 Degrees

Anoi Output Noise

Ta=25°C, VDD=3.3V,

RMS value, excluding

DAC quantization noise

- 0.02 - %VDD

Erm Ratiometric Error Note (2) -0.3 - 0.3 %

TPwrUp Power-up time - - - 1.1 ms

Tdelay Propagation delay - - - 0.5 ms

Analog Output Characteristics

Rout Output Resistance - - - 10 Ω

RL Output Load

Pull-up or pull-down 1 - - kΩ

CL - - - 500 pF

I2C IO Characteristics

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VIH High level input voltage - VDD-1 - - V

VIL Low level input voltage - - - 0.8 V

VSON Open Drain Output

Saturation Voltage Iout = 3.3 mA - - 0.4 V

ILK Input Leakage Current - - - ±1 μA

I2C Timing Specification

Fscl SCL Clock - 100 400 kHz

tlow SCL Low Period - 1 - - μs

thigh SCL High Period - 1 - - μs

tsudat SDA Setup Time - 0.1 - - μs

thddat SDA Hold Time - 0 - 0.9 μs

thdsta Start Hold Time - 0.6 - - μs

tsusta Start Setup Time - 0.6 - - μs

tsusto Stop Setup Time - 0.6 - - μs

tbuf New Transmission

Time - 1.3 - - μs

Notes:

1. The typical error value can be achieved at room temperature and with no off-axis misalignment error.

The max error value can be achieved over operation temperature range, at maximum air gap and

with worst-case off-axis misalignment error.

2. The analog output is by design ratiometric, i.e. it is proportional to the supply voltage VDD. The

ratiometric error is calculated as follows.

Erm5V

5∙ 100%

Magnetic Input Specification

Operating conditions: Ta= -40 to +150°C, VDD= 3.3-5.5V unless otherwisenoted. Two-pole cylindrical

diametrically magnetized source.

Symbol Parameter Notes Min Typ Max Unit

Dmag Diameter

Recommended magnet:

Ø8mm x 2.5mm for

cylindrical magnets

- 8 - mm

Tmag Thickness - - 2.5 - mm

Bpk Magnetic input field

amplitude Measured at the IC surface. 300 - 3000 Gauss

AG Air Gap Magnet to IC surface

distance (Figure4). 1.0 - 3.0 mm

RS Rotation Speed - - - 10 KRPM

DISP Off-Axis

Misalignment

Misalignment error between

sensor center and magnet - - 0.3 mm

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axis (Figure4).

TCmag1 Recommended

magnet material

and

temperature drift

NdFeB (Neodymium Iron

Boron) - -0.12 -

%/°C

TCmag2 SmCo (Samarium Cobalt) - -0.035 -

Figure4: Magnet Arrangement

I2C Operation

Alternative to the linear voltage output, the MT6803 also provides an I2C interface for host IC to read back

angle information from its internal registers listed below. The slave address of the device is 0000110 in 7-bit

binary form. The read/write protocol is explained in details in this section.

Address Description

0x03 Angle_Readback<7:0>

0x04 Angle_Readback<15:8>

Figure 5: I2C Timing Diagram

Abbreviation

SACK Acknowledged by slave

MACK Acknowledged by master

NACK Not acknowledged by master

RW Read/Write

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Start/Stop/Ack

START: Data transmission begins with a high to transition on SDA while SCL is held high. Once I2C

transmission starts, the bus is considered busy.

STOP: STOP condition is a low to high transition on SDA line while SCL is held high.

ACK: Each byte of data transferred must be acknowledged. The transmitter must release the SDA line

during the acknowledge pulse while the receiver mush then pull the SDA line low so that it remains

stable low during the high period of the acknowledge clock cycle.

NACK: If the receiver doesn’t pull down the SDA line during the high period of the acknowledge clock

cycle, it’s recognized as NACK by the transmitter.

I2C Write I2C write sequence begins with start condition generated by master followed by 7 bits slave address and

a write bit (R/W=0). The slave sends an acknowledge bit (ACK=0) and releases the bus. The master

sends the one byte register address. The slave again acknowledges the transmission and waits for 8 bits

data which shall be written to the specified register address. After the slave acknowledges the data byte,

the master generates a stop signal and terminates the writing protocol.

