US5781
Unipolar Hall Switch – Medium Sensitivity
Features and Benefits
Wide operating voltage range from 3.5V to 24V
Medium sensitivity
CMOS technology
Chopper-stabilized amplifier stage
Low current consumption
Open drain output
Thin SOT23 3L and flat TO-92 3L
both RoHS Compliant packages
Application Examples
Automotive, Consumer and Industrial
Solid-state switch
Interrupter
Current detector
Proximity detection
Ordering Information
Part No.
US5781
US5781
US5781
US5781
Temperature Code
E (-40° to 85°
C
C)
E (-40° to 85°
C
C)
L (-40° to 150°C)
C
L (-40° to 150°C)
C
Package Code
SE (TSOT-3L)
UA (TO-92)
SE (TSOT-3L)
UA (TO-92)
1 Functional Diagram
2 General Description
The Melexis US5781 is a unipolar Hall-effect
switch designed in mixed signal CMOS
technology.
The device integrates a voltage regulator, Hall
sensor with dynamic offset cancellation system,
Schmitt trigger and an open-drain output driver, all
in a single package.
Thanks to its wide operating voltage range and
extended choice of temperature range, it is
suitable for use in automotive and solid state
switch applications.
The device is delivered in a Thin Small Outline
Transistor (TSOT) for surface mount process and
in a Plastic Single In Line (TO-92 flat) for through-
hole mount.
Both 3-lead packages are RoHS compliant.
3901005781
Rev 013
Page 1 of 11
Data Sheet
Nov/06
US5781
Unipolar Hall Switch – Medium Sensitivity
Table of Contents
1 Functional Diagram ........................................................................................................ 1
2 General Description........................................................................................................ 1
3 Glossary of Terms .......................................................................................................... 3
4 Absolute Maximum Ratings ........................................................................................... 3
5 Pin Definitions and Descriptions................................................................................... 3
6 General Electrical Specifications .................................................................................. 4
7 Magnetic Specifications ................................................................................................. 4
8 Output Behaviour versus Magnetic Pole ...................................................................... 4
9 Detailed General Description ......................................................................................... 5
10 Unique Features............................................................................................................ 5
11 Performance Graphs .................................................................................................... 6
11.1 Typical Magnetic Switch Points vs V
DD
....................................................................................................6
11.2 Magnetic Switch Points vs Temperature .................................................................................................6
11.3 Typical Saturation Voltage vsTemperature (V
DD
=12V;Iout=20mA) .........................................................6
12 Application Information................................................................................................ 7
12.1 Typical Three-Wire Application Circuit
....................................................................................................7
12.2 Two-Wire Circuit
......................................................................................................................................7
12.3 Automotive and Harsh, Noisy Environments Three-Wire Circuit
............................................................7
13 Application Comments ................................................................................................. 7
14 Standard information regarding manufacturability of Melexis products with
different soldering processes........................................................................................... 8
15 ESD Precautions ........................................................................................................... 8
16 Package Information..................................................................................................... 9
16.1 SE Package (TSOT-3L)...........................................................................................................................9
16.2 UA Package (TO-92 flat)
.......................................................................................................................10
17 Disclaimer.................................................................................................................... 11
3901005781
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Data Sheet
Nov/06
US5781
Unipolar Hall Switch – Medium Sensitivity
3 Glossary of Terms
MilliTesla (mT), Gauss
RoHS
TSOT
ESD
BLDC
Units of magnetic flux density:
1mT = 10 Gauss
Restriction of Hazardous Substances
Thin Small Outline Transistor (TSOT package) – also referred with the Melexis
package code “SE”
Electro-Static Discharge
Brush-Less Direct-Current
4 Absolute Maximum Ratings
Parameter
Symbol
Supply Voltage
V
DD
Supply Current
I
DD
Output Voltage
V
OUT
Output Current
I
OUT
Storage Temperature Range
T
S
Maximum Junction Temperature
T
J
Table 1: Absolute maximum ratings
Value
28
50
28
50
-50 to 150
165
Units
V
mA
V
mA
°C
°C
Exceeding the absolute maximum ratings may cause permanent damage. Exposure to absolute-maximum-
rated conditions for extended periods may affect device reliability.
Operating Temperature Range
Temperature Suffix “E”
Temperature Suffix “L”
Symbol
T
A
T
A
Value
-40 to 85
-40 to 150
Units
°C
°C
5 Pin Definitions and Descriptions
SE Pin
№
UA Pin
№
Name
1
1
VDD
2
3
OUT
3
2
GND
Table 2: Pin definitions and descriptions
Type
Supply
Output
Ground
Function
Supply Voltage pin
Open Drain Output pin
Ground pin
SE package
UA package
3901005781
Rev 013
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Data Sheet
Nov/06
US5781
Unipolar Hall Switch – Medium Sensitivity
6 General Electrical Specifications
DC Operating Parameters T
A
= 25 C, V
DD
= 12V (unless otherwise specified)
Parameter
Symbol
Supply Voltage
V
DD
Supply Current
I
DD
Output Saturation Voltage
V
DSon
Output Leakage Current
I
OFF
Output Rise Time
t
r
Output Fall Time
t
f
Maximum Switching Frequency
F
SW
SE Package Thermal Resistance
R
TH
UA Package Thermal Resistance
R
TH
Table 3: Electrical specifications
Test Conditions
Operating
B < B
RP
I
OUT
= 20mA, B > B
OP
B < B
RP,
V
OUT
= 24V
R
L
= 1kΩ, C
L
= 20pF
R
L
= 1kΩ, C
L
= 20pF
Single layer (1S) Jedec board
Min
3.5
0.5
Typ
2.5
0.3
0.01
0.25
0.25
10
301
200
Max
24
5
0.5
10
Units
V
mA
V
µA
µs
µs
KHz
°C/W
°C/W
o
7 Magnetic Specifications
DC Operating Parameters T
A
= 25 C, V
DD
= 12V (unless otherwise specified)
Parameter
Symbol
Operating Point
B
OP
Release Point
B
RP
Hysteresis
B
HYST
Table 4: Magnetic specifications
Test Conditions
Min
7
3.5
2
Typ
12
7.5
5
Max
15
10
7
Units
mT
mT
mT
o
8 Output Behaviour versus Magnetic Pole
DC Operating Parameters T
A
= -40 C to 150 C, V
DD
= 3.5V to 24V (unless otherwise specified)
Parameter
Test Conditions (SE)
South pole
B > B
OP
Null or weak magnetic field
B 0 or B < B
RP
North pole
B > B
OP
Table 5: Output behaviour versus magnetic pole
OUT (SE) OUT (UA)
High
Low
High
High
Low
High
o
o
North pole
South pole
OUT = low (V
DSon
)
UA package
OUT = low (V
DSon
)
SE package
3901005781
Rev 013
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Data Sheet
Nov/06
US5781
Unipolar Hall Switch – Medium Sensitivity
9 Detailed General Description
Based on mixed signal CMOS technology, Melexis US5781 is a Hall-effect device with medium magnetic
sensitivity. Its sensitivity enables high accuracy in position sensing by the use of small air gap.
The chopper-stabilized amplifier uses switched capacitor technique to suppress the offset generally observed
with Hall sensors and amplifiers. The CMOS technology makes this advanced technique possible and
contributes to smaller chip size and lower current consumption than bipolar technology. The small chip size is
also an important factor to minimize the effect of physical stress.
This combination results in more stable magnetic characteristics and enables faster and more precise design.
The wide operating voltage from 3.5V to 24V, “L” and “E” operating temperature range and low current
consumption make this device especially suitable for automotive and solid state switch applications.
The output signal is open-drain type. Such output allows simple connectivity with TTL or CMOS logic by using
a pull-up resistor tied between a pull-up voltage and the device output.
10 Unique Features
The US5781 exhibits unipolar magnetic switching characteristics. Therefore, it operates only with one
magnetic pole.
The UA package is south pole active:
Applying a south magnetic pole greater than B
OP
facing the
branded side of the package switches the output low.
The SE package is north pole active:
Applying a north magnetic pole greater than B
OP
facing the
branded side of the package switches the output low.
Removing the magnetic field (B→0) switches the output high.
The use of the opposite magnetic pole facing the branded side
does not affect the output state.
Unipolar switch characteristic
A magnetic hysteresis B
HYST
keeps B
OP
and B
RP
separated by a minimal value. This hysteresis prevents
output oscillation near the switching point.
3901005781
Rev 013
Page 5 of 11
Data Sheet
Nov/06
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