Data Sheet
SINGLE PHASE HALL EFFECT LATCH
General Description
The AH477A is an integrated Hall sensor with H-
bridged output driver designed for brushless DC motor
applications. The device includes an on-chip Hall sen-
sor for magnetic sensing, an amplifier that amplifies
the Hall voltage, a comparator to provide switching
hysteresis for noise rejection, a bi-directional drivers
for sinking and driving large current load. It also
includes an internal bandgap regulator to provide tem-
perature compensated bias for internal circuits and
allows a wide operating supply voltage range.
Placing the device in a variable magnetic field, if the
magnetic flux density is larger than threshold B
OP
, the
DO is turned to sink and DOB is turned to drive. This
output state is held until the magnetic flux density
reverses and falls below B
RP,
then causes DO to be
turned to drive and DOB turned to sink.
The AH477A is available in TO-94 (SIP-4L) package.
AH477A
Features
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On-Chip Hall Sensor
Operating Voltage: 3.5V to 18V
H-Bridge Output Drivers for Single Coil
Internal Bandgap Regulator for Temperature
Compensation
Low Output Switching Current Noise
Operating Temperature: -20
o
C to 85
o
C
Low Profile TO-94 (SIP-4L) Package
ESD Rating: 6000V (Human Body Model)
Suitable for PWM Power Supply Control Speed
Applications
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Single-coil Brushless DC Motor
Single-coil Brushless DC Fan
TO-94
Figure 1. Package Type of AH477A
Oct. 2009 Rev. 1. 2
1
BCD Semiconductor Manufacturing Limited
BCDSEMI [ BCD SEMICONDUCTOR MANUFACTURING LIMITED ]
