3235

3235 DUAL-OUTPUT HALL-EFFECT SWITCH 3235 DUAL-OUTPUT HALL-EFFECT SWITCH Type UGN3235K Hall-effect sensors are bipolar integrated circuits designed for commutation of brushless dc motors, and other rotary encoding applications using multi-pole ring magnets. The device features two outputs which are independently activated by magnetic fields of opposite polarity. Each sensor IC includes a Hall voltage generator, two Schmitt triggers, a voltage regulator, output transistors, and on-board reverse polarity protection. The regulator enables these devices to operate from voltages ranging between 4.5 V and 24 V. On-chip compensation circuitry stabilizes the switch points over temperature. Each open-collector output is independently operated by the proper amount and polarity of incident magnetic flux. Output 1 responds only to the positive flux from the south pole of a magnet, Output 2 to the negative flux from the north pole of a magnet. When the sensor experiences the field of a south magnetic pole greater than the maximum operate point of Output 1, that output switches to the LOW state and Output 2 is unaffected. When the incident flux falls below the minimum release point for Output 1, that output returns to the HIGH state and Output 2 remains unchanged. Output 2 independently responds in the same manner to the negative flux from the north magnetic pole of a magnet. Figure 1 shows a zone in the region of 0 G, tH, where both outputs are in the HIGH or OFF state. This constitutes a...