US72/73

Single Coil Fan Driver

3901090261

Page 3 of 9

Data Sheet

Rev. 002

May/04

1. Glossary of Terms

Full Bridge: Two output drivers that can both source or sink current. When a load is placed between the

drivers, current can flow through the load in both directions.

FG: The Frequency Generator or tachometer signal; provides one pulse for every magnetic pole

RD: The Rotation detection or Lock Alarm signal is high when the rotor is blocked or spinning very slowly.

MilliTesla (mT), Gauss: Units of magnetic flux density; 1 milliTesla = 10 Gauss

Single Coil Fan: a fan with only one coil winding, usually requiring a bipolar or full-bridge driver

Locked rotor: The condition of a fan that has stopped spinning due to mechanical blockage

2. Absolute Maximum Ratings

28V

Output Voltage, FG or RD

28V

500mA

-40 to 85

°C

125

°C

-55 to 150

°C

ESD Sensitivity (AEC Q100 002)

2KV

Magnetic Flux Density

No limit

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

maximum-rated conditions for extended periods may affect device reliability.

3. US72/73 Electrical Specifications

Parameter

Symbol

Test Conditions

Min

Typ

Max

Units

Supply Voltage

Operating

4.5

28

Volts

Supply Current

4

6

mA

On Resistance

3

5.3

Ohms

Bridge Current

Peak

500

mA

Bridge Current

Continuous

350

mA

Thermal Resistance

one-sided PCB, zero LFPM

150

o

C/Watt

Locked-Rotor Period

0.25

S

Locked-Rotor period

1.25

S

Freewheel Switching delay

200

uS

FG/RD Output Leakage

10

uA

FG/RD On voltage

Iout = 5mA

0.5

Volts