The company has introduced a complete line of Hall Effect ICs for
portable electronics applications. An important feature of the product family
is its availability in the industry’s smallest chip-scale BGA package,
measuring just 1.1 mm square with a package height of just 0.5 mm. A slightly
larger surface-mount package, measuring 1.6 x 1.6 x 0.6 mm, is also available.
This mechanical advantage combined with the industry’s lowest average current
(as low as 3.5 µA), fully-integrated compensation and push-pull CMOS logic
output circuitry make these devices an attractive alternative to mechanical
switches and competitive Hall effect devices. The integrated dynamic offset
cancellation yields high sensitivity to allow for less precise placement of the
permanent magnet. The integrated CMOS output eliminates the need for external
pull-up resistors. In addition, the devices are rated at 8 kV ESD withstand,
important for reliable operation in handheld devices. Finally, the ROHM Hall
ICs are rated for -40C to +85C operation, again important for reliable
operation in portable consumer electronics. The ROHM Hall IC Switch family
includes Unipolar switches that can
be specified to switch on in the presence of either an S-Pole or N-pole
magnetic field of sufficient strength. The output will switch off if the
magnetic field is removed. It is commonly used in applications like jack-knife
or slide-open style cell phones to detect the open state. Power consumption is reduced through the implementation of intermittent
sensing with typical response time of 5 ms. Most competitive devices are
availalble in S-Pole-sensing. The Omnipolar switches, similar to Unipolar types but containing
two Hall plates, can be switched on with a either north or south field of
sufficient strength. The output will switch off when the field is removed. Used
in similar applications as Unipolar switches with the added benefit of removing
the requirement of placing the magnet polarity. Polarity Discriminating switches, similar to Omnipolar devices but
with separate outputs, are switched based upon detection of a north or south
pole. The outputs will switch off when the field is removed. It is used in
rotating screen devices to detect both open position and orientation. The line
also includes Bipolar switches that
switch on with a south magnetic field of sufficient strength and switch off
with a north magnetic field of sufficient strength. The output will not change
if the magnetic field is removed. It is used in jog wheel and track ball
applications to detect changes in menu selection. Extremely fast response time
(0.5 ms) and high sensitivity (Bop
/ Brp = 3.0 / -3.0 mT) is required for this application.
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