MLX902xx Name of Sensor

Rev Y.X

22/Aug/98

Page 1

US79 Series

CMOS Power Hall IC

US79 CMOS Power Hall IC

Rev 3.0

23/Jan/01

Page 1

Features and Benefits

ESD Tolerance IC>7,000V

ESD Tolerance of Fan >15,000V

Built-in Reverse Voltage Protection

Built-in RFI Filter

Power Efficient CMOS and Power MOSFET Drivers allow 400mA without overheating

Built-in Zener Diodes Protect Outputs

Eliminates all Fan Components

Eliminate PC Board

5V and 12V Operation

High Sensitivity for switching symmetry

Locked Rotor Shutdown

Applications

Fan Sizes up to 90mm

Current Range up to 400mA

Ordering Information

Part No.

Temperature Suffix

Package

Temperature Range

US79

K

UA

-40

US79

K

8-Pin Narrow SOIC

-40

Description

The US79KUA is the most advanced Smart Fan

Control Hall IC. It is designed for 5V and 12V cooling

commutation. The chip contains many features to

allow survival in a harsh environment. The IC was

designed to eliminate all discrete components such

as capacitors, resistors, transistors, diodes, PC

board and associated labor, replacing US$0.25 to

US$0.35 in direct cost.

The K rating guarantees proper operation up to an

ambient temperature of 125°C. Hall IC circuitry and

power FET output provide a low power dissipation

cool chip.

Locked Rotor conditions are detected by the IC when

there is no motion for one second and will shut off

the motor drive for five seconds. Then, the IC will

turn on the drive current for one second. This

sequence continues indefinitely until the locked rotor

condition is fixed. This feature prevents overheating.

Maximum ambient temperature is determined by

driver power dissipation. For instance, at 125C

ambient, driver power cannot exceed 125mW or

250mA. Future versions will offer optional features.

Functional Diagram

Voltage

Regulator

1

2

3

Hall Latch

Output 1

Output 2

Control and

Protection

GND

-

+