FD1257H

Rev1.7 Nov. 21, 2008

P.2

FEELING

TECHNOLOGY

Pin Connection

Marking Distinguish

Figure.2

Figure.3

Pin Descriptions

Legend: I=input, O=output, I/O=input/output, P=power supply, G=ground

Functional Descriptions

Refer to the block diagram (Figure.1), FD1257H is composed of the following building blocks:

Bias generator

The bias generator provides precise, temperature- and process-insensitive bias references for the analog blocks.

These references guarantee proper operation of the IC under all conditions specified in this specification.

Oscillator

The built-in oscillator provides the clock signal for the digital control logics

Power-on Reset

Used to detect the power-up ramp and reset the digital circuits to achieve correct operation as soon as the power is

ready.

Chopper Amplifier

To achieve a higher magnetic sensitivity the chopper amplifier structure is adopted in this design. Use of this

structure dynamically removes both the offset and flicker noise at the same time.

Digital control logics

Hall sensor part – generates controlling signals for the Hall sensor.

Coil driver part – generates controlling signals for the Coil driver.

Name

I/O

FD1257H

Description

VDD

P

1

Positive power supply

NO

O

2

Driver output

SO

O

3

Driver output

VSS

G

4

Ground

1257H

1

2

3

4

YMV-XX

Lot Number

1257H

YMV-XX

Mass Production Version

Half month (ex:A,B ~ X)

Year (ex:2008

8)