Improved detection performance from micropower Hall-effect switches

October 16, 2013 // By Graham Prophet
Diodes has extended its family of Hall effect switches with the introduction of a pair of high sensitivity, micropower devices, with greater design flexibility and savings in both power and space, in consumer, domestic, office and industrial products.

The AH1902 is an omnipolar device, detecting both north and south pole magnets. In default mode, the programmable AH1903 operates as a unipolar device, detecting a south pole at the part marked package surface. The device also offers an omnipolar mode, enabling it to meet the needs of multiple applications and to be changed ‘on the fly’ in the event of a field direction issue. The AH1903 function is changed via a simple select pin, driven by an external logic source or microcontroller.

The high sensitivity of both switches means weaker magnets can be employed or detection distances extended; the switches’ typical operating threshold switch point being ±35 Gauss.

Designed to be used with a low voltage supply, these switches will operate over the range 1.6V to 3.6V. This factor, coupled with an integral sleep function and a typical current consumption figure of 4.3 µA, suits them to battery-powered applications.

The switches are provided in a choice of space-saving low profile surface mount packages. The omnipolar AH1902 comes in the DFN1216-4, ultra-thin DFN2015-6 and SOT553 packages. In the 1.2 x 1.6 x 0.5mm DFN1216-4 package, the AH1903 is the smallest omnipolar/unipolar programmable Hall switch.

To accommodate a wide range of hand-held applications, the switches have an 8 kV electrostatic discharge withstand capability and offer good immunity to RF noise and other circuit stresses. Operating and release points are also highly stable over the temperature range -40ºC to +85ºC, and with a very low temperature coefficient, the switches are immune to early or late switching.

The AH1902 omnipolar Hall effect switch is priced at $0.18 and the AH1903 omnipolar/unipolar programmable Hall effect switch at $0.185 (10,000).

Diodes Inc.; www.diodes.com