MMC2460MT-B - Memsic Inc. - Datasheet.Live

MEMSIC MMC246xMT Rev D Page 1 of 15 5/30/2014

±6 Gauss, Low Noise 2-axis

Magnetic Sensor

MMC246xMT

FEATURES

• Fully integrated 2-axis magnetic sensor and

electronic circuits requiring fewer external

components

• Superior Dynamic Range and Accuracy:

 ±6 G FSR with 16/14 bit operation

 0.25 mG per LSB resolution

 0.8 mG total RMS noise

 Enables heading accuracy <1º

• Wide operating Voltage ( 1.62 V ~ 3.6 V )

 Single 1.8 V supply capable

 1.8 V I/O compatibility.

• Low power consumption ( 50 µA @ 7Hz )

• 20 nA power down current function

• SET/RESET Function

 Allows for elimination of temperature

variation induced offset error (Null Field

output)

 Clears the sensors of residual

magnetization resulting from exposure

to strong external fields

• On-chip sensitivity temperature

compensation

• I

2

C Slave, FAST (≤400 KHz) mode

• Low Profile package 2 x 2 x 1 mm

• RoHS compliant

APPLICATIONS

Electronic Compassing

GPS Navigation Assist

Magnetic Field Measurement

DESCRIPTION

The MMC246xMT is a complete 2-axis magnetic sensor

with on-chip signal processing and integrated I

2

C bus.

The device can be connected directly to a

microprocessor, eliminating the need for A/D converters

or timing resources. It can measure magnetic fields

within the full scale range of ±6 G (gauss), with 0.25 mG

per LSB resolution in 16 bit operation mode and 0.8 mG

total RMS noise, enabling heading accuracies of <1° in

electronic compass applications.

Contact MEMSIC for access to advanced calibration

and tilt-compensation algorithms.

An integrated SET/RESET function provides for the

elimination of error due to Null Field output change with

temperature. In addition it clears the sensors of any

residual magnetic polarization resulting from exposure

to strong external magnets. The SET/RESET function

can be performed for each measurement or periodically

as the specific application requires.

The MMC246xMT is packaged in an ultra-small low

profile LGA package (2 x 2 x 1 mm) and operates over

a temperature range from -40 to 85 °C.

The MMC246xMT provides an I

2

C digital output with

400 KHz, fast mode operation.

Information furnished by MEMSIC is believed to be accurate and reliable.

However, no responsibility is assumed by MEMSIC for its use, or for any

infringements of patents or other rights of third parties which may result from

its use. No license is granted by implication or otherwise under any patent or

patent rights of MEMSIC.

MEMSIC, Inc.

One Technology Drive, Suite 325, Andover, MA01810, USA

Tel: +1 978 738 0900 Fax: +1 978 738 0196

www.memsic.com

MEMSIC MMC246xMT Rev D Page 2 of 15 5/30/2013

SPECIFICATIONS:

(Measurements at 25 °C, unless otherwise noted; V

DA

= V

DD

= 1.8 V unless otherwise specified)

Parameter

Conditions

Min

Typ

Max

Units

Field Range (each axis) Total applied field ±6 gauss

Supply Voltage V

DA

1.62

1

1.8 3.6 V

V

DD

(I

2

C interface) 1.62

1

1.8 3.6 V

Supply Voltage rising time 5.0 mS

Supply Current

2

(7measurements/second)

(Max = Mean +4σ at 25 C)

