Datasheet Linear Technology LTC1840IGN#TRPBF

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Design Notes

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  LTC1840: I2C Fan Control Ensures Continuous System Cooling &mdash DN270
  PDF, 82 Kb, File published: Oct 2, 2001
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  I2C Fan Control Ensures Continuous System Cooling
  Design Note 270
  Dilian Reyes
  slowing down due to worn bearings or halted from a
  jam will cause an overflow in the internal counter and
  a corresponding bit is set low in the fault register. The
  system controller can then take action, shutting down
  the faulty fan and summoning maintenance. Introduction
  Linear Technology’s LTC ®1840 is a dual fan speed
  controller for high availability servers and other rackbased network and telecom equipment. The LTC1840
  offers advanced control and monitoring capabilities,
  accessed via an I2C and SMBus compatible 2-wire
  serial interface. In addition to two fan speed control
  channels, the LTC1840 also includes a fan tachometer and fault monitoring, nine slave addresses
  and four general-purpose programmable I/O pins
  in a 16-pin SSOP package. Adjusting fan speed to
  match instantaneous cooling requirements increases
  energy efficiency and reduces noise. By operating at
  reduced speeds, fan bearings are subjected to less
  wear, increasing fan life and reliability. The chip contains four general purpose input/output
  (GPIO) pins that are configured independently. As opendrain outputs, they can be set high, low or to pulse at a
  1.5Hz rate. The outputs are rated at 10mA sink current
  for compatibility with LEDs. Conп¬Ѓgured as inputs, the …

Articles

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  I2C Dual Fan Speed Controller Increases Efficiency and Reduces Noise &mdash LT Journal
  PDF, 46 Kb, File published: Dec 1, 2001
  Extract from the document

  DESIGN IDEAS I2C Dual Fan Speed Controller
  Increases Efficiency and
  by Dilian Reyes
  Reduces Noise
  Busy servers and rack-based network and telecom equipment rely on
  hard-working cooling systems to keep
  from melting down. The simplest cooling system is a bank of fans running
  at full tilt, all of the time. This approach ensures a cool environment,
  but overcompensation is neither efficient, nor is it good for the fans. High
  output fans that work full time do not
  last very long (their bearings wear
  out), are not very efficient (they use
  power also), and are noisy (especially
  when their bearings wear out). The
  LTC1840 dual fan speed controller
  reduces the wear on bearings, and
  noise, by continuously adjusting fan
  speed to match the instantaneous
  cooling requirements of the system. REGULATOR
  12V VIN FAN POWER (1.36V TO 12VMAX) VO
  VFB
  1.23V FB R1
  105k …

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Manufacturer's Classification

• Data Conversion > Digital-to-Analog Converters (DAC) > Special Function DACs | Unipolar Digital-to-Analog Converters (DAC)
• Power Management > Power Control > Fan Speed Controllers

Other Names:

LTC1840IGNTRPBF, LTC1840IGN TRPBF