US1881
Features and Benefits
Chopper stabilized amplifier stage
Optimized for
brushless DC
motor applications
Miniature high reliability package
Operation down to 3.5V
CMOS for optimum stability, quality and cost
Low power consumption
Ordering Information
Part No.
US1881
US1881
US1881
Temperature Suffix
E (-40° to 85°
C
C)
K (-40° to 125°
C
C)
L (-40° to 150°
C
C)
Package Code
SO (SOT-23) or UA(TO-92)
SO (SOT-23) or UA(TO-92)
SO (SOT-23) or UA(TO-92)
Applications
Solid state switch
Brushless DC motor commutation
Speed Sensing
Linear position sensing
Angular position sensing
Current sensing
Pinout:
1 Functional Diagram
UA Package:
Pin1: VDD - supply
Pin2: GND - Ground
Pin3: OUT - Output
SO Package:
Pin1: VDD - supply
Pin2: OUT – Output
Pin3: GND - Ground
Note:
Static electricity sensitive device; please observe
ESD precautions. Reverse voltage protection is not in-
cluded. For reverse polarity protection, a 100Ohm resistor
in series with V
DD
is recommended.
2 Description
The US1881 is the industry’s first Hall integrated circuit in SOT-23 package. The US1881 is a bipolar Hall effect
sensor IC based on mixed signal CMOS technology. It incorporates advanced chopper stabilization techniques to
provide accurate and stable magnetic switch points. There are many applications for this HED in addition to those
listed above. The design, specifications and performance have been optimized for commutation applications in 5V
and 12V brushless DC motors.
In UA packaged device the output transistor will be latched on (Bop) in presence of a sufficiently strong South
pole magnetic field facing the marked side of the package. Similarly, the output will be latched off (Brp) in the
presence of a North field. The SOT-23 device behaviour is reverse to the UA device. The SOT-23 output transistor will
be latched on (B
OP
) in the presence of a sufficiently strong North pole magnetic field on the marked side
.
3901001881
Rev. 014
Page 1 of 12
Jun/05
US1881
Table of Contents
1
2
3
4
5
6
7
8
Functional Diagram....................................................................................................1
Description .................................................................................................................1
Glossary of Terms......................................................................................................3
Absolute Maximum Ratings ......................................................................................3
US1881 Electrical Characteristics ............................................................................3
Magnetic Characteristics...........................................................................................4
Unique Features .........................................................................................................4
Performance Graphs – unless otherwise specified Ta=25
o
C, VDD=12V...............5
8.1
8.2
8.3
8.4
8.5
8.6
Typical Magnetic Switch Points vs V
DD
........................................................................... 5
Magnetic Switch Points vs Temperature ......................................................................... 5
Output Voltage vs Magnetic Flux Density (Hysteresis).................................................... 5
Typical Saturation Voltage vs Temperature(V
DD
=12V;Iout=20mA)................................. 5
Typical Supply Current vs V
DD
........................................................................................ 6
Maximal Power Dissipation (MPD) Versus Temperature ................................................ 6
9
Application Information .............................................................................................7
9.1
9.2
9.3
Typical Three-Wire Application Circuit ............................................................................ 7
Two-Wire Circuit ............................................................................................................. 7
Automotive and Harsh, Noisy Environments Three-Wire Circuit ..................................... 7
10
11
12
13
14
Application Comments ..............................................................................................7
Pin Definitions and Descriptions ..............................................................................7
Reliability Information ...............................................................................................8
ESD Precautions ........................................................................................................8
Physical Characteristics............................................................................................9
UA Package Information ................................................................................................. 9
SOT23 Package Information......................................................................................... 10
14.1
14.2
15
Disclaimer .................................................................................................................11
3901001881
Rev. 014
Page 2 of 11
Jun/05
US1881
3 Glossary of Terms
MilliTesla (mT), Gauss:
Units of magnetic flux density; 1 milliTesla = 10 Gauss.
CMOS –
Complementary
Metal-Oxide Silicon -
A technology for building logic circuits that employs both “N”
and “P” channel MOS transistors. It allows one to make ICs with lots of transistors that consume small
amounts of power.
