MX868RTR Datasheet MX868R, MX868RTR | P1-P3

IXYS

MX868 1 03/03/08

Drawing No. 086809 www.claremicronix.com

MX868

12 Bit Digital Output Magnetic Flux Sensor

Features:

• Single 5 Volt Power Supply

• Externally Configurable ±50A Bi-Direction

Current Sense per Turn

• 12-Bit Serial Digital Output

• Full Scale Magnetic Flux Intensity of ±500

Gauss

• 2K Conversions/Second

• Microcontroller Compatible

• Standard 3 Wire Serial Interface plus Chip

Select

• In System Calibration: OTP Full Scale Trim via

the Serial I/O Port

• Programmable Digital Filter Time Constant

• 4mm x 4mm 8 Lead DFN package RoHS

Compliant

Applications:

• Load Detection and Management

• Motor Control

• Power Supplies

Ordering Information

Part No. Description

Qty

MX868R DFN-8 Tube 91

MX868RTR DFN-8 Tape & Reel 2500

General Description

The MX868 is a 12 Bit Digital Output Magnetic Flux

Sensor. The device is a complete sampled data

subsystem that converts a magnetic flux intensity of

±500 Gauss full scale into a 12-bit digital output

word. The sensor operates as a slave on the serial

interface with TTL-level compatible inputs SDI

(serial data input), SCK (serial clock), and CS* (chip

select, active low). Terminal SDO is the tri-state

serial data output.

An adjustable exponentially weighted moving

average digital filter is included that is capable of

improving the signal to noise ratio while reducing

the signal bandwidth. The full scale trim and/or the

digital filter time constant are controllable through

the serial I/O interface and are one-time

programmable through the serial interface (once

programmed, the values are loaded at every power-

on).

The MX868 can be mounted onto a PCB or

incorporated into a magnetic assembly and then

calibrated in-system through the serial interface.

The operating voltage range is 4.5V to 5.5V.

Functional Block Diagram Typical Application Circuit

Microcontroller

MX868

Power

Ground

PWR

CS*

SDI

SCK

GND

SDO

MISO

Select

MOSI

SCK

PWR

GND

Hall

Plate

I/O Reg

A/D

SDI

SCK

SDO

CS*

MX868

IXYS

Absolute Maximum Ratings T

= +25°C unless otherwise noted

Parameter Min Max Unit

Voltage (Any Pin to GND) +7 V

, DFN-8 Package 30 °C/W

Operating Temperature Range -40 +85 °C

Storage Temperature Range -65 150 °C

ESD Warning

ESD (electrostatic discharge) sensitive device. Although the MX868 features proprietary ESD protection circuitry,

permanent damage may occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD

precautions are recommended to avoid performance degradation or loss of functionality.

Electrical Characteristics

PWR= 5V, T = +25°C

Parameter Condition Min Typ Max Unit

Operating Voltage Range (PWR) 4.5 5.5 V

Supply Current (I

PWR

) 3 mA

Average A/D Reading Zero Magnetic Flux 2040 2048 2056 LSB

Average A/D Reading 100 Gauss, North Pole 2458 LSB

Output Noise Digital Filter Off 1.5

RMS

LSB

SCK pulse period 5 µS

SCK pulse width high or low 200 nS

CS* pulse period 500 µS

CS* falling to first SCK rising 100 nS

Last SCK falling to CS* rising 50 nS

SCK falling to SDO valid 60 nS

Digital output high PWR-0.5 V

Digital output low 0.5

Digital input low GND 0.8 V

Digital input high 2 PWR

Digital input current 1 µA

MX868 2 03/03/08

Drawing No. 086809 www.claremicronix.com

MX868

IXYS

Pin Description

Pin No. Name Description

1 PWR Input Voltage Supply

2 SDO Serial Data Output

3 NC No Connect

4 SCK Serial Clock Input

5 SDI Serial Data Input

6 NC No Connect

7 GND Connect to Ground

8 CS*

Active low chip select for the serial interface. When a logic “high” is on this pin, the

MX868 is tracking the hall input signal.

Detailed Circuit Description

The hall plate senses the magnetic field that is applied normal (perpendicular) to the package surface.

The signal from the hall plate is offset-corrected by detecting the difference between a pair of analog

samples during the acquisition time. During idle time (CS* high) the MX868 tracks the first analog

sample. Immediately (~10 nS) after the falling edge of CS* the first sample is held. The track mode for

the second sample starts nominally 32 µS after the falling edge of CS*. Typically 96 µS after the falling

edge of CS* the second sample is held and the resulting analog value is then converted by the A/D. The

result of the A/D conversion is loaded into the I/O register at the next falling edge of CS*, in preparation

for output on SDO.

The internal acquisition and A/D timing is asynchronous to the SCK serial interface clock. The magnetic

field sampling period is controlled externally by the time between consecutive CS* falling edges. For zero

magnetic field input the nominal A/D output is 2048 decimal. North pole towards the top surface of the

MX868 increases the A/D output count. Applications that require non-continuous one measurement at a

time operation should pulse CS* low twice, reading the data when CS* is low for the second time.

Serial Output (n)

A/D Convert (n+1)Acquisition (n+1)

A/D Convert (n)Acquisition (n)

CS*

SCK

SDO

externally controlled sampling period

13 12 11 10 987654321415 01 13 12 11 10 987654321415 01

MX868 3 03/03/08

Drawing No. 086809 www.claremicronix.com

P1-P3 P4-P6 P7-P9

MX868RTR

Mfr. #:

Buy MX868RTR

Manufacturer:

Description:

SENSOR HALL EFFECT SPI 8DFN

Lifecycle:

New from this manufacturer.

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MX868RTR

MX868RTR

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