US65 / US66

Two-Coil Low Noise Fan Driver

High Output Current

3901090209

Page 3 of 12

Preliminary Datasheet

Rev 006

Jan/07

3 Glossary of Terms

Two-coil fan

A fan with two-coil windings where current alternates from 1 coil to the other

depending on the direction of the magnetic field.

MilliTesla (mT), Gauss

Units of magnetic flux density :

1mT = 10 Gauss

Peak output current

The current flowing in the coil at start-up, only limited by the coil resistance

Continuous output current

Average absolute value of the output current when the fan is spinning.

Locked rotor

The state when the fan stopped spinning due to mechanical blockage.

FG

Frequency generator or tachometer output

RD

Rotation detection or alarm output

4 Absolute maximum ratings

Parameter

Symbol

Value

Units

Supply Voltage

-12 to 18

V

FG / RD voltage

-7 to 18

V

Voltage on pin SLOPE

-0.5 to 18

V

Peak output current

1200

mA

Continuous output current

600

mA

Operating Temperature Range

-40 to 85

°C

Junction temperature

125

°C

Storage Temperature Range

-55 to 150

°C

Magnetic flux density

B

Unlimited

mT

Table 1: Absolute maximum ratings

Exceeding the absolute maximum ratings may cause permanent damage. Exposure to absolute-maximum-

rated conditions for extended periods may affect device reliability.

5 Pin definitions and descriptions

Pin Name

Function

Pin number (DC)

FG (RD)

Tachometer (Alarm) open-drain output

1

VDD

Power Supply pin

2

SLOPE

Slope Control pin

3

OUT1

Open Drain Coil Driver 1

4

GND

Ground pin

5

OUT2

Open Drain Coil Driver 2

6

NC

Not connected

7

NC

Not connected

8

Table 2: Pin definitions and descriptions