© 2002 Microchip Technology Inc.

DS21453B-page 7

TC652/TC653

TABLE 3-3:

TEMPERATURE SELECTION

GUIDE

Note: The Bold Type temperature settings are available for ordering.

Contact factory for other temperature selections.

anywhere from 25°C to 35°C.

As an example, suppose you wanted the fan to run at

40% speed at 25°C or less and go to full speed at

45°C. You would order the part number TC652AEVUA.

As another example, suppose you wanted the fan to

turn on at 30°C and go to full speed at 45°C. You

would order the part number TC653BEVUA.

4.0

TYPICAL APPLICATIONS

4.1

Reducing Switching Noise

For fans consuming more than 300mA, a slowdown

switching PWM induced noise (see Figure 4-1). The

value of this capacitor should be 4.7

µFto47µF,

depending on the fan current consumption.

See Application Note AN771 “Suppressing Acoustic

Noise in PWM Fan Speed Control Systems” for more

information.

FIGURE 4-1:

REDUCING SWITCHING

NOISE

Temp.

Range °C

Part #

10°C

25

35

AC

30

40

BD

35

45

CE

15°C

25

40

AD

30

45

BE

20°C

25

45

AE

30

50

BF

35

55

CG

30°C

25

55

AG

1

8

2

7

3

6

4

5

PWM

GND

NC

GND

GND

0.01µF

10µF

2

Ω

1k

Ω

+12V

TC652

TC653

SHDN

FAULT

GND

µController

DC Fan

400mA

Max.

SHDN Control

Fan Fault Alert

Over-Temp

Alert

-