MIC502 Datasheet, PDF (2/11 Pages) Micrel Semiconductor – Fan Management IC Advance Information

MIC502
Pin Configuration
VT1 1
CF 2
VSLP 3
GND 4
8 VDD
7 OUT
6 OTF
5 VT2
8-Pin SOIC (M)
8-Pin DIP (N)
Micrel
Pin Description
Pin Number
1
2
3
4
5
6
7
8
Pin Name
VT1
CF
VSLP
GND
VT2
/OTF
OUT
VDD
Pin Function
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.
PWM Timing Capacitor (External Component): Positive terminal for the
PWM triangle-wave generator timing capacitor. The recommended C_F is
0.1µF for 30Hz PWM operation.
Sleep Threshold (Input): The voltage on this pin is compared to V_T1 and V_T2.
When V_T1 < V_SLP and V_T2 < V_SLP the MIC502 enters sleep mode until V_T1 or
V_T2 rises above V_WAKE. (V_WAKE = V_SLP + V_HYST.) Grounding VSLP
disables the sleep-mode function.
Ground
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.
Overtemperature Fault (Output): Open-collector output (active low).
Indicates overtemperature fault condition (V_T1 > V_OT) when active.
Driver Output: Asymmetical-drive active-high complimentary PWM output.
Typically connect to base of external NPN motor control transistor.
Power Supply (Input): IC supply input; may be independent of fan power
supply.
MIC502
164
May 1999