Document
19-2306; Rev 0; 1/02
Fan-Failure Detector with Integrated Power Switch
General Description
The MAX6684 is an integrated fan-failure detector that detects when a fan exhibits excessive underspeed or a locked rotor. This device is especially well suited for critical systems where no fan control, or simple on/off control is desired. The MAX6684 detects fan failure by evaluating fluctuations in current at the low side of the fan; no tachometer signal is necessary. The output of the device, FAIL, is an active-low, open-drain alarm. The MAX6684 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 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 -40°C to +85°C. o Dedicated Fan-Failure Detector o Works with Ordinary 2-Wire Fans o No Fan Tachometer Output Required o No Software Development Required o No Analog Circuit Design Required o Logic-Level Fan Driver Control o Works with Fans Rated Up to 24V/250mA
Features
MAX6684
Applications
Desktop PCs Notebooks Networking Equipment Telecommunications Industrial Applications
PART MAX6684ESA
Ordering Information
TEMP RANGE -40°C to +85°C PIN-PACKAGE 8 SO
Typical Operating Circuit
3.3V
Pin Configuration
TOP VIEW
12V VCC OFF 10kΩ
SENSE 1 FAIL 2
8 7
PGND OFF VCC FC+
MAX6684
FC+ 1µF 0.1µF FCGND SENSE PGND 0.1µF FAIL
MAX6684
GND 3 6 5 FC- 4
SO
________________________________________________________________ Maxim Integrated Products
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For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
Fan-Failure Detector with Integrated Power Switch MAX6684
ABSOLUTE MAXIMUM RATINGS
Voltages Referenced to GND, Unless Otherwise Noted VCC ........................................................................-0.3V to +6.0V FC+, FC-.....................................................-0.3V to (VCC + 0.3V) OFF, FAIL ..............................................................-0.3V to +6.0V PGND ....................................................................-0.3V to +0.3V SENSE to PGND ..................................................-0.3V to +28.0V SENSE Current................................................................1400mA Continuous Power Dissipation (TA = +70°C) 8-Pin SO (derate 5.9mW/°C above +70°C)..................470mW Operating Temperature Range ...........................-40°C to +85°C Storage Temperature Range .............................-65°C to +150°C Junction Temperature ......................................................+150°C Soldering Temperature (vapor phase, 60s).....................+215°C Soldering Temperature (infrared, 15s).............................+220°C
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 an.