SS248
CMOS Omnipolar High Sensitivity Micropower Hall Switch
Features
Micropower consumption for battery powered applications
Omnipolar, output switches with absolute value of North or South pole from magnet
Operation down to 2.5V
High sensitivity for direct reed switch replacement applications
3 pin SOT23 (suffix SO)
3 pin SIP (suffix UA)
General Description
The S248 Omnipolar Hall effect sensor IC is fabricated from
mixed signal CMOS technology .It incorporates advanced
chopper-stabilization techniques to provide accurate and stable
magnetic switch points.
The circuit design provides an internally controlled clocking
mechanism to cycle power to the Hall element and analog
signal processing circuits. This serves to place the high
current-consuming portions of the circuit into a “Sleep” mode.
Periodically the device is “Awakened” by this internal logic
and the magnetic flux from the Hall element is evaluated
against the predefined thresholds. If the flux density is above
or below the Bop/Brp thresholds then the output transistor is
driven to change states accordingly. While in the “Sleep” cycle
the output transistor is latched in its previous state. The design
has been optimized for service in applications requiring
extended operating lifetime in battery powered systems.
The output transistor of the S248 will be latched on (Bop) in
the presence of a sufficiently strong South or North magnetic
field facing the marked side of the package. The output will be
latched off (Brp) in the absence of a magnetic field.
Applications
Solid state switch
Handheld Wireless Handset Awake Switch
Lid close sensor for battery powered devices
Magnet proximity sensor for reed switch replacement in low duty cycle applications
1
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May 1, 2012
SS248
CMOS Omnipolar High Sensitivity Micropower Hall Switch
Typical Application Circuit
SEC's pole-independent sensing technique allows for operation
with either a north pole or south pole magnet orientation,
enhancing the manufacturability of the device. The
state-of-the-art technology provides the same output polarity
for either pole face.
It is strongly recommended that an external bypass capacitor be
connected (in close proximity to the Hall sensor) between the
supply and ground of the device to reduce both external noise
and noise generated by the chopper-stabilization technique.
This is especially true due to the relatively high impedance of
battery supplies.
Functional Block Diagram
2
V2.00
May 1, 2012
SS248
CMOS Omnipolar High Sensitivity Micropower Hall Switch
Absolute Maximum Ratings
Parameter
Supply Voltage(operating)
Supply Current
Output Voltage
Output Curent
Operating Temperature Range
Storage Temperature Rang
ESD Sensitivity
Symbol
V
DD
I
DD
V
OUT
I
OUT
T
A
T
S
-
Value
6
5
6
5
-40 to 85
-50 to 150
4000
Units
V
mA
V
mA
C
C
V
Exceeding the absolute maximum ratings may cause permanent damage. Exposure to absolute-maximum rated conditions for
extended periods may affect device reliability.
DC Electrical Characteristics
DC Operating Parameters: T
A
= 25℃, V
DD
=2.75V.
Parameter
Operating voltage
Supply current
Output Current
Saturation Voltage
Awake mode time
Sleep mode time
Symbol
V
DD
I
DD
I
OUT
V
SAT
T
AW
T
SL
I
OUT
=1mA
Operating
Operating
175
70
Test Conditions
Operating
Average
Min
2.5
Typ
3
5
1.0
0.4
Max
5.5
Units
V
μA
mA
V
μS
mS
Magnetic Characteristics
Output Voltage(V)
3.0
2.5
2.0
1.5
1.0
0.5
0
-80
-60
-40
-20
0
20
40
60
80
ON
B
OPN
B
RPN
B
RPS
B
OPS
OFF
Magnetic Flux(Gauss)
4
V2.00
May 1, 2012
Power technology
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