Hall-effect switches

Hall-effect switches reduce power consumption

A pair of micro-power, omnipolar, Hall-Effect sensor switches from Diodes Inc feature the ability to detect the magnetic field generated by the North and South poles and so remove the need for production processes that manage magnet orientation in applications such as contact-less lid or display orientation, position detection tasks in notebooks, mobile phones, digital still cameras and camcorders. And being micro-power they significantly reduce power consumption in battery-powered hand-held devices.

The AH1802 has an open drain single output, with the ultra-high sensitivity required for sensing small or vertically oriented magnets. Housed in a compact, ultra-thin, 0.4mm high DFN2015 package, the AH1802 fits height-critical slider style phones. The device consumes only 24µW for a supply voltage of 3.0V and has an operational range of 2.5V to 5.5V.

The AH1888 has dual, complementary push-pull outputs, which enable the device to be directly connected to a system processor without the use of pull-up resistors. Outputs adjust to polarity changes, enabling the device to support the key, wheel-type magnets used to detect position and orientation for displays or keyboards that pivot or rotate. The AH1888 is offered in a low profile, 0.55/0.60mm high, SOT553 package. The device consumes only 15µW for a supply voltage of 1.8V and has an operational range of 1.65V to 3.0V.

The AH1802 and AH1888 operate within an operating temperature range of -40ºC to 85ºC.  In the presence of a local magnetic field, the sensor produces a low level “on” output signal. The sensors’ chopper stabilization circuitry delivers superior temperature stability, guarding against switch-point drift and rendering the new devices less sensitive to physical stress. Both devices support a broad variety of battery cell configurations, from single-cell lithium ion to dual-cell alkaline/zinc.