TC650_04 Datasheet, PDF (9/16 Pages) STMicroelectronics – Tiny Integrated Temperature Sensor & Brushless DC Fan Controller with Overtemperature Alert

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.
TC650/TC651
PICmicro^®
Microcontroller
SHDN
Control
Overtemperature
Alert
+12V
+5V V_DD
TC650
TC651
DC Fan
500 mA
1 ^VDD
PWM 8
2 NC
GND 7
3 SHDN ^TOVER 6
4 GND
NC 5
GND
C_SLOW
GND
FIGURE 5-1:
Reducing Switching Noise.
 2004 Microchip Technology Inc.
DS21450C-page 9