General Description
Using low power CMOS process, the AS1918 is
designed for low power, high performance unipolar
detection hall-effect application, such as cover switch,
contactless switch, solid state switch and lid close
sensor etc battery operation. The hall IC integrated an
on-chip hall voltage generator for magnetic sensing, a
comparator that amplifiers the hall voltage, a Chopper
amplifier, a Schmitt trigger to provide switching
hysteresis for noise rejection, and a complementary
output.
The total power consumption of AS1918 is
typically less than 2.0uA at 3.3V power supply. AS1918
is designed to respond to alternating South pole. When
the magnetic flux density (B) is larger than operate
point (B
OPS
), the output will be turned on (low), the
output is held until the magnetic flux density (B) is
lower than release point (B
RPS
), then turn off (high).
The device is available in SIP-3L, SSOT23-3L,
SOT23-3L, DFN1216-4L, DFN1010-4L and SOT553
Packages and is rated over the -40°C to 85°C. The
package is RoHS compliant.

Features
 Input Voltage Range : 1.65V to 5.5V
 Micro-power consumption ideal for battery
power applications
 Unipolar Operation, easy to use as output
 Very high sensitivity hall sensor
 Low Power CMOS process technology
 Chopper stabilization amplifier stage
 Magnetic Sensitivity (typical)
B
OP
=±40Gauss, B
RP
=±25Gauss
 Good RF noise immunity
 No need pull-up resistor
 Small Solution Size
 RoHS & Green Compliant
 SIP-3L, SSOT23-3L, SOT23-3L, DFN1216-4L,
DFN1010-4L and SOT553 Packages
 -40℃ to +125 ℃ Temperature Range

Applications
 Cover switch in clam-shell cellular phones
 Cover switch in Notebook, PC/PAD
 Contact-less switch in consumer products
 Solid State Switch
 Handheld Wireless Handset Awake Switch
 Lid close sensor for battery-powered devise
 Magnet proximity sensor for reed switch
replacement in low duty cycle applications
 DV, DSC, and White Goods