Reduced power demand in Hall switches

August 23, 2013 // By Graham Prophet
Diodes Inc. has introduced six Hall effect sensor switches designed to save power in position and proximity detection roles in a variety of consumer, home appliance and industrial equipment. Optimised for a supply voltage range from 1.6V to 3.6V and using a hibernating clocking system to minimise power consumption, the switches’ average supply current is typically 4.3 µA at 1.8V.

The micropower Hall effect product introduction comprises the medium-sensitivity AH1895 and high-sensitivity AH1893, AH1897 and AH1812 omnipolar switches, the programmable high-sensitivity AH1894 omnipolar switch and the AH3360, a high-sensitivity unipolar (south pole) switch. These simple devices are in space-saving and low-profile X1-DFN1216-4 (1.2 x 1.6 x 0.5 mm) and leaded SOT553 (1.6 x 1.6 x 0.5 mm) packages.

All devices, with the exception of the AH1812, include an internal push-pull output structure, which enables a reduction in external component count and a simplification of PCB layouts. The AH1812 provides an open-drain output option for added flexibility in system pull-up.

A chopper-stabilised design means these highly integrated devices offer improved temperature stability, immunity to stress effects and minimal drift across their operating temperature range of -40ºC to +85ºC. Protection against ESD is also high at 8 kV, helping to improve product robustness and simplifying handling during manufacture.

The programmable-variant AH1894 enables users to select between one of two magnetic sensitivity ranges using a band select pin, allowing the one device to accommodate different strengths of magnets located at different distances from the Hall sensor. Band selection can either be hardwired or programmed electronically using an external logic source such as a microcontroller. Devices cost between $0.17 and $0.20 each (10,000).