Diodes Incorporated AH1892 programmable omnipolar Hall effect switch

The AH1892 is a programmable omnipolar Hall effect switch. It is designed for proximity and position detection in space-constrained portable and battery-powered products, including tablets, smartphones and camcorders. Provided in the miniature 4-pin 0.7 x 0.7 x 0.5 mm U-WLB0707-4 package, the micropower AH1892 is 17 times smaller than the common 3-pin TSOT packaged alternatives.

The package’s space-saving advantage is further enhanced by the switch’s integrated pull-up resistors, which simplify the external circuit layout and save more PCB space. A simple band select pin enables device sensitivity to be programmed to one of two predefined magnetic sensitivity ranges, allowing the device to be used in multiple applications with different field strengths. Sensitivity can also be adjusted on the fly via an external logic source such as a microcontroller, whereby band can be adjusted with a simple firmware upgrade.

The product’s lower operating voltage supply range, from 1.6 through to 3.6 V, has been specifically optimised for portable and battery-powered applications; with normal operation consuming an average current of just 4.3 µA, the switch ensures battery life is maximised. To help improve product reliability during manufacture and use, the device provides protection against electrostatic discharge to a level of 8 kV on supply and output pins.

With the Hall switch operating and release points highly stable over the extended temperature range from -40 to 85°C and with a low temperature coefficient, the AH1892 is immune to the possibility of early or late switching effects. The device’s chopper-based design also offers high resistance to RF noise and other circuit stresses.

Besides the miniature U-WLB0707-4 package, the product is also offered in the standard low-profile SOT553 package. A high-sensitivity version of the AH1892 will be made available later in the year (the AH1894), available in both SOT553 and DFN1216-4 package options.