BW[1:0]=00, 16bit mode 50 60 µA

BW[1:0]=01, 16bit mode 25 30 µA

BW[1:0]=10, 14bit mode 20 25 µA

Power Down Current

3

20 50 nA

Operating Temperature -40 85 °C

Storage Temperature -55 125 °C

Linearity Error

(Least Squares Line) H

applied

±6 gauss

H

applied

±4 gauss 0.25

0.15 %FS

Hysteresis ±6 gauss 0.1 %FS

Repeatability Error ±6 gauss 0.25 %FS

Alignment Error

±

0.5

±

1.0 degrees

Transverse Sensitivity ±0.2 ±1.0 %

Total RMS Noise BW[1:0]=00, 16 bit mode 0.8 mG

BW[1:0]=01, 16 bit mode 1.0 mG

BW[1:0]=10, 14 bit mode 2.5 mG

Output resolution 16/14 bits

Heading accuracy

4

±0.5 ±1.0 degrees

Sensitivity

±6 gauss -3 +3 %

14 bit mode 1024 counts/G

16 bit mode 4096 counts/G

Initial sensitivity matching

( X to Y) ±1 %

Sensitivity Change over

Temperature -40 ~ 85 °C

±6 gauss -5 +5 %

Sensitivity Change over

Temperature Matching ( X to Y)

±1 %

Null Field Output ±6 gauss -0.2 +0.2 G

14 bit mode 8192 counts

16 bit mode 32768 counts

Null Field Output Change over

Temperature

5

Delta from 25°C

±120 mG

Null Field Accuracy over

temperature using SET/RESET

-40 to 85C ±2 mG

Disturbing Field 8 G

Maximum Exposed Field 10000 G

1

1.62 V is the minimum operation voltage. Both V

DA

and V

DD

should be equal to or greater than 1.62 V

2

Supply current is proportional to the number of measurements performed per second. See page 2 and 6 for

additional information.

3

See Supplemental Performance Characteristics for typical current change over temperature

4

Noise, resolution and accuracy specifications enable a typical heading accuracy calculation of 0.5 degrees. Actual

heading accuracy depends upon user system design and algorithms.

5

This error can be eliminated by using SET and RESET to determine the actual null field output at any temperature

from -40 to 85 °C

MEMSIC MMC246xMT Rev D Page 3 of 15 5/30/2013

SUPPLEMENTAL PERFORMANCE CHARACTERISITCS

(Vdd = 1.8 V)

MEMSIC MMC246xMT Rev D Page 4 of 15 5/30/2013

I

2

C INTERFACE I/O CHARACTERISTICS (VDD = 1.8 V)

Parameter

Symbol

Test Condition

Min.

Typ.

Max.

Unit

Logic Input Low Level V

IL

-0.5 0.3* V

DD

V

Logic Input High Level V

IH

0.7*V

DD

V

DD

V

Hysteresis of Schmitt input V

hys

0.2 V

Logic Output Low Level V

OL

0.4 V

Input Leakage Current I

i

0.1V

DD

<V

in

<0.9V

DD

-10 10 µA

SCL Clock Frequency f

SCL

0 400 kHz

START Hold Time t

HD;STA

0.6 µS

START Setup Time t

SU;STA

0.6 µS

LOW period of SCL t

LOW

1.3 µS

HIGH period of SCL t

HIGH

0.6 µS

Data Hold Time t

HD;DAT

0 0.9 µS

Data Setup Time t

SU;DAT

0.1 µS

Rise Time t

r

From V

IL

to

V

IH

0.3 µS

Fall Time t

f

From V

IH

to

V

IL

0.3 µS

Bus Free Time Between STOP and

START t

BUF

1.3 µS

STOP Setup Time t

SU;STO

0.6 µS

Timing Definition

ABSOLUTE MAXIMUM RATINGS*

Supply Voltage (V

DD

) ………………...-0.5 to +3.6 V

Storage Temperature ……….……-55 to +125 °C

Maximum Exposed Field ………………..10000 Gauss

*Stresses above those listed under Absolute Maximum Ratings may cause

permanent damage to the device. This is a stress rating only; the functional

operation of the device at these or any other conditions above those indicated

in the operational sections of this specification is not implied. Exposure to

absolute maximum rating conditions for extended periods may affect the

device’s reliability.

