
Micropower Hall switches improve detection circuit performance
Bringing greater design flexibility and savings in both power and space, the AH1902 and AH1903 help raise the performance bar of a wide range of contact-less switch applications in consumer, domestic, office and industrial products.
The AH1902 is an omnipolar device, detecting both north and south magnetic fields. 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 using 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 is ±35G.
Designed to be used with a low voltage supply, these latest Hall switches from Diodes Incorporated operate over the 1.6 V to 3.6 V voltage range. This characteristic, coupled with an integral sleep function and a typical current consumption of 4.3 μA, makes them well-suited for battery-powered applications. To aid product miniaturization, the switches are provided in a variety of space- saving, low-profile, surface-mount packages. The omnipolar AH1902 comes in the DFN1216-4, the ultra-thin DFN2015-6 and SOT553 packages. The AH1903 is available in the 1.2×1.6×0.5 mm DFN1216-4 package, making it the industry’s smallest omnipolar/unipolar programmable Hall switch.
To accommodate a wide range of hand-held applications, the high-reliability 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 -40°C to +85°C temperature range, and with a low temperature coefficient, the switches are immune to early or late switching.
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