US90A / US91A

24V Hall IC Fan Driver

390109026302

Page 7 of 12

Data Sheet

Rev 002

Apr/07

0

0.1

0.2

0.3

0.4

0.5

-40

-20

0

20

40

60

80

100

120

Tj (°C)

VDD=5V ; Iol=10mA

VDD=24V ; Iol=10mA

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

-40

-20

0

20

40

60

80

100

120

140

Ta (°C)

12 Application Information

12.1 Typical application with pull-up

resistor

12.2 Configuration for reverse voltage /

ground hot-switch protection and

enhanced ESD module protection

13 Application Comments

Figure 12.2 shows the application including several external protections.

the positive supply point is still connected. This capacitor provides a path to ground for the remaining energy

in the coil which has to be evacuated. Without it, the energy can flow from OUT1/OUT2 to the FG/RD driver,

without any limitation and may cause EOS damage.

Its value has to be tuned depending on the coils characteristics. Bigger inductance requires bigger capacitor.

and filter fast current stress on OUT1 and OUT2, resulting in better ESD protection. Adding the optional

ESD stress at relatively high value without damage.