3425

3425 DUAL, CHOPPER-STABILIZED, ULTRA-SENSITIVE, BIPOLAR HALL-EFFECT SWITCH The A3425LK dual Hall-effect switch is an extremely temperature-stable and stress-resistant sensor especially suited for use in digital-encoder systems in the harsh environments of automotive or industrial applications over extended temperature ranges to +150°C. Superior high-temperature performance is made possible through dynamic offset cancellation, which reduces the residual offset voltage normally caused by device overmolding, temperature dependencies, and thermal stress. This device also eliminates the major manufacturing hurdles encountered in fine-pitch direction-detection applications, namely maintaining accurate mechanical location between the two active Hall elements. Here, the two Hall elements are photolithographically aligned to better than 1 µm, as contrasted with 100 µm or worse mechanical location tolerance when manufactured discretely. The A3425LK is an ultra-sensitive device optimized for use with highdensity ring magnets. The device includes on a single silicon chip a voltage regulator, two independent chopper-stabilized Hall-voltage generators , two smallsignal amplifiers, two Schmitt triggers, and two short-circuit protected open-collector outputs to sink up to 30 mA each. An on-board regulator permits operation with supply voltages of 3.3 to 26.5 volts. With suitable output pull ups, it can be used directly with bipolar or MOS logic circuits. The A3425LK dual Hall-effect switch ...