MAX1669:Fan Controller and Remote Temperature Sensor with SMBus Serial Interface

Industry First - Temperature Sensor with PWM and Linear Fan Control

The MAX1669 fan controller includes a precise digital thermometer that reports the temperature of a remote sensor. The remote sensor is a diode-connected transistor-typically a low-cost, easily mounted 2N3906 PNP type-replacing conventional thermistors or thermocouples. Remote accuracy is ±3°C for transistors from multiple manufacturers, with no calibration needed. The MAX1669 has an independent fan controller with a low-current logic output requiring external power components to interface to a DC brushless fan. The fan controller has two modes of operation: a low-frequency (20Hz to 160Hz) PWM mode intended for driving the fan motor, or a high-impedance DAC output that generates a variable DC control voltage. In PWM mode, the FAN frequency can be synchronized to an external clock. Other key features include general-purpose inputs/outputs (GPIOs) for fan presence detection and a thermostat output intended as a fan override signal in case the host system loses the ability to communicate. The internal ADC has a wide input voltage range and gives overrange readings when too large an input voltage is applied. Other error-checking includes temperature out-of-range indication and diode open/short faults. The MAX1669 is available in a space-saving 16-pin QSOP package that allows it to fit adjacent to the SLOT1 connector.

Key Features
  • Measures Remote CPU Temperature
  • No Calibration Required
  • 20Hz to 160Hz PWM Output for Fan
  • PWM Frequency Sync Input (260kHz)
  • Flexible Fan Interface: Linear or PWM
  • SMBus 2-Wire Serial Interface
  • Programmable Under/Overtemperature Alarms
  • ALERT-bar Latched Interrupt Output
  • OVERT-bar Thermostat Output
  • Two GPIO Pins
  • Write-Once Configuration Protection
  • Supports SMBus Alert Response
  • ±3°C Temperature Accuracy (-40°C to +125°C, remote)
  • 3µA Standby Supply Current
  • +3V to +5.5V Supply Range
  • Small 16-Pin QSOP Package
  • Remote diode sensor, PWM and linear fan control, dual alarms
MAX1669: Typical Operating Circuit
MAX1669: Typical Operating Circuit
Applications/Uses
  • Computers: Desktop, Workstation, Server
  • Notebook Computers
  • Pentium® CPU Cooling
  • Servers
  • Workstations
DataSheet
titleDownload file
MAX1669 Data SheetMAX1669.pdf
Parametrics
Part NumberSensor TypeFan Cntrl.InterfaceAccuracy
(±°C)
Temp. Thresh.
(°C)
Temp. Resolution
(bits)
Package/Pins
MAX1669RemotePWM2-Wire/I2C/SMBus3Programmable8QSOP/16
Design kits & evaluation modules
Quality and Environmental Data
Related Products
  • MAX1619:Remote/Local Temperature Sensor with Dual Alarm Outputs and SMBus Serial Interface
  • MAX1617A:Remote/Local Temperature Sensor with SMBus Serial Interface
Ordering Information
Part NumberStatusRecommended ReplacementPackageTempRoHS
MAX1669EEENo Longer AvailableMAX1669EEE+QSOP,;16 pin;30.9 mm²-55°C to +125°CNo
MAX1669EEE+ActiveQSOP,;16 pin;30.9 mm²-40°C to +85°CLead Free
MAX1669EEE+TActiveQSOP,;16 pin;30.9 mm²-55°C to +125°CLead Free
MAX1669EEE-TNo Longer AvailableMAX1669EEE+TQSOP;16 pin-55°C to +125°CSee data sheet
MAX1669EVKITActiveEVKIT;-40°C to +85°CSee data sheet
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