STA

RT

Slave Address R

W

SA

CK

Register Address

(0x09)

SA

CK

Data

(0x01)

SA

CK

ST

OP

0 0 0 0 1 1 0 0 0 0 0 0 1 0 0 1 0 0 0 0 0 0 0 1

I2C Read

I2C write sequence consists of a one-byte I2C write phase followed by the I2C read phase. A start

condition must be generated between two phase. The I2C write phase addresses the slave and sends

the register address to be read. After slave acknowledges the transmission, the master generates again

a start condition and sends the slave address together with a read bit (R/W=1). Then master releases

the bus and waits for the data bytes to be read out from slave. After each data byte the master has to

generate an acknowledge bit (ACK = 0) to enable further data transfer. A NACK from the master stops

the data being transferred from the slave. The slave releases the bus so that the master can generate a

STOP condition and terminate the transmission.

The register address is automatically incremented and more than one byte can be sequentially read out.

Once a new data read transmission starts, the start address will be set to the register address specified

in the current I2C write command.

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STA

RT

Slave Address R

W

SA

CK

Register Address

(0x00)

SA

CK

0 0 0 0 1 1 0 0 0 0 0 0 0 0 0 0

STA

RT

Slave Address R

W

SA

CK

Data

(0x00)

MA

CK

Data

(0x01)

0 0 0 0 1 1 0 1 D D D D D D D D D D D D D D D D

MA

CK

Data

(0x02)

MA

CK

………………………

……….

MA

CK

Data

(0x07)

NA

CK

ST

OP

D D D D D D D D ………………………

……….

D D D D D D D D

Application Information

Reference Circuit Figure 6 shows a reference circuit for typical applications that use the analog output. For applications

that use I2C interface to obtain angle information, the reference circuit in Figure 7 is recommended. For

harsh working environment, it is recommended to add filtering (e.g. ferrite beads) and protection circuit

(e.g. TVS) to the supply.

Figure 6: Reference Application Circuit for Analog Interface

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Figure 7: Reference Application Circuit for I2C Interface

Magnet Selection and Placement

It is recommended that the magnetic field density at the chip surface reach 300 Gauss to guarantee that

the magnetic sensing elements operate in saturation mode to ensure good linearity. Please be noted that

the sensing element in the chip is not at the package center, rather it is aligned with PIN 3 and 6 edges

(see the figures in the “Package Information” section). It is required that the magnet’s center axis be

aligned with the sensing element center. Any misalignment introduces additional angle error. Magnets

with larger radius are more tolerant to off-axis misalignment. It also allows the magnet to be placed at the

large air gap distance from the chip. 360 Degree Detection

By default, MT6803 does not distinguish north and south pole, which makes its output have a period of

180 degrees. To enable 360 degree detection, it is possible to add external magnetic switch sensor

devices such as Hall or GMR sensor to help it distinguish north and south pole. For details, please refer

to application note AN001.

Programming

MT6803 can be programmed through dedicated programmer PB02 with its companion GUI software.

The following parameters can be programmed: start angle, stop angle, sensitivity, output saturation

(clamp) voltage, optional external magnetic switch sensor input, etc.

MT6803 Magnetic Angle Sensor IC

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PACKAGE DESIGNATOR

(MT6803CT) SOP-8

A

A1

A2

D

b

E1

E

e

c

L

ɗ

L1

L1'

Symbol Dimensions in Millimeters Dimensions in Inches

Min Max Min Max

A 1.595 1.775 0.063 0.070

A1 0.050 0.150 0.002 0.006

A2 1.350 1.550 0.053 0.061

b 0.375 0.425 0.015 0.017

c 0.170 0.250 0.007 0.010

D 4.700 5.100 0.185 0.200

E 3.875 3.925 0.153 0.155

E1 5.800 6.200 0.228 0.244

e 1.270(BSC) 0.050(BSC)

L 0.615 0.765 0.024 0.030

L1 1.040REF 0.041REF

L1-L1’ - 0.120 - 0.005

y 1.900 1.950 0.075 0.077

z 0.526 0.609 0.021 0.024

θ 0˚ 8˚ 0˚ 8˚

x 0.860 0.034