A277

A277 is integrated Hall sensors with output drivers designed for electronic commutation  of brushless DC motor applications. The A277 includes an on-chip Hall voltage generator  for magnetic sensing, a comparator that amplifies the Hall voltage, and a Schmitt trigger to  provide switching hysteresis for noise rejection, and complementary open-collector drivers  for sinking large current loads. An internal bandgap regulator is used to provide  temperature compensated supply voltage for internal circuits and allows a wide operating  supply range.
 
If a magnetic flux density larger than threshold Bop, DO is turned on(low) and DOB is  turned off (high). The output state of A277 is held until a magnetic flux density reversal falls below  Brp causing DO to be turned off and DOB turned on.