FD2157H

Rev1.2 Jul. 06, 2009

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), FD2157H 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 logic.

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 Logic

Hall sensor part – generates magnetic pole signals from the Hall-effect sensor.

Driver part – generates switching signals to the open drain MOS driver.

Timer part – generates an interval of time when rotor locked event is occurred.

Name

I/O

FD2157H

Description

VDD

P

1

Positive Power Supply

NO

O

2

Driver Output 1

SO

O

3

Driver Output 2

VSS

G

4

Ground

2157H

1

2

3 4

YMV-XX

Lot Number

2157H

YMV-XX

Mass Production Version

Half month(ex:A,B ~ X)

Year (ex:2008 8)