3901005781
Page 1
Aug/02
Rev. 008
Features and Benefits
Chopper stabilized amplifier stage
New miniature package / thin, high reliability package
Operation down to 3.5V
CMOS for optimum stability, quality, and cost
Applications
Solid state switch
Limit switch
Current limit
Interrupter
Ordering Information
Part No.
Temperature Suffix
Package Code
US5781
E ( -40C to 85C )
SO (SOT-23)
US5781
E ( -40C to 85C )
UA (TO-92 flat)
US5781
L ( -40C to 150C )
SO (SOT-23)
US5781
L ( -40C to 150C )
UA (TO-92 flat)
Description
The US5781 is a unipolar Hall effect sensor IC
fabricated from mixed signal CMOS technology. It
incorporates
advanced
chopper
stabilization
techniques to provide accurate and stable
magnetic
switch
points.
There
are
many
applications for this sensor in addition to those
listed above. The design, specifications and
performance have been optimized for applications
of solid state switches.
The output transistor will be switched on (B
OP
) in
the presence of a sufficiently strong South pole
magnetic field facing the marked side of the
package. Similarly, the output will be switched off
(B
RP
) in the presence of a weaker South field and
remain off with "0" field. The SOT-23 device is
magnetically reversed from the UA package. The
SOT-23 output transistor will be switched on (B
OP
)
in the presence of a sufficiently strong North pole
magnetic field subjected to the marked face.
Functional Diagram
Note: This is a static-sensitive device; please observe ESD
precautions. Reverse V
DD
protection is not included. For
reverse voltage protection, a 100W resistor in series with V
DD
is recommended.
Output
GND
V
DD
Voltage
Regulator
Chopper
SO Package
Pin 1 - V
DD
Pin 2 - Output
Pin 3 - GND
UA Package
Pin 1 - V
DD
Pin 2 - GND
Pin 3 - Output
3901005781
Page 2
Aug/02
Rev. 008
US5781 Electrical Specifications
DC operating parameters: T
A
= 25
o
C, V
DD
= 12V
DC
(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
5.0
mA
Saturation Voltage
V
DS(on)
I
OUT
= 20 mA, B>B
OP
0.3
0.5
V
Output Leakage
I
OFF
B<B
RP
, V
OUT
= 27V
0.01
10.0
A
Output Rise Time
t
r
V
DD
= 12V, R
L
= 1.1K
, C
L
= 20pf
0.04
s
Output Fall Time
t
f
V
DD
= 12V, R
L
= 1.1K
, C
L
= 20pf
0.18
s
US5781 Magnetic Specifications
Magnetic operating parameters: T
A
= 25
o
C, V
DD
=12 V
DC
(unless otherwise specified).
Parameter
Symbol
Test Conditions
Min
Typ
Max
Units
Operating Point
B
OP
7.0
12.0
15.0
mT
Release Point
B
RP
3.5
7.0
10.0
mT
Hysteresis
B
hys
2.0
5.0
7.0
mT
Note: 1 mT = 10 Gauss.
3901005781
Page 3
Aug/02
Rev. 008
Min/Max Magnetic Sw itch
Range Versus Tem perature
0
2
4
6
8
10
12
14
16
-40 -20
0
20 4 0
60 80 100 120 140
Tem perature C
F
l
u
x
D
e
n
s
i
t
y
m
V
/
m
T
5781
Performance Graphs
Typical Magnetic Switch Points
versus Temperature
5781
F
l
u
x
D
e
n
s
i
t
y
(
m
T
)
Temperature (C)
B
OP
B
RP
150
40
0
-40
80
120
12
6
0
3
9
B
H
y
S
14
B
OP Min
B
RP Max
B
RP Min
B
OP Max
3901005781
Page 4
Aug/02
Rev. 008
Performance Graphs
280
S
o
l
d
e
r
T
e
m
p
e
r
a
t
u
r
e
(
o
C
)
Time in Wave Solder (Seconds)
Wave Soldering Parameters
All Devices
15
200
220
240
260
10
5
0
20
25
30
500
0
P
a
c
k
a
g
e
P
o
w
e
r
D
i
s
s
i
p
a
t
i
o
n
(
m
W
)
Temperature (
o
C)
Power Dissipation
versus
Temperature
All Devices
80
100
200
300
400
0
-40
120
160
200
40
SO Package
R
JA
=575
o
C/W
UA Package
R
JA
=206
o
C/W
500
0
V
D
S
(
O
N
)
(
m
V
)
Temperature (
o
C)
Typical Saturation Voltage
versus
Temperature
V
DD
= 12 V, I
OUT
= 20mA
5781
80
100
200
300
400
0
-40
120
160
200
40
V
DS(ON)
5
0
S
u
p
p
l
y
C
u
r
r
e
n
t
(
m
A
)
Supply Voltage (V)
Typical Supply Current
versus
Supply Voltage
5781
15
1
2
3
4
10
5
0
20
25
30
T
A
= -40
o
C
T
A
= 25
o
C
T
A
= 125
o
C
3901005781
Page 5
Aug/02
Rev. 008
Two Wire Current Biasing Circuit
R
L
R
b
Hall
IC
Iout
I
D
D
V
DD
The resistors R
b
and R
L
can be used to bias the input
current, Iin. Refer to the part specification for limiting
values. This circuit will help in getting the precise ON
and OFF currents desired.
B
RP
= Ioff = (V
DD
/ Rb + I
DD
)
B
OP
= Ion = (Ioff + V
DD
/ R
L
)
I
IN
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.
Installation Comments
Consider temperature coefficients of Hall IC and
magnetics, as well as air gap life time variations.
Observe
temperature
limits
during
wave
soldering.
Applications
If reverse supply protection is desired, use a
resistor in series with the V
DD
pin. The resistor will
limit the supply current (Fault), I
DD
, to 50 mA. For
severe EMC conditions, use the application circuit
on this page.
Automotive and Severe
Environment Protection
Circuit
Hall IC
C1
4.7nF
C2
4.7nF
V
DD
V
SS
OUT
R
L
1.2K
Supply
Voltage
D1
R
1
100
Z1
Supply Voltage (Operating), V
DD
3.5V to 24V
Supply Current (Fault), I
DD
50mA
Output Voltage, V
OUT
3.5V to 24V
Output Current (Fault), I
OUT
50mA
Power Dissipation, P
D
100mW
Operating Temperature Range, T
A
-40 to 150C
Storage Temperature Range, T
S
-65 to 150C
Maximum Junction Temp, T
J
175C
ESD Sensitivity (All Pins)
+/- 2KV
Absolute Maximum Ratings
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