MLX90217
Hall-Effect Cam Sensor
Features and Benefits
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s
s
s
s
s
s
s
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
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Camshaft Sensor
Geartooth Sensor
Linear Encoder
Rotary Encoder
Direction Detection*
*See applications example
Ordering Information
Part No.
MLX90217
Temperature Suffix
L (-40
o
C to 150
o
C)
Package Code
UA (TO-92 flat)
Functional Diagram
Hall
Plate
10-Bit
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.
Jun/04
ADC
ADC
4-Bit
Amplifier
Logic
Voltage
Regulator
Protected
Output
1
Pin 1 - V
DD
(Supply)
Pin 2 - V
SS
(Ground)
Pin 3 - Output
Note:
Static
precautions.
3901090217
Rev. 009
sensitive
2
3
device,
please
observe
ESD
Page 1
MLX90217
Hall-Effect Cam Sensor
MLX90217 Electrical Specifications
Parameter
Supply Voltage
Supply Current
Supply Current
Leakage Current
Output Current
Output Saturation Voltage
Output Short Circuit Current
Output Short Circuit Shutdown
Clock Frequency
Output Rise Time
Output Fall Time
Bandwidth
Thermal Resistance
DC Operating Parameters T
A
= -40
o
C to 150
o
C, V
DD
= 3.5V to 24V (unless otherwise specified).
Symbol Test Conditions
V
DD
I
DD
I
DD
I
LEAK
I
OUT
V
SAT
I
FAULT
T
FAULT
f
CLK
t
r
t
f
BW
R
TH
Operating
V
DD
= 12V
V
DD
= 3.5V to 24V
V
OUT
= 3.5V to 24V
Operating
V
DD
= 12V, I
OUT
= 25mA
Fault
Fault
Operating
V
DD
=12V R
1
= 880W C
1
= 20pf
V
DD
=12V R
1
= 880W C
1
= 20pf
Operating
Operating
Min
3.5
1.5
1
-
-
-
50
100
300
Typ
-
3.0
-
-
-
-
100
-
500
-
-
Max
24
4.5
6
10
25
600
150
200
800
400
400
15
200
Units
V
mA
mA
µA
mA
mV
mA
µS
kHz
nS
nS
kHz
o
C/Watt
-
-
-
-
MLX90217 Magnetic Specifications
Parameter
Back Bias Range
Linear Region
Hysteresis
B
hys
DC Operating Parameters T
A
= -40
o
C to 150
o
C, V
DD
= 3.5V to 24V (Unless otherwise specified)
Symbol Test Conditions
B
BIAS
Operating
V
DD
= 12V
V
DD
= 3.5V to 24V
Min
-30
50
1.8
Typ
-
-
3.5
Max
400
500
10
Units
mT
mT
mT
Notes:
1mT=10Gauss
3901090217
Rev. 009
Page 2
Jun/04
j
MLX90217
Hall-Effect Cam Sensor
Performance Graphs
Absolute Maximum Ratings
Supply Voltage (Operating), V
DD
Supply Current (Fault), I
DD
Output Current (Fault), I
OUT
Output Current (Fault), I
fault
Output Voltage, V
OUT
Power Dissipation, P
D
Operating Temperature Range, T
A
Storage Temperature Range, T
S
Maximun Junction Temp, T
J
30V
50mA
30mA
50mA
30V
100mW
- 40°C to 150°C
- 65°C to 150°C
175°C
3901090217
Rev. 009
Page 3
Jun/04
MLX90217
Hall-Effect Cam Sensor
Application Notes
Maximum dynamic range is 500 mT. The
hysteresis is fixed at 5.0 mT. Best angular
accuracy will be obtained when the magnetic
circuit provides peak magnetic flux at the chip
near the high end of the linear range of 500 mT.
EMC protection using external components are
recommended. Two possibilities are shown on
the following page. Normally the South pole faces
the unbranded side of the device. A North pole
will enable a test sequence used in factory
testing.
Unique Features
The output is reset to the high state at power on
(output driver is off) whatever the field is. The
output only changes after the first min is detected.
The reset state holds no information about the
field. If the supply of the chip is raised slowly, the
reset state is not stable. This has been observed
at 0 field but it should be the same with small and
large fields.
Gear tooth sensors often need to be adjusted
after the module is assembled to align the
magnet with differential Hall plates or orient with
teeth. However the MLX90217 is “self adjusting”
over a wide range of back bias flux eliminating
the need for any trimming in the application. The
magnet may be glued to the back surface (non
branded side) of the IC using a cyanoacrylate
adhesive or suitable epoxy.
3901090217
Rev. 009
Page 4
Jun/04
j
MLX90217
Hall-Effect Cam Sensor
Applications Examples
3901090217
Rev. 009
Page 5
Jun/04
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