4 Absolute Maximum Ratings
Parameter
Supply Voltage (Operating)
Supply Current (Fault)
Output Voltage
Output Current (Fault)
Power Dissipation, UA/SO packages
Maximum Junction Temperature
Storage Temperature
Symbol
V
DD
I
DD
V
OUT
I
OUT
P
D
T
J
T
S
Value
24
50
24
50
700/389
165
-50 to 150
Units
V
mA
V
mA
mW
°
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”
Value
-40 to 85
-40 to 125
-40 to 150
Units
°
C
°
C
°
C
5 US1881 Electrical Characteristics
DC operating parameters: T
A
= 25 C, V
DD
= 12V (unless otherwise specified)
Parameter
Supply Voltage
Supply current
Saturation Voltage
Output Leakage
Output Rise Time
Output Fall Time
Maximum Switching
Frequency
Symbol
VDD
I
DD
V
DS(on)
I
OFF
t
r
t
f
fsw
Test Conditions
Operating
B < B
OP
I
OUT
= 20mA, B > B
op,
V
DD
=4.5÷18V
B < B
RP
, V
OUT
=24V
V
DD
= 12V, R
L
= 1k, C
L
= 20pF
V
DD
= 12V, R
L
= 1k, C
L
= 20pF
Operating
Min
3.5
1.1
Typ
2.0
0.4
0.01
0.04
0.18
10
Max
24
5.0
0.5
10
Units
V
mA
V
uA
us
us
KHz
o
3901001881
Rev. 014
Page 3 of 11
Jun/05
US1881
6 Magnetic Characteristics
Parameter
Operating Point
Release Point
Hysteresis
Operating Point
Release Point
Hysteresis
Operating Point
Release Point
Hysteresis
Operating Point
Release Point
Hysteresis
Symbol
B
OP
B
RP
B
HYS
B
OP
B
RP
B
HYS
B
OP
B
RP
B
HYS
B
OP
B
RP
B
HYS
Test Conditions
E/LUA, E/LSO,Ta=25 C,Vdd=3.5 … 24V DC
E/LUA, E/LSO,Ta=25 C,Vdd=3.5 … 24V DC
E/LUA, E/LSO,Ta=25 C,Vdd=3.5 … 24V DC
EUA, ESO, Ta=85 C,Vdd=3.5 … 24V DC
EUA, ESO, Ta=85 C,Vdd=3.5 … 24V DC
EUA, ESO, Ta=85 C,Vdd=3.5 … 24V DC
KUA, KSO, Ta=125 C,Vdd=3.5 … 24V DC
KUA, KSO, Ta=125 C,Vdd=3.5 … 24V DC
KUA, KSO, Ta=125 C,Vdd=3.5 … 24V DC
LUA, LSO, Ta=150 C,Vdd=3.5 … 24V DC
LUA, LSO, Ta=150 C,Vdd=3.5 … 24V DC
LUA, LSO, Ta=150 C,Vdd=3.5 … 24V DC
o
o
o
o
o
o
o
o
o
o
o
o
Min
1.0
-9.0
7.0
0.5
-9.5
7.0
0.5
-9.5
7.0
0.5
-9.5
6.0
Typ
5.0
-5.0
10.0
5.0
-5.0
10.0
5.0
-5.0
10.0
5.0
-5.0
10.0
Max
9.0
-1.0
12.0
9.5
-0.5
12.0
9.5
-0.5
12.0
9.5
-0.5
12.5
Units
mT
mT
mT
mT
mT
mT
mT
mT
mT
mT
mT
mT
Note:
1 mT = 10 Gauss
7 Unique Features
CMOS Hall IC Technology
The chopper stabilized amplifier uses switched capacitor techniques to eliminate the amplifier offset voltage,
which, in bipolar devices, is a major source of temperature sensitive drift. CMOS makes this advanced
technique possible. The CMOS chip is also much smaller than a bipolar chip, allowing very sophisticated
circuitry to be placed in less space. The small chip size also contributes to lower physical stress and less
power consumption.
3901001881
Rev. 014
Page 4 of 11
Jun/05
US1881
8 Performance Graphs –
unless otherwise specified Ta=25
o
C, VDD=12V
8.1
Typical Magnetic Switch Points vs V
DD
8.2
Magnetic Switch Points vs Temperature
8.3
Output Voltage vs Magnetic Flux Density
8.4
(Hysteresis)
Typical Saturation Voltage vs Tempera-
ture(V
DD
=12V;Iout=20mA)
3901001881
Rev. 014
Page 5 of 11
Jun/05
京公网安备 11010802033920号
EEWORLD
