MAX6684 19-2306 Rev 0 1/02 Fan-Failure Detector with Integrated Power Switch General Description Features The MAX6684 is an integrated fan-failure detector that Dedicated Fan-Failure Detector detects when a fan exhibits excessive underspeed or a Works with Ordinary 2-Wire Fans locked rotor. This device is especially well suited for criti- cal systems where no fan control, or simple on/off control No Fan Tachometer Output Required is desired. The MAX6684 detects fan failure by evaluat- No Software Development Required ing fluctuations in current at the low side of the fan no tachometer signal is necessary. The output of the device, No Analog Circuit Design Required FAIL, is an active-low, open-drain alarm. The MAX6684 Logic-Level Fan Driver Control can also be used to switch the fan on or off, based on the state of a logic-level input, OFF. This device can be Works with Fans Rated Up to 24V/250mA used with fans rated at up to 24V and 250mA. The MAX6684 is available in an 8-pin SO package, and is specified for operation from -40C to +85C. Applications Desktop PCs Ordering Information Notebooks PART TEMP RANGE PIN-PACKAGE Networking Equipment MAX6684ESA -40C to +85C 8 SO Telecommunications Industrial Applications Typical Operating Circuit Pin Configuration 3.3V TOP VIEW 12V V CC 10k SENSE 1 8 PGND OFF FAIL 2 7 OFF MAX6684 MAX6684 FC+ FAIL GND 3 6 V CC 1 F 0.1 F FC- 4 5 FC+ FC- SENSE GND PGND 0.1 F SO Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com.Fan-Failure Detector with Integrated Power Switch ABSOLUTE MAXIMUM RATINGS Voltages Referenced to GND, Unless Otherwise Noted Continuous Power Dissipation (T = +70C) A V ........................................................................-0.3V to +6.0V 8-Pin SO (derate 5.9mW/C above +70C)..................470mW CC FC+, FC-.....................................................-0.3V to (V + 0.3V) Operating Temperature Range ...........................-40C to +85C CC OFF, FAIL ..............................................................-0.3V to +6.0V Storage Temperature Range .............................-65C to +150C PGND ....................................................................-0.3V to +0.3V Junction Temperature......................................................+150C SENSE to PGND..................................................-0.3V to +28.0V Soldering Temperature (vapor phase, 60s).....................+215C SENSE Current................................................................1400mA Soldering Temperature (infrared, 15s).............................+220C Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS (V = 3.0 to 5.5V, OFF = V , T = -40C to +85C, unless otherwise noted. Typical values are at V = 3.3V, T = +25C.) (Note 1) CC CC A CC A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Supply Voltage V 3.0 5.5 V CC Supply Current I I = 300mA 3.4 mA CC FAN V Shutdown Supply Current I OFF = GND 10 A CC SHDN SENSE-to-PGND Output I = 300mA 0.3 0.66 V FAN Low Voltage SENSE-to-PGND Output R 1 2.2 DSON On-Resistance SENSE Leakage Current V = 26V 1 10 A SENSE V Output Low Voltage I = 3mA 0.8 V FAIL FAIL V Output Leakage Current V = 5.5V 0.1 1 A FAIL FAIL Average SENSE (Fan) Current 50 300 mA SENSE Current Shutdown V = 3V 600 1200 mA CC Thermal Shutdown of SENSE 15C hysteresis 160 C Fan-Current Fluctuation No fault detected 25 400 Hz Frequency V Output Delay After Fault t 0.3 1 2.0 s FAIL FD Minimum Fan-Current Fluctuation No fault detected 15 35 60 mA P-P Level (Note 2) 0.7 x OFF Input High Voltage V V IH V CC 0.3 x OFF Input Low Voltage V V IL V CC OFF Input Current -10 0 1 A Note 1: Specifications to -40C are guaranteed by design and not production tested. Note 2: The MAX6684 is guaranteed to register a fault when the fan current fluctuates less than the minimum it is guaranteed not to register a fault when the fan current is above the maximum. 2 MAX6684