ATS278
Two Phase Hall Effect Latch With FG Output


This datasheet contains new product information. Anachip Corp. reserves the rights to modify the product specification without notice. No liability is assumed as a result of the use of
this product. No rights under any patent accompany the sale of the product.
Rev. 1.0 Oct 4, 2005
1/6

„ Features

- On-chip Hall plate
- Operating voltage: 3.5V~20V
- Internal bandgap regulator allows temperature
compensated operations and a wide operating
voltage range
- High output sinking capability up to 400mA for
driving large load
- Built-in protection diode only for chip reverse
power connecting
- Frequency Generation (FG) output
- Package: SIP-5L

„ Applications

- Dual-coil Brush-less DC Motor
- Dual-coil Brush-less DC Fan
- Revolution Counting
- Speed Measurement


„ General Description

ATS278 is an integrated Hall sensor with two output
drivers and rotor speed output, typically designed
for electronic commutation of two-phase brush-less
DC fan applications.
On-chip Hall sensor will generate Hall voltage due
to magnetics sensing. The amplifier will amplify the
Hall voltage. The Schmitt trigger determines
switching hysteresis and then control internal
driver’s on/off to sink load current. Meanwhile, An
internal bandgap regulator is used to provide stable
bais due to temperature-compensation. FG pin will
provide switching frequency of driver. Major feature
is to minimize the external components by
building-in FG output transistor.
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.
„ Ordering Information
ATS278 X - X X - X
P: SIP-5L
Package Lead
L : Lead Free
Wafer Body
Magnetic
Characteristics
Blank or
A~Z : if necessary
to specify
A or B

*Packing: Bulk

„ Typical Application Circuit
278
1
54
32
5V/12V
Coil1 Coil2
Rpu
C1
+
Speed
R1
R2
C1 C2
R1 = R2 = 47Ω
μC1 = C2 = 2.2 F
The R, C value need to be fine tuned
base on coils design.

5V/12V DC Brush-less Fan with FG output function