3901090217 Page 1 Jun/04
Rev. 009
MLX90217
Hall-Effect Cam Sensor
Description
The MLX90217 is a self adjusting digital output
rotary position gear tooth sensor designed for use
in automotive camshaft sensing as well as other
speed sensing applications. It is designed to be
used with a bias magnet south facing the back
(non-marked) side of the IC. The device has an
open collector output which is short circuit
protected.
The MLX90217 is a sophisticated IC featuring an
on-chip 10-bit A/D Converter and logic that acts
as a digital sample and hold circuit. A separate 4-
bit A/D converter provides a fixed hysteresis. The
90217 does not have a chopper delay. The 90217
uses a single Hall plate which is immune to rotary
alignment problems. The bias magnet can be
from 50 to 400mT.
As the signal is sampled, the logic recognizes an
increasing or decreasing flux density. The output
will turn on (BOP) after the flux has reached its
peak and decreased by an amount equal to the
hysteresis. Similarly the output will turn off (BOP)
after the flux has reached its minimum value and
increased by an amount equal to the hysteresis.
Functional Diagram
Pin 1 - V
DD
(Supply)
Pin 2 - V
SS
(Ground)
Pin 3 - Output
Amplifier
Voltage
Regulator
ADC
ADC
Logic
Protected
Output
1 2 3
Hall
Plate
10-Bit
4-Bit
Features and Benefits
■
Rotary Position Gear Tooth Sensor
■
Short Circuit Protection
■
On-chip 10 bit A/D Converter
■
Self-Adjusting Magnetic Range
■
High Speed Operation
■
No Chopper Delay
■
Zero Speed Detection
■
No Rotary Orientation Concerns
Applications
■
Camshaft Sensor
■
Geartooth Sensor
■
Linear Encoder
■
Rotary Encoder
■
Direction Detection*
*See applications example
Ordering Information
Part No. Temperature Suffix Package Code
MLX90217 L (-40
o
C to 150
o
C) UA (TO-92 flat)
Note: Static sensitive device, please observe ESD
precautions.
