MIC502YM Microchip

MIC502 Fan Management IC General Description Features The MIC502 is a thermal and fan management IC that Temperature-proportional fan speed control supports the features for NLX/ATX power supplies and Low-cost, efficient PWM fan drive other control applications. 4.5V to 13.2V IC supply range Fan speed is determined by an external temperature Controls any voltage fan sensor, typically a thermistor-resistor divider, and Overtemperature detection with fault output (optionally) a second signal, such as the NLX FanC Integrated fan startup timer signal. The MIC502 produces a low-frequency pulse-width Automatic user-specified sleep mode modulated output for driving an external motor drive transistor. Low-frequency PWM speed control allows Supports low-cost NTC/PTC thermistors operation of standard brushless DC fans at low duty-cycle 8-pin DIP and SOIC packages for reduced acoustic noise and permits the use of a very small power transistor. The PWM time base is determined Applications by an external capacitor. NLX and ATX power supplies An open-collector overtemperature fault output is asserted Personal computers if the primary control input is driven above the normal File servers control range. Telecom and networking hardware The MIC502 features a low-power sleep mode with a user- Printers, copiers, and office equipment determined threshold. Sleep mode completely turns off the Instrumentation fan and occurs when the system is asleep or off (both control inputs very low). A complete shutdown or reset can Uninterruptible power supplies also be initiated by external circuitry as desired. Power amplifiers The MIC502 is available as 8-pin plastic DIP and SOIC packages in the 40C to +85C industrial temperature range. Datasheets and support documentation are available on Micrels web site at: www.micrel.com. Typical Application Micrel Inc. 2180 Fortune Drive San Jose, CA 95131 USA tel +1 (408) 944-0800 fax + 1 (408) 474-1000 Micrel, Inc. MIC502 Ordering Information Part Number Temperature Range Package Lead Finish MIC502YN 40 to +85C 8-Pin Plastic DIP Pb-Free MIC502YM 40 to +85C 8-Pin SOIC Pb-Free Pin Configuration 8-Pin SOIC (M) 8-Pin DIP (N) (Top View) Pin Description Pin Number Pin Name Pin Function Thermistor 1 (input): Analog input of approximately 30% to 70% of V produces active duty cycle DD 1 VT1 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 2 CF generator timing capacitor. The recommended CF is 0.1F for 30Hz PWM operation. Sleep threshold (input): The voltage on this pin is compared to VT1 and VT2. When V < V T1 SLP 3 VSLP and V < V the MIC502 enters sleep mode until V or V rises above V . (V = V + T2 SLP T1 T2 WAKE WAKE SLP V ). Grounding V disables the sleep-mode function. HYST SLP 4 GND Ground Thermistor 2 (input): Analog input of approximately 30% to 70% of V produces active duty cycle DD 5 VT2 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 6 /OTF fault condition (V > V ) when active. T1 OT Driver output: Asymmetrical-drive active-high complimentary PWM output. Typically connect to 7 OUT base of external NPN motor control transistor. 8 VDD Power supply (input): IC supply input may be independent of fan power supply. Revision 3.0 October 6, 2014 2