SDA

SCL

t

f

tr

t

LOW

t

HD;STA tHD;DAT

t

HIGH

tSU;DAT

t

SU;STA

tHD;STA

S

r

S

t

SU;STO

t

SP

S

P

tf

tr

t

BUF

MEMSIC MMC246xMT Rev D Page 5 of 15 5/30/2013

PIN DESCRIPTIONS: LGA Package

Pin Name Description I/O

1 VDA Power Supply P

2 Vpp Factory Use Only, Leave

Open NC

3 TEST Factory Use Only, Leave

Open/No Connection NC

4 C+ Short together I

5 C- I

6 CAP Connect to External Capacitor I

7

SCL

Serial Clock Line for I

2

C bus

I

8 VDD Power Supply for I

2

C bus P

9 SDA Serial Data Line for I

2

C bus I/O

10 VSA Connect to Ground P

All parts are shipped in tape and reel packaging with

9000 pieces per 13” reel or 3000 pieces per 7” reel.

Caution: ESD (electrostatic discharge) sensitive

device. HBM Class 1C; CDM Class C4

ORDERING GUIDE:

MMC246xMT

Note: I2C Address 0 is available in any quantity. Other

I2C addresses are available in minimum order

quantities of 3000.

MARKING ILLUSTRATION:

“Number” means the 1

st

two digits of the 1

st

line in

the marking. The 3

rd

digit

in the 1

st

line represents

Year Code (2 stands for

2012), the 2

nd

line

represents Lot Number.

Small circle indicates pin

one (1).

THEORY OF OPERATION

The Anisotropic Magneto-Resistive (AMR) sensors

are special resistors made of permalloy thin film

deposited on a silicon wafer. During manufacturing a

strong magnetic field is applied to the film to orient its

magnetic domains in the same direction, establishing

a magnetization vector. Subsequently, an external

magnetic field applied perpendicularly to the sides of

the film causes the magnetization to rotate and

change angle. This effect causes the film’s resistance

to vary with the intensity of the applied magnetic field.

The MEMSIC AMR sensor is incorporated into a

Wheatstone bridge configuration to maximize Signal

to Noise ratio. A change in magnetic field produces a

proportional change in differential voltage across the

Wheatstone bridge.

However, the influence of a strong magnetic field

(more than 16 Gauss) in any direction could upset, or

flip, the polarity of the film, thus changing the sensor

characteristics. A strong restoring magnetic field must

be applied momentarily to restore, or set, the sensor

characteristics. The MEMSIC magnetic sensor has an

on-chip magnetically coupled strap: a SET/RESET

strap pulsed with a high current, to provide the

restoring magnetic field

Number

2x Part number

20

MMC2460M

T

21 MMC2461MT

22 MMC2462MT

23 MMC2463MT

24 MMC2464MT

25

MMC246

5

M

T

26 MMC2466MT

27

MMC246

7

M

T

Address code: 0~7

Code 7bit I

2

C Address

0 0110000b

1 0110001b

2 0110010b

3 0110011b

4 0110100b

5 0110101b

6 0110110b

7 0110111b

Package type:

Code Type

T LGA10

RoHS compliant

Performance Grade:

Code Performance Grade

M Temp compensated

MEMSIC MMC246xMT Rev D Page 6 of 15 5/30/2013

PIN DESCRIPTIONS

V

DA

– This is the supply input for the circuits and the

magnetic sensor. The DC voltage must be between

1.62 and 3.6 V. A 1 uF by-pass capacitor is

recommended.

V

SA

– This is the ground pin for the magnetic sensor.

SDA – This pin is the I

2

C serial data line, and

operates in FAST (400 KHz) mode.

SCL – This pin is the I

2

C serial clock line, and

operates in FAST (400 KHz) mode.

V

DD

– This is the power supply input for the I

2

C bus,

and is 1.8 V compatible. DC voltage must be between

1.62 to 3.6 V. A 1 uF by-pass capacitor is

recommended.

TEST – Factory use only. No Connection.

CAP –Connect a 4.7 uF low ESR (typically smaller

than 0.2ohm) ceramic capacitor.

Vpp – Factory use only. No Connection

C+, C- –Short together on PCB for normal mode

operation.

