Datasheet

 2001-2012 Microchip Technology Inc. DS21450D-page 9
TC650/TC651
5.0 TYPICAL APPLICATIONS
5.1 Reducing Switching Noise
For fans consuming more than 300 mA, a slowdown
capacitor (C
SLOW
) is recommended for reducing
switching PWM induced noise (see Figure 5-1). The
value of this capacitor should be 4.7 µF to 47 µF,
depending on the fan current consumption.
See Application Note 771, “Suppressing Acoustic
Noise in PWM Fan Speed Control Systems”
(DS00771), for more information.
FIGURE 5-1: Reducing Switching Noise.
1
8
27
3
6
4
5
NC
V
DD
C
SLOW
PWM
GND
T
OVER
NC
GND
GND
+5V V
DD
+12V
TC650
TC651
SHDN
GND
PIC
®
DC Fan
500 mA
SHDN
Control
Overtemperature
Alert
Microcontroller