Ampson Technology, Inc. A277

1/6 12/26/2001 REV.1.0
COMPLEMENTARY OUTPUT HALL EFFECT
LATCHED SINK DRIVER

FEATURES

! On-chip Hall sensor with two different sensitivity and hysteresis settings for A277.
! Internal bandgap regulator allows temperature compensated operations and a wide
operating voltage range.
! High output sinking capability up to 400mA for driving large load.
! Lower current change rate reduces the peak output voltages during switching.
! Build in protection diode for chip reverse power connecting.
! Available in die form or rugged low profile 4 pin SIP packages.


GENERAL DESCRIPTION

A277 are integrated Hall sensors with output drivers designed for electronic commutation
of brushless DC motor applications. The device 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 is held until a magnetic flux density reversal falls below
Brp causing DO to be turned off and DOB turned on.

A277 are rated for operation over temperature range from -20
o
C to 85
o
C and voltage
range from 3.5V to 20V. The devices are available in low cost die forms or rugged 4 pin
SIP packages.