EXTERNAL CIRCUITRY CONNECTION

(Top View)

HARDWARE DESIGN CONSIDERATION

 Provide adequate separation distance to devices

that contain permanent magnets or generate

magnetic fields (IE speakers, coils, inductors...)

The combined magnetic field to be measured and

interference magnetic field must be less than the

full scale range of the MMC2460xMT (±6 G).

 Provide adequate separation distance to current

carrying traces. Do not route current carrying

traces under the sensor or on the other side of the

PCB opposite the device.

 Do not cover the sensor with magnetized material

or material that may become magnetized, (IE,

shield box, LCD, battery, iron bearing material…).

 Do not place the device opposite magnetized

material or material that may become magnetized

located on the other side of the PCB.

Please refer to MEMSIC application note: AN-200-20-

0018 (MEMSIC Magnetic Sensor Hardware Design

Layout Guideline for Electronic Device).

POWER CONSUMPTION

The power consumed by the device is proportional to

the number of measurements taken per second. For

example, when in 16 bit mode The MEMSIC magnetic

sensor consumes 50µA (typical) at 1.8 V while making

7 measurements per second. If only 2 measurements

per second are performed, the current will be 50 * 2 /

7=14 µA.

The SET and RESET operations also contribute to

power consumption. Each time a SET or RESET is

executed the external 4.7uF capacitor delivers a

current pulse into an internal coil. This capacitor is

pre-charged to 3V using an internal dc-dc converter

from the VDA supply. Factoring in leakage and circuit

efficiency, a net charge of approximately 25uC is

required for each SET or RESET operation.

Therefore, as an example, if a SET and RESET

operation are initiated once every 10 seconds, the

average current would be 2 * 25 uC / 10 sec = 5 uA.

The peak current drawn from the VDA supply during

the pre-charge is approximately 1mA.

I

2

C INTERFACE DESCRIPTION

A slave mode I

2

C circuit has been implemented into

the MEMSIC magnetic sensor as a standard interface

for customer applications. The A/D converter and

MCU functionality have been added to the MEMSIC

sensor, thereby increasing ease-of-use, and lowering

power consumption, footprint and total solution cost.

The I

2

C (or Inter IC bus) is an industry standard bi-

directional two-wire interface bus. A master I

2

C

device can operate READ/WRITE controls to an

unlimited number of devices by device addressing.

The MEMSIC magnetic sensor operates only in a

slave mode, i.e. only responding to calls by a master

device.

1 uF

Power II

Power

1 uF

4.7uF

CAP C- C+

TEST

Vpp SCL

V

DD

SDA V

SA

V

DA

MEMSIC MMC246xMT Rev D Page 7 of 15 5/30/2013

I

2

C BUS CHARACTERISTICS

I

2

C Bus

The two wires in the I

2

C bus are called SDA (serial

data line) and SCL (serial clock line). In order for data

transfer to start, the bus has to be free, which is

defined by both wires in a HIGH output state. Due to

the open-drain/pull-up resistor structure and wired

Boolean “AND” operation, any device on the bus can

pull lines low and overwrite a HIGH signal. The data

on the SDA line has to be stable during the HIGH

period of the SCL line. In other words, valid data can

only change when the SCL line is LOW.

Note: Rp selection guide: 4.7 kOhm for a short I

2

C

bus length (less than 4 inches), and 10 kOhm for a

bus length less than 2 inches.

REGISTER MAP

Register Name

Address

Description

Xout Low 00H Xout LSB

Xout High 01H Xout MSB

Yout Low 02H Yout LSB

Yout High 03H Yout MSB

Status 06H Device status

Internal control 0 07H Control register 0

Internal control 1 08H Control register 1

Product ID 0 10H Product ID

R0 1BH Factor used register

R1 1CH Factory used register

R

2

1

D

H

Factory

used register

R3 1EH Factory used register

R

4

1

F

H

Factory used register

Product ID 1

20

H

Product ID

Register Details

Xout High, Xout Low

Xout

Low

7 6 5 4 3 2 1 0

Addr: 00H Xout[7:0]

Reset Value Xout[7:0]

Mode R

Xout

High

7 6 5 4 3 2 1 0

Addr: 01H Xout[15:8]

Reset Value Xout[15:8]

Mode R

X-axis output, unsigned format, the 2LSB of Xout Low will be fixed as “0” at 14bits mode.

Yout High, Yout Low

Y

out

Low

7 6 5 4 3 2 1 0

Addr: 02H Yout[7:0]

Reset Value Yout[7:0]

Mode R

Rp Rp

SDA

(Serial Data

Line)

SCL (Serial Clock

Line)

DEVICE 1

DEVICE 2

VDD

MEMSIC MMC246xMT Rev D Page 8 of 15 5/30/2013

Y

out

High

7 6 5 4 3 2 1 0

Addr: 03H Yout[15:8]

Reset Value Yout[15:8]

Mode R

Y-axis output, unsigned format, the 2LSB of Yout Low will be fixed as “0” at 14bits mode.

Status

Device Status

7 6 5 4 3 2 1 0

Addr: 06H Reserved ST_XY

_OK Rd_Done

Pump

On Meas

Done

Reset Value 5’h0 0 0 0

Mode R

Bit

Name

Description

Meas Done Indicates measurement event is completed. This bit should be checked before

reading the output

Pump On Indicates the charge pump status, after Refill Cap command, the charge pump will

start running, and this bit will stays high, it will be reset low after the cap reaches its

target voltage and the charge pump is shut off.

Rd_Done Indicates the chip was able to successfully read its memory.

ST_XY_OK Indicates self-test OK once this bit is “1”.

Internal Control 0

Control

Register 0 7 6 5 4 3 2 1 0

Addr: 07H Refill

Cap RESET SET No

Boost CM

Freq1 CM

Freq0 Cont

Mode

On

TM

Reset Value 0 0 0 0 0 0 0 0

Mode W W W W W W W W

Bit

Name

Description

TM Take measurement, set ‘1’ will initiate measurement.

Cont Mode On When set to a 1 this enables the Continuous Measurement Mode. The chip will

periodically take measurements of the magnetic field; the frequency of these

measurements is determined by bits CM Freq<1:0>.

CM Freq0 These bits determine how often the chip will take measurements in Continuous

Measurement Mode.

CM Freq1 CM Freq0 Frequency

0 0 1.5 Hz

0 1 12 Hz

1 0 25 Hz

1 1 50 Hz

CM Freq1

No Boost Setting this bit high will disable the charge pump and cause the storage capacitor to

be charged off VDD.

SET Writing “1” will set the sensor by passing a large current through Set/Reset Coil

RESET Writing “1” will reset the sensor by passing a large current through Set/Reset Coil at

a reversed direction

Refill Cap Writing “1” will recharge the capacitor at CAP pin, it is requested to be issued before

SET/RESET command.

MEMSIC MMC246xMT Rev D Page 9 of 15 5/30/2013

Internal Control 1

Control

Register 1 7 6 5 4 3 2 1 0

Addr: 08H

SW_RST

Temp_tst

ST_XY

Z

-

inhibit

Y

-

inhibit

X

-

inhibit

BW1

BW0

Reset Value

2’h0

0

Mode W W W W W W W W

Bit

Name

Description

BW0 Output resolution

BW1

BW0

Output Resolution

M

easurement Time

0

16bits

7.92mS

0 1 16bits 4.08mS

1

0

14bits

2.16mS

1

reserved

BW1

X-inhibit Factory-use Register

Y-inhibit

Z-inhibit Need to be set to “1”

ST_XY Self-test check, write “1” to this bit and execute a TM command, after TM is

completed the result can be read as bit ST_XY_OK. Write this bit to 0 to return to

normal operation

Temp_tst Factory-use Register

SW_RST Writing “1”will cause the part to reset, similar to power-up. It will clear all registers

and also re-read OTP as part of its startup routine.

R0, R1, R2, R3, R4

R0

7 6 5 4 3 2 1 0

Addr: 1BH Factory-use Register