US1881
Hall Latch – High Sensitivity
Features and Benefits
Wide operating voltage range from 3.5V to 24V
High magnetic sensitivity – Multi-purpose
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
Brushless DC motor commutation
Speed detection
Linear position detection
Angular position detection
Proximity detection
Ordering Information
Part No.
US1881
US1881
US1881
US1881
US1881
US1881
Temperature Code
E (-40° to 85°
C
C)
E (-40° to 85°
C
C)
K (-40° to 125°
C
C)
K (-40° to 125°
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)
SE (TSOT-3L)
UA (TO-92)
1 Functional Diagram
2 General Description
The Melexis US1881 is a Hall-effect latch
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 quite
suitable for use in automotive, industrial and
consumer 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.
3901001881
Rev 015
Page 1 of 12
Data Sheet
Jan/06
US1881
Hall Latch – High 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 Magnetic parameters vs. T
A
.....................................................................................................................6
11.2 Magnetic parameters vs. V
DD
...................................................................................................................6
11.3 V
DSon
vs. T
A
..............................................................................................................................................6
11.4 V
DSon
vs. V
DD
............................................................................................................................................6
11.5 I
DD
vs. T
A
..................................................................................................................................................6
11.6 I
DD
vs. V
DD
................................................................................................................................................6
11.7 I
OFF
vs. T
A
.................................................................................................................................................7
11.8 I
OFF
vs. V
DD
...............................................................................................................................................7
12 Test Conditions............................................................................................................. 7
12.1 Supply Current.........................................................................................................................................7
12.2 Output Saturation Voltage .......................................................................................................................7
12.3 Output Leakage Current ..........................................................................................................................7
12.4 Magnetic Thresholds ...............................................................................................................................7
13 Application Information................................................................................................ 8
13.1 Typical Three-Wire Application Circuit ....................................................................................................8
13.2 Two-Wire Circuit ......................................................................................................................................8
13.3 Automotive and Harsh, Noisy Environments Three-Wire Circuit ............................................................8
14 Application Comments ................................................................................................. 8
15 Standard information regarding manufacturability of Melexis products with
different soldering processes........................................................................................... 9
16 ESD Precautions ........................................................................................................... 9
17 Package Information................................................................................................... 10
17.1 SE Package (TSOT-3L).........................................................................................................................10
17.2 UA Package (TO-92 flat) .......................................................................................................................11
18 Disclaimer.................................................................................................................... 12
3901001881
Rev 015
Page 2 of 12
Data Sheet
Jan/06
US1881
Hall Latch – High Sensitivity
3 Glossary of Terms
MilliTesla (mT), Gauss
RoHS
TSOT
ESD
BLDC
Operating Point (B
OP
)
Release Point (B
RP
)
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
Magnetic flux density applied on the branded side of the package which turns
the output driver ON (V
OUT
= V
DSon
)
Magnetic flux density applied on the branded side of the package which turns
the output driver OFF (V
OUT
= high)
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 “K”
Temperature Suffix “L”
Symbol
T
A
T
A
T
A
Value
-40 to 85
-40 to 125
-40 to 150
Units
°C
°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
3901001881
Rev 015
Page 3 of 12
Data Sheet
Jan/06
US1881
Hall Latch – High Sensitivity
6 General Electrical Specifications
DC Operating Parameters T
A
= 25 C, V
DD
= 3.5V to 24V (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
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
Typ
Max
24
5
0.5
10
Units
V
mA
V
µA
µs
µs
KHz
°C/W
o
0.3
0.25
0.25
10
301
7 Magnetic Specifications
DC Operating Parameters V
DD
= 3.5V to 24V (unless otherwise specified)
Parameter
Symbol
Operating Point
B
OP
Release Point
B
RP
Hysteresis
B
HYST
Operating Point
B
OP
Release Point
B
RP
Hysteresis
B
HYST
Operating Point
B
OP
Release Point
B
RP
Hysteresis
B
HYST
Table 4: Magnetic specifications
Test Conditions
E spec., T
A
= 85°C
Min
0.5
-9.5
7
0.5
-9.5
7
0.5
-9.5
6
Typ
Max
9.5
-0.5
12
9.5
-0.5
12
9.5
-0.5
12.5
Units
mT
mT
mT
mT
mT
mT
mT
mT
mT
K spec., T
A
= 125°C
L spec., T
A
= 150°C
Note 1: For typical values, please refer to the performance graphs in section 11
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) OUT (SE) Test Conditions (UA)
South pole
B < B
RP
High
B > B
OP
North pole
B > B
OP
Low
B < B
RP
Table 5: Output behaviour versus magnetic pole
OUT (UA)
Low
High
o
o
South pole
North pole
North pole
OUT = high
South pole
OUT = low (V
DSon
)
UA package
OUT = high
OUT = low (V
DSon
)
SE package
3901001881
Rev 015
Page 4 of 12
Data Sheet
Jan/06
US1881
Hall Latch – High Sensitivity
9 Detailed General Description
Based on mixed signal CMOS technology, Melexis US1881 is a Hall-effect device with high magnetic
sensitivity. This multi-purpose latch suits most of the application requirements.
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, low current consumption and large choice of operating
temperature range according to “L”, “K” and “E” specification make this device suitable for automotive,
industrial and consumer 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 US1881 exhibits latch magnetic switching characteristics. Therefore, it requires both south and north
poles to operate properly.
SE package - Latch characteristic
UA package - Latch characteristic
The device behaves as a latch with symmetric operating and release switching points (B
OP
=|B
RP
|). This
means magnetic fields with equivalent strength and opposite direction drive the output high and low.
Removing the magnetic field (B→0) keeps the output in its previous state. This latching property defines the
device as a magnetic memory.
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.
3901001881
Rev 015
Page 5 of 12
Data Sheet
Jan/06
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