A3425

he A3425 is a dual-output channel, bipolar switch with two separate Hall-effect  sensor circuits, each providing a separate digital output for speed and direction  signal processing capability. Each sensor circuit has its own independent Hall  element, which are photolithographically aligned to better than 1 µm. Maintaining  accurate mechanical location between the two active Hall elements eliminates the  major manufacturing hurdle encountered in fi  ne-pitch detection applications. The  A3425 is a highly sensitive, temperature-stable magnetic sensing device, which  is ideal for use in ring magnet-based speed and direction systems used in harsh  automotive and industrial environments.

The A3425 monolithic integrated circuit contains two independent Hall effect  switches, located approximately 1 mm apart. The digital outputs are 90º out of  phase so that the outputs are in quadrature with the proper ring magnet design.  This allows for easy processing of speed and direction signals. Extremely low- drift amplifi  ers guarantee symmetry between the switches to maintain signal  quadrature. The patented chopper stabilization technique cancels offsets in  each channel, and provides stable operation over the operating temperature and  voltage ranges. An on-chip regulator allows the use of this device over a wide  operating voltage range. Post-assembly factory programming provides sensitive  switchpoints that are symmetrical between the two switches.