MIC502

Micrel

MIC502

164

May 1999

Pin Description

Pin Number

Pin Name

Pin Function

1

VT1

Thermistor 1 (Input): Analog input of approximately 30% to 70% of V

DD

produces active duty cycle of 0% to 100% at driver output (OUT). Connect to

external thermistor network (or other temperature sensor). Pull low for

shutdown.

2

CF

PWM Timing Capacitor (External Component): Positive terminal for the

PWM triangle-wave generator timing capacitor. The recommended C

0.1

µF for 30Hz PWM operation.

3

VSLP

Sleep Threshold (Input): The voltage on this pin is compared to V

When V

V

disables the sleep-mode function.

4

GND

Ground

5

VT2

Thermistor 2 (Input): Analog input of approximately 30% to 70% of V

DD

produces active duty cycle of 0% to 100% at driver output (OUT). Connect to

motherboard fan control signal or second temperature sensor.

6

/OTF

Overtemperature Fault (Output): Open-collector output (active low).

Indicates overtemperature fault condition (V

7

OUT

Driver Output: Asymmetical-drive active-high complimentary PWM output.

Typically connect to base of external NPN motor control transistor.

8

VDD

Power Supply (Input): IC supply input; may be independent of fan power

supply.

Pin Configuration

1

2

3

4

8

7

6

5

VDD

OUT

OTF

VT2

VT1

CF

VSLP

GND

8-Pin SOIC (M)

8-Pin DIP (N)