Data Sheet
COMPLEMENTARY OUTPUT HALL EFFECT LATCH
General Description
The AH277A is an integrated Hall sensor with output
driver designed for electronic commutation of brush-
less DC motor applications. The device includes an on-
chip Hall sensor for magnetic sensing, an amplifier
that amplifies the Hall voltage, a Schmitt trigger to
provide switching hysteresis for noise rejection, a tem-
perature compensation circuit to compensate the tem-
perature drift of Hall sensitivity and two
complementary open-collector drivers for sinking
large load current. It also includes an internal band-gap
regulator which is used to provide bias voltage for
internal circuits.
Placing the device in a variable magnetic field, if the
magnetic flux density is larger than threshold B
OP
, the
pin DO will be turned low (on) and pin DOB will be
turned high (off). This output state is held until the
magnetic flux density reverses and falls below B
RP,
then causes DO to be turned high (off) and DOB
turned low (on).
AH277A is available in TO-94 (SIP-4L) package.
AH277A
Features
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On-Chip Hall Sensor
3.5V to 16V Supply Voltage
400mA (avg) Output Sink Current
Reversed Supply Voltage Protection
-20
o
C to 85
o
C Operating Temperature
Low Profile TO-94 (SIP-4L) Package
ESD Rating: 300V (Machine Model)
Applications
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Dual-Coil Brushless DC Motor
Dual-Coil Brushless DC Fan
Revolution Counting
Speed Measurement
TO-94
Figure 1. Package Type of AH277A
Jul. 2006 Rev. 1. 2
1
BCD Semiconductor Manufacturing Limited
BCDSEMI [ BCD SEMICONDUCTOR MANUFACTURING LIMITED ]
