US5681
Unipolar Hall Switch – High Sensitivity
3901005681 Page 1 of 11 Data Sheet
Rev 002 Mar/10
Features and Benefits
Wide operating voltage range from 3.5V to 24V
High sensitivity
CMOS technology
Chopper-stabilized amplifier stage
Low current consumption
Open drain output
Thin SOT23 3L RoHS Compliant package
Application Examples
Automotive, Consumer and Industrial
Solid-state switch
Interrupter
Current detector
Proximity detection
Ordering Information
Part No. Temperature Code Package Code
US5681 E (-40°C to 85°C) SE (TSOT-3L)
1 Functional Diagram
Voltage
Regulator
VDD
GND
OUT
DAMP
Hall
Plate
ESD protection ESD protection
Temperature
compensation
DIDO COMP
reference
Oscillator and
Bias
DIG
POR
2 General Description
The Melexis US5681 is a unipolar Hall-effect
switch designed in mixed signal CMOS
technology.
The device integrates a voltage regulator, Hall
sensor with advanced Correlated Double
Sampling (CDS) offset cancellation system and an
open-drain output driver, all in a single package.
Thanks to its wide operating voltage range and
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) 3-lead RoHS compliant
package.
US5681
Unipolar Hall Switch – High Sensitivity
3901005681 Page 2 of 11 Data Sheet
Rev 002 Mar/10
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
12 Test Conditions............................................................................................................. 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 SE Package Information (TSOT-3L)........................................................................... 10
18 Disclaimer.................................................................................................................... 11
US5681
Unipolar Hall Switch – High Sensitivity
3901005681 Page 3 of 11 Data Sheet
Rev 002 Mar/10
3 Glossary of Terms
MilliTesla (mT), Gauss Units of magnetic flux density:
1mT = 10 Gauss
RoHS Restriction of Hazardous Substances
TSOT Thin Small Outline Transistor (TSOT package) – also referred with the Melexis
package code “SE”
ESD Electro-Static Discharge
4 Absolute Maximum Ratings
Parameter Symbol Value Units
Supply Voltage
V
DD
2
8
V
Supply Current I
DD
50 mA
Output Voltage V
OUT
28 V
Output Current I
OUT
50 mA
Operating Temperature Range T
A
-40 to 85
°
C
Storage Temperature Range T
S
-50 to 150
°
C
Maximum Junction Temperature T
J
165
°
C
Table 1: Absolute maximum ratings
Exceeding the absolute maximum ratings may cause permanent damage. Exposure to absolute-maximum-
rated conditions for extended periods may affect device reliability.
5 Pin Definitions and Descriptions
Pin № Name Type Function
1 VDD Supply Supply Voltage pin
2 OUT Output Open Drain Output pin
3 GND Ground Ground pin
Table 2: Pin definitions and descriptions
US5681
Unipolar Hall Switch – High Sensitivity
3901005681 Page 4 of 11 Data Sheet
Rev 002 Mar/10
6 General Electrical Specifications
DC Operating Parameters T
A
= 25
o
C, V
DD
= 12V (unless otherwise specified)
Parameter Symbol Test Conditions Min Typ Max Units
Supply Voltage V
DD
Operating 3.5 24 V
Supply Current I
DD
B < B
RP
0.5 2.5 5 mA
Output Saturation Voltage V
DSon
I
OUT
= 20mA, B > B
OP
0.3 0.5 V
Output Leakage Current I
OFF
B < B
RP,
V
OUT
= 24V 0.01 10 µA
Output Rise Time t
r
R
L
= 1kΩ, C
L
= 20pF 0.25 µs
Output Fall Time t
f
R
L
= 1kΩ, C
L
= 20pF 0.25 µs
Output Update Frequency F
OUT
25 KHz
Power-On Time
1
t
ON
100 µs
Package Thermal Resistance R
TH
Single layer (1S) Jedec board 301 °C/W
Table 3: Electrical specifications
1
The Power-On Time represents the time from reaching the power-on reset level to the first refresh of the
output (first valid output state).Value according simulation only, not subject to production test.
7 Magnetic Specifications
DC Operating Parameters T
A
= 25
o
C, V
DD
= 12V (unless otherwise specified)
Parameter Symbol Test Conditions Min Typ Max Units
Operating Point B
OP
3.8 5.5 7.2 mT
Release Point B
RP
2 3.5 5 mT
Hysteresis B
HYST
1.5 2 2.7 mT
Table 4: Magnetic specifications
8 Output Behaviour versus Magnetic Pole
DC Operating Parameters T
A
= -40
o
C to 85
o
C, V
DD
= 3.5V to 24V (unless otherwise specified)
Parameter Test Conditions OUT
South pole B > B
OP
Low
Null or weak magnetic field B 0 or B < B
RP
High
North pole B > B
OP
High
Table 5: Output behaviour versus magnetic pole
OUT = low (V
DSon
)
US5681
Unipolar Hall Switch – High Sensitivity
3901005681 Page 5 of 11 Data Sheet
Rev 002 Mar/10
9 Detailed General Description
Based on mixed signal CMOS technology, Melexis US5681 is a Hall-effect device with high magnetic
sensitivity. Its sensitivity enables high accuracy in position sensing by the use of small air gap.
The Correlated Double Sampling (CDS) technique suppresses 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 accurate and stable magnetic characteristics, and enables faster and more
precise design.
The wide operating voltage from 3.5V to 24V and low current consumption make this device especially
suitable for 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 US5681 exhibits unipolar magnetic switching characteristics. Therefore, it operates only with one
magnetic pole.
OUT switches to Low
OUT switches to High
Unipolar switch characteristic
The US5681 device is south pole active:
Applying a south 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.
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.
US5681
Unipolar Hall Switch – High Sensitivity
3901005681 Page 6 of 11 Data Sheet
Rev 002 Mar/10
11 Performance Graphs
11.1 Magnetic parameters vs. T
A
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
5.5
6
6.5
7
7.5
-40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90
T
A
(
o
C)
Magnetic Field (mT)
Bop, Vdd=3.5V Bop, Vdd=24V
Brp, Vdd=24V Brp, Vdd=3.5V
Bhys, Vdd=24V Bhys, Vdd=3.5V
11.2 Magnetic parameters vs. V
DD
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
5.5
6
3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
VDD (Volts)
Magnetic Field(mT)
Bop, Ta=25oC Bop, Ta=85oC
Brp, Ta=25oC Brp, Ta=85oC
Bhys, Ta=25oC Bhys, Ta=85oC
11.3 V
DSon
vs. T
A
0
0.05
0.1
0.15
0.2
0.25
0.3
-40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90
Ta (
o
C)
VDSon (Volts)
VDD=3.5V
VDD=12V
VDD=24V
11.4 V
DSon
vs. V
DD
0
0.05
0.1
0.15
0.2
0.25
0.3
3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
VDD (Volts)
VDSon (Volts)
Ta=-40oC
Ta=25oC
Ta=85oC
11.5 I
DD
vs. T
A
0
0.5
1
1.5
2
2.5
3
3.5
4
-40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90
Ta (
o
C)
IDD (mA)
VDD=3.5V
VDD=12V
VDD=24V
11.6 I
DD
vs. V
DD
0
0.5
1
1.5
2
2.5
3
3.5
4
3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
VDD (Volts)
IDD (mA)
Ta=-40oC
Ta=25oC
Ta=85oC
US5681
Unipolar Hall Switch – High Sensitivity
3901005681 Page 7 of 11 Data Sheet
Rev 002 Mar/10
11.7 I
OFF
vs. T
A
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
0.2
-40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90
Ta (
o
C)
Ioff (µA)
VDD=3.5V
VDD=12V
VDD=24V
11.8 I
OFF
vs. V
DD
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
0.2
3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
VDD (Volts)
Ioff (µA)
Ta=-40oC
Ta=25oC
Ta=85oC
12 Test Conditions
Note : DUT = Device Under Test
12.1 Supply Current
12.2 Output Saturation Voltage
12.3 Output Leakage Current
12.4 Magnetic Thresholds
US5681
Unipolar Hall Switch – High Sensitivity
3901005681 Page 8 of 11 Data Sheet
Rev 002 Mar/10
13 Application Information
14 Application Comments
For proper operation, a 100nF bypass capacitor should be placed as close as possible to the device between
the V
DD
and ground pin.
For reverse voltage protection, it is recommended to connect a resistor or a diode in series with the V
DD
pin.
When using a resistor, three points are important:
- the resistor has to limit the reverse current to 50mA maximum (V
CC
/ R1 ≤ 50mA)
- the resulting device supply voltage V
DD
has to be higher than V
DD
min (V
DD
= V
CC
– R1.I
DD
)
- the resistor has to withstand the power dissipated in reverse voltage condition (P
D
= V
CC
2
/ R1)
When using a diode, a reverse current cannot flow and the voltage drop is almost constant (≈0.7V).
Therefore, a 100Ω/0.25W resistor for 5V application and a diode for higher supply voltage are recommended.
Both solutions provide the required reverse voltage protection.
When a weak power supply is used or when the device is intended to be used in noisy environment, it is
recommended that figure 13.3 from the Application Information section is used.
The low-pass filter formed by R1 and C1 and the zener diode Z1 bypass the disturbances or voltage spikes
occurring on the device supply voltage V
DD
. The diode D1 provides additional reverse voltage protection.
13.1 Typical Three-Wire Application Circuit
13.3 Automotive and Harsh, Noisy Environments
Three-Wire Circuit
13.2 Two-Wire Circuit
Note:
With this circuit, precise ON and OFF
currents can be detected using only
two connecting wires.
The resistors RL and Rb can be used
to bias the input current. Refer to the
part specifications for limiting values.
B
RP
: I
OFF
= I
R
+ I
DD
= V
DD
/R
b
+ I
DD
B
OP
: I
ON
= I
OFF
+ I
OUT
= I
OFF
+ V
DD
/R
L
US5681
Unipolar Hall Switch – High Sensitivity
3901005681 Page 9 of 11 Data Sheet
Rev 002 Mar/10
15 Standard information regarding manufacturability of Melexis
products with different soldering processes
Our products are classified and qualified regarding soldering technology, solderability and moisture sensitivity
level according to following test methods:
Reflow Soldering SMD’s (Surface Mount Devices)
• IPC/JEDEC J-STD-020
Moisture/Reflow Sensitivity Classification for Nonhermetic Solid State Surface Mount Devices
(classification reflow profiles according to table 5-2)
• EIA/JEDEC JESD22-A113
Preconditioning of Nonhermetic Surface Mount Devices Prior to Reliability Testing
(reflow profiles according to table 2)
Wave Soldering SMD’s (Surface Mount Devices) and THD’s (Through Hole Devices)
• EN60749-20
Resistance of plastic- encapsulated SMD’s to combined effect of moisture and soldering heat
• EIA/JEDEC JESD22-B106 and EN60749-15
Resistance to soldering temperature for through-hole mounted devices
Iron Soldering THD’s (Through Hole Devices)
• EN60749-15
Resistance to soldering temperature for through-hole mounted devices
Solderability SMD’s (Surface Mount Devices) and THD’s (Through Hole Devices)
• EIA/JEDEC JESD22-B102 and EN60749-21
Solderability
For all soldering technologies deviating from above mentioned standard conditions (regarding peak
temperature, temperature gradient, temperature profile etc) additional classification and qualification tests
have to be agreed upon with Melexis.
The application of Wave Soldering for SMD’s is allowed only after consulting Melexis regarding assurance of
adhesive strength between device and board.
Melexis is contributing to global environmental conservation by promoting lead free solutions. For more
information on qualifications of RoHS compliant products (RoHS = European directive on the Restriction Of
the use of certain Hazardous Substances) please visit the quality page on our website:
http://www.melexis.com/quality.asp
16 ESD Precautions
Electronic semiconductor products are sensitive to Electro Static Discharge (ESD).
Always observe Electro Static Discharge control procedures whenever handling semiconductor products.
US5681
Unipolar Hall Switch – High Sensitivity
3901005681 Page 10 of 11 Data Sheet
Rev 002 Mar/10
17 SE Package Information (TSOT-3L)
US5681
Unipolar Hall Switch – High Sensitivity
3901005681 Page 11 of 11 Data Sheet
Rev 002 Mar/10
18 Disclaimer
Devices sold by Melexis are covered by the warranty and patent indemnification provisions appearing in its
Term of Sale. Melexis makes no warranty, express, statutory, implied, or by description regarding the
information set forth herein or regarding the freedom of the described devices from patent infringement.
Melexis reserves the right to change specifications and prices at any time and without notice. Therefore, prior
to designing this product into a system, it is necessary to check with Melexis for current information. This
product is intended for use in normal commercial applications. Applications requiring extended temperature
range, unusual environmental requirements, or high reliability applications, such as military, medical life-
support or life-sustaining equipment are specifically not recommended without additional processing by
Melexis for each application.
The information furnished by Melexis is believed to be correct and accurate. However, Melexis shall not be
liable to recipient or any third party for any damages, including but not limited to personal injury, property
damage, loss of profits, loss of use, interrupt of business or indirect, special incidental or consequential
damages, of any kind, in connection with or arising out of the furnishing, performance or use of the technical
data herein. No obligation or liability to recipient or any third party shall arise or flow out of Melexis’ rendering
of technical or other services.
© 2005 Melexis NV. All rights reserved.
For the latest version of this document, go to our website at
www.melexis.com
Or for additional information contact Melexis Direct:
Europe, Africa, Asia: America:
Phone: +32 1367 0495 Phone: +1 603 223 2362
E-mail: sales_europe@melexis.com E-mail: sales_usa@melexis.com
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