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

5

4

3

2

5V/12V

Coil1

Coil2

C1

+

Speed

R1

R2

C1

C2

R1 = R2 = 47Ω

μ

C